The literature review usually precedes a research proposal and results section. Its goals are to situate the current study within the body of literature and to provide context for the particular reader. Literature reviews are important for research in nearly every academic field.
21. 21
National Library of Medicine
The world’s largest biomedical library
NLM is the producer of:
MEDLINE
PubMed
MedlinePlus.gov
Visit the National Library’s Home Page at:
http://www.nlm.nih.gov
22. PUBMED
Provides free access to medical database
Links to full-text articles
Provides Advanced search
Links to related articles and provides
discovery tools for other data that may be
of interest.
23. PubMed’s Sponsor
Introduction to the U.S. National Library of Medicine (NLM)
The National Network of Libraries of Medicine®
NN/LM Web site: http://nnlm.gov
24. What’s in PubMed
Most PubMed records are MEDLINE citations.
Other records include those in different stages of
processing (including records provided directly
from the journal publisher) but destined to be
MEDLINE citations.
A relatively small number of records that are
included in PubMed but not selected for MEDLINE.
25. 25
What is MEDLINE?
The world’s largest biomedical database
MEDLINE covers:
Medicine
Dentistry
Veterinary Science
Nursing
Other Biological Sciences
26. 26
What is MEDLINE?
4,800 journals are indexed
Covers all aspects of biosciences and
healthcare
Database of 14+ million journal citations
27. 27
What is MEDLINE?
Covers 1966 to the present
Coverage worldwide, 85% are in English
76% have abstracts
28. MEDLINE
MEDLINE is NLM's bibliographic
database of citations and abstracts,
currently
> 5,600 biomedical journals
All citations in MEDLINE are
assigned
29. MEDLINE Citations
PubMed provides access to MEDLINE
Scope of MEDLINE includes such diverse topics
as microbiology, delivery of health care, nutrition,
pharmacology and environmental health. The
categories covered in MEDLINE include
everything from anatomy, organisms, diseases,
psychiatry, and psychology to the physical
sciences.
contains over 17 million references dating back to
1948.
New material is added Tuesday through Saturday.
30.
31.
32. MeSH
National Library of Medicine's
controlled vocabulary thesaurus.
consists of sets of terms naming
descriptors in a hierarchical structure
that permits searching at various
levels of specificity.
33. 33
What is MeSH?
MeSH – Medical Subject Headings
Controlled vocabulary terms
○ Brain Edema, Otitis Media, Myocardial Infarction
46. 46
PubMed.gov
Translates lay terms into medical subject
headings
Heart Attack into Myocardial Infarction
Links to selected free articles through
publishers’ web sites
Most articles are written for health
professionals
48. Boolean Strategies
- If you are retrieving too many records on
your topic, try adding another search term
with the connector AND.
49. Boolean Strategies
If you are retrieving too few records on
your topic, try adding another search term
with the connector OR.
50. Boolean Strategies
If you are retrieving too many records on an
unrelated topic, try eliminating a word with the
connector NOT.
51.
52.
53. Truncation & Wildcards
To increase the number of hits retrieved, you might
consider using a truncation symbol. Truncation will
pick up variations of a word stem. Truncation
symbols vary, depending on the database.
e.g., critic* will find critic, critics, criticism, critical,
etc.
The wildcard symbol can be used to replace one
letter in a word. This will instruct the computer to do
a search and match all letters in the word and use
any letter to replace the wildcard symbol.
e.g., Wom?n will retrieve records with woman and
women.
54. Basic Searching
Quotation Marks
“ “
Requires words to searched as a phrase, in the exact order you
type them.
Common Words
Usually Ignored + or “ ”
to search them
Search which versus that.
Only versus is searched on. Which and that are ignored.
To require common words to be searched:
+which versus +that ”which versus that”
Excluding
-word -“phrase in
quotes”
“acute pancreatitis” diet –cat –dog –“pancreatic cancer”
55. Basic Searching
OR allows more than one term
allows pages with at least one of
the terms
OR requires at least one of the terms joined by it to
appear somewhere in the document, in any order.
“abdominal pain” OR blacks ear OR nose OR
throat
The more words you enter connected by OR, the
more documents you get. Broadens the search..
USES:
o The OR operator is generally used to join similar,
equivalent, or
synonymous concepts.
"global warming" OR "greenhouse effect"
Abdomen Pain
56. Basic Searching
AND (default)
is the small overlap where both
terms occur
AND is the default and only needs to be typed if you
are using other Boolean operators with ( ).
Ex.
infopeople training is logically the same as
infopeople and training
The more words you enter connected by AND, the
fewer documents you get. All your words will be
searched on
USES:
o The AND operator is generally used to join
different kinds of
concepts, different aspects of the question.
o "global warming" AND "sea level rise" AND
california
Abdomen Pain
57. Basic Searching
AND NOT
excludes pages that mention
PAIN, even if they also mention
ABDOMINAL
Excludes documents containing whatever follows it.
The AND NOT operator is generally used after you
have performed a search, looked at the results, and
determined that you do not want to see pages
containing some word or phrase.
USES:
• The AND NOT operator should be used with
extreme caution, because it eliminates the entire
page, and some pages may be of value to you
for other information they contain. I almost never
use and not for this reason.
o "global warming" AND "sea level rise" AND
NOT california - The first two terms must be
somewhere and any page containing california will
be thrown out.
Abdomen Pain
58. Basic Searching
NEAR
dogs NEAR cats
requires both terms,
like AND, with the
added requirement
that they be within 16
words of each other
Requires the term following it to occur within a
certain proximity of the preceding word in the
search. In Exalead.com, NEAR requires the terms
to be within 16 words of each other in either
direction.
Joining words by NEAR gives you fewer documents
than AND, because it requires the words to be
closer together.
USES:
o The NEAR operator is used when you want to
require that certain terms appear in the same
sentence or paragraph of the document. o "global
warming" NEAR "sea level rise" - Requires the
two phrases to occur within 16 words of each other,
in either direction.
59. Basic Searching
( )
parentheses:
"Nesting"
Require the terms and operations that occur
inside them to be searched first. This is called
"nesting."
Parentheses MUST BE USED to group terms joined
by OR when there is any other Boolean operator in
the search.
o "global warming" AND "sea level rise" AND
(california OR "pacific coast*") - Requires first
two terms somewhere in all documents, and either
california or pacific coast.
• Parentheses also MUST BE USED with NEAR:
o ("global warming" NEAR "sea level rise") AND
(california OR "pacific coast*") - Requires sea
level rise to be within 16 words of global warming;
the rest can be anywhere in the pages. The
parentheses guarantee that the effect of near stops
with sea level rise.
60.
61. 61
Searching PubMed
Let us use this search:
“I was exposed to asbestos for years in
school. Can that cause gastrointestinal
cancer?”
63. 63
How Does PubMed Interpret What You
Type in the Box?
PubMed uses Automatic Term Mapping
and maps to:
Medical Subject Headings – medical terms
Phrases
Author Name – lastname initial(s), e.g., smith j,
smith ja
Journal Titles – full journal title, MEDLINE
abbreviation, ISSN
How do you think PubMed searched your terms?
65. 65
When to Limit?
There are many reasons for refining a
search strategy. You may want to:
Exclude foreign language titles
Look for articles published within a certain
timeframe
Retrieve articles that focus on women or
perhaps just children
68. 68
Working with Results
Citations display in batches of 20 with
most recent additions on top.
Use the check boxes to select multiple
citations to view
Click on icons for more information,
such as the abstract
69. 69
A Closer Look at Starting a Search
Enter search terms here
and then click on Go.
Add Limits like date, language,
publication type, and more.
72. 72
The Clipboard tab
Lets you keep track of the good ones while
you are still searching
How to:
#1: Check the citations to keep
#2: Use the Send pull-down menu to select
Clipboard
#3:Click on Send.
Will keep up to 500 records for 8 hours!
73. 73
Are there other
ways to limit your search?
Add additional terms to query box
copd air pollution
Use Boolean Connectors
AND, OR, NOT
74. 74
Combination Searching
Let us use the search:
“I am looking for an article from a few years
ago (maybe 4-5 years ago) by Dr. Keys
about cervical cancer treatment.
It was published in the New England
Journal of Medicine.”
75. 75
Combination Searching
PubMed uses Automatic Term Mapping
and maps the search terms as:
keys keys[All Fields]
cervical cancer "cervix neoplasms" [MeSH
Terms]
new england journal of medicine "N Engl J
Med"[Journal]
76. 76
Advanced Searching
Let us use this search:
“My neighbor had a stroke.
I understand that Dr. Chin has done
research on the neurological aspects
of this and it was published in the
journal Neurology.”
77. 77
Preview/Index tab
Preview the number of search results
before displaying the citations
Refine searches by adding one or more
terms one at a time
Add terms to a strategy from specific
search fields
We are thankful to new technology – it has provided information within secondsRECORDS - to set down in writing , a written & permanent evidence or an authentic official copy
FILE - a collection of papers or publications, related data records usually arranged or classifiedDATA -facts or information used usually to calculate, analyze, or plan something
the cross-over occurred in 2008, when more Internet access devices were mobile phones than personal computers. In many parts of the developing world, the ratio is as much as 10 mobile phone users to one PC user
A study conducted by JupiterResearch anticipates that a 38 percent increase in the number of people with online access will mean that, by 2011, 22 percent of the Earth's population will surf the Internet regularly. The report says 1.1 billion people have regular Web access.
fig 6: Publications percent in Medical & Hospitals of different countries ( Medline Database). Fig 7: Publications percent in Universities of different ...
Fig 2: Trends for Number of Publications (Medline-Database) for different Countries. Institutional distribution of biomedical knowledge
PubMed (pubmed.gov) is a free resource developed and maintained by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine® (NLM).PubMedProvides free access to MEDLINE, NLM's database of citations and abstracts in the fields of medicine, nursing, dentistry, veterinary medicine, health care systems, and preclinical sciences.Links to full-text articles found in PubMed Central or at publisher web sites, and other related resources.Provides Advanced search, Clinical Queries search filters, and Special Queries pages.Links to related articles and provides discovery tools for other data that may be of interest.Includes automatic e-mailing of search updates, the ability to save records, and filters for search results using "My NCBI".Includes a spell checker feature.Links to NCBI molecular biology resources.Adds citations Tuesday through Saturday.In addition to MEDLINE citations, PubMed also contains:In-process citations that provide a record for an article before it is indexed with MeSH® and added to MEDLINE or converted to out-of-scope status.Citations that precede the date that a journal was selected for MEDLINE indexing.Some OLDMEDLINE citations that have not yet been updated with current vocabulary and converted to MEDLINE status.Citations to articles that are out-of-scope (e.g., covering plate tectonics or astrophysics) from certain MEDLINE journals, primarily general science and general chemistry journals, for which the life sciences articles are indexed with MeSH for MEDLINE.Citations to some additional life science journals that submit full-text articles to PubMedCentral® and receive a qualitative review by NLM.Citations for the majority of books and book chapters available on the NCBI Bookshelf.
MEDLINEMEDLINE is NLM's bibliographic database of citations and abstracts, currently from more than 5,600 biomedical journals published in the United States and worldwide. Coverage extends back to 1946.All citations in MEDLINE are assigned Medical Subject Headings (MeSH®) from NLM's controlled vocabulary to assist users in their searches.For additional information on MEDLINE see the MEDLINE/PubMed Resources Guide.
PubMed provides access to MEDLINE, the National Library of Medicine’s premier bibliographic database containing citations and author abstracts from approximately 5,200 biomedical journals published in the United States and in other countries. The scope of MEDLINE includes such diverse topics as microbiology, delivery of health care, nutrition, pharmacology and environmental health. The categories covered in MEDLINE include everything from anatomy, organisms, diseases, psychiatry, and psychology to the physical sciences. MEDLINE currently contains over 17 million references dating back to 1948.New material is added Tuesday through Saturday.Coverage is worldwide, but most records (about 90%) are from English-language sources or have English abstracts.Approximately 79% of the citations are included with the published abstract.
A sample MEDLINE citation from PubMed follows.
The ThesaurusMeSH is the National Library of Medicine's controlled vocabulary thesaurus. It consists of sets of terms naming descriptors in a hierarchical structure that permits searching at various levels of specificity.MeSH descriptors are arranged in both an alphabetic and a hierarchical structure. At the most general level of the hierarchical structure are very broad headings such as "Anatomy" or "Mental Disorders." More specific headings are found at more narrow levels of the twelve-level hierarchy, such as "Ankle" and "Conduct Disorder." There are 27,149 descriptors in 2014 MeSH. There are also over 218,000 entry terms that assist in finding the most appropriate MeSH Heading, for example, "Vitamin C" is an entry term to "Ascorbic Acid." In addition to these headings, there are more than 219,000 headings called Supplementary Concept Records (formerly Supplementary Chemical Records) within a separate thesaurus.MeSH ApplicationsThe MeSH thesaurus is used by NLM for indexing articles from 5,400 of the world's leading biomedical journals for the MEDLINE®/PubMED® database. It is also used for the NLM-produced database that includes cataloging of books, documents, and audiovisuals acquired by the Library. Each bibliographic reference is associated with a set of MeSH terms that describe the content of the item. Similarly, search queries use MeSH vocabulary to find items on a desired topic.Establishing and Updating MeSHThe Medical Subject Headings Section staff continually revise and update the MeSH vocabulary. Staff subject specialists are responsible for areas of the health sciences in which they have knowledge and expertise. In addition to receiving suggestions from indexers and others, the staff collect new terms as they appear in the scientific literature or in emerging areas of research; define these terms within the context of existing vocabulary; and recommend their addition to MeSH. Professionals in various disciplines are also consulted regarding broad organizational changes and close coordination is maintained with various specialized vocabularies.MeSH DataMeSH, in machine-readable form, is provided at no charge via electronic means. The MeSH Web site http://www.nlm.nih.gov/mesh is the central access point for additional information about MeSH and for obtaining MeSH in electronic form.
Creating a questionCreating a well-focused question is the first step in a literature search. Having a clear idea of what you are researching will keep you on track with your searching, saving you valuable time. A focused question will give you a better start with your search because it will help you determine appropriate keywords and limitations for your topic.When forming your question, make sure you are specific about your research topic. Things to consider are: The type of patient; The condition or situation you are researching; The type of intervention or nursing procedure you are investigating.This is a good time also to determine limitations to your search, such as: How many years you want to go back in the literature; you may want to limit the years to make the search more manageable or clinically up to date, while capturing key information for your research.; Language: are you limiting the search to sources in the English language? Geographical specifity, for example, limited to the UK or EU or to include international literature.
Creating a questionCreating a well-focused question is the first step in a literature search. Having a clear idea of what you are researching will keep you on track with your searching, saving you valuable time. A focused question will give you a better start with your search because it will help you determine appropriate keywords and limitations for your topic.When forming your question, make sure you are specific about your research topic. Things to consider are: The type of patient; The condition or situation you are researching; The type of intervention or nursing procedure you are investigating.This is a good time also to determine limitations to your search, such as: How many years you want to go back in the literature; you may want to limit the years to make the search more manageable or clinically up to date, while capturing key information for your research.; Language: are you limiting the search to sources in the English language? Geographical specifity, for example, limited to the UK or EU or to include international literature.
Creating a questionCreating a well-focused question is the first step in a literature search. Having a clear idea of what you are researching will keep you on track with your searching, saving you valuable time. A focused question will give you a better start with your search because it will help you determine appropriate keywords and limitations for your topic.When forming your question, make sure you are specific about your research topic. Things to consider are: The type of patient; The condition or situation you are researching; The type of intervention or nursing procedure you are investigating.This is a good time also to determine limitations to your search, such as: How many years you want to go back in the literature; you may want to limit the years to make the search more manageable or clinically up to date, while capturing key information for your research.; Language: are you limiting the search to sources in the English language? Geographical specifity, for example, limited to the UK or EU or to include international literature.
The Details tab shows you how PubMed translated your search terms