An Introduction to PubMedhttp://www.ncbi.nlm.nih.gov/PubMed/
Additional PubMed help is available at
What is PubMed?
PubMed is the National Library of Medicine s search service that provides
MEDLINE: an international bibliographic database of over 4000 biomedical
journals from 1966-present.
PreMEDLINE: new records are added daily; will appear with the tag [MEDLINE
record in progress].
HealthSTAR: a health administration and technology/research database; also
includes full text of practice guidelines.
PubMed also provides links to molecular biology databases of DNA sequences, population
data, and genomes.
PubMed may be searched by entering keywords or phrases into the text
box. You may enter one or more terms and press the enter key or click Go.
PubMed will search multiple words as a phrase if it recognizes the terms. Otherwise, PubMed
will search the words separately and combine with AND. PubMed will also
automatically try to map your term to a MeSH heading.
Example: vitamin c common cold is searched as vitamin c AND common
PubMed does not perform adjacency searching; instead it uses a Phrase List against which to
match terms. Enclosing a term in quotation marks forces PubMed to check a second Phrase List.
If the term is still not found, the words are combined with AND.
When using keyword searching, you may sometimes want to truncate (*) words to allow
for variant word endings.
Example: bacteri* retrieves bacteria, bacterium, bacterial, etc.
Medical Subject Headings (MeSH)
Using MeSH can help you achieve specificity in results and may be the most
precise way to do Subject searches. Articles are entered into MEDLINE using the Medical
Subject Headings, NLM's controlled
vocabulary for indexing articles. MeSH terminology provides a consistent way to retrieve
information that may use different terminology for the same concepts.
One way to identify and select MeSH terms for a search is to use the
Index feature found on the function bar below the text box. Click Index, pull
down the All Fields menu, select MeSH Terms, and enter the term in the
View Index text box. Click View. To select more than one term, hold down
the Control key and click on each of the terms you wish to include and click on
OR to place all terms in the text box. MeSH Subheadings, which restrict a
term to a specific aspect, may also be selected here.
Example: asthma/chemically induced
HINT: Subheadings are useful common categories
such as diagnosis, drug therapy, etiology, prevention and control, surgery, which
can help to limit your search. The use of subheadings might sometimes eliminate some useful
Another way to select MeSH terms is to use the MeSH Browser
link, found on the blue sidebar, which allows you to browse for appropriate terms. Enter the
term in the text box and click GO.
Scroll down the page to see everywhere the term appears in the MeSH "Trees", a hierarchial
subject category display of Mesh terms. For
example, if you browse this list for diabetes, you can select from a host of terms
including diabetes mellitus, obesity in diabetes, diabetes mellitus insulin dependent, or
To further refine your search click on Detailed Display:
MeSH Subheadings, which restrict a term to a specific aspect, may be selected
Check Restrict Search to Major Topic headings only to focus your search to those
documents in which your term is considered the major point of the article.
Check Do Not Explode this term to not include MeSH terms found below your
term in the MeSH tree.
If you know the Medical Subject Heading you may enter it directly into
text box. Click on Limits, pull down the All Fields menu and select
MeSH Terms or MeSH Major Topic.
HINT: Limiting to MeSH may eliminate PreMEDLINE citations
because these articles have not yet been indexed.
Limiting a Search
Limits allow you to search specific fields using pull-down menus for
Publication Type, Language, Subsets, Ages, Human/Animal, Gender, and Date.
Click on the word Limits below the text box.
- Publication Type is an especially important limit in that it acts as a filter in finding
studies/literature of a certain type or methodology. For example, the diabetes drug therapy
search when limited to Randomized Controlled Trial will retrieve high-level studies
more likely to have clinical relevancy. The same search limited to Review will retrieve
tutorial or literature reviews.
- Subset is another powerful limit which allows users to limit retrieval to subsets
within the MEDLINE database such as AIDS, AIM (Abridged Index Medicus), Nursing.
AIM limits retrieval to a subset of about 120 core clinical journals -- compared to the nearly
4,000 in the MEDLINE database!
- Only Items with Abstracts limits your search to only those articles which have
abstracts. This is an easy way to eliminate letters, editorials, or commentaries.
You can click on Limits at any point in your search to apply, drop, or change the
limits. A check mark in the box next to the Limits indicates that limits are active for
HINT: Unless changed or unless the check mark is turned off, limits
remain active for an hour. If you start a new search, make sure to refresh the limits!
Combining Concepts: The Search History
Continue to add terms to your search until you have entered all the concepts (clear the
text box before entering a new concept). Or you may enter the concepts separated by
search operators as illustrated below.
The History function keeps track of your searches and numbers them, allowing you
to go back to earlier searches and combine or modify them. The History button is
found on the function bar under the text box.
HINT: You must use the # symbol before the search
numbers and search operators (AND, OR, NOT) must be
AND Articles containing all of the terms you selected. AND narrows your
Example: #1 diabetes mellitus non-insulin dependent/drug therapy
#2 oral agents
#1 AND #2
OR Articles containing one or any of the terms you selected. OR
broadens your retrieval.
Example: hay fever OR asthma
Example: (heat OR humidity) AND multiple sclerosis
NOT Use NOT to eliminate terms or sets you do not wish to appear in
Example: asthma therapy NOT child
Title Word Search
Limiting a search to a word found in the title is often a good way to reduce large search
results. You can do this by entering the term in the text box. Then click on Limits,
pull down the All Fields menu, and select Title Word.
You may also limit to title by entering the term followed by [ti].
Example: non-Hodgkins lymphoma [ti]
To retrieve articles by author, enter the author's name in the format of last name
followed by initials.
Although initials are optional, search retrieval may be quite large (and inaccurate) without them,
especially for common last names. Click on Limits, pull down the All Fields
menu, and select Author Name. Or follow the name with [au] as shown
below. The Index provides a list of author names and variations.
jobe [au] (585 hits)
jobe p [au] (105 hits)
jobe pc [au] (102 hits)
Related Articles Feature
A helpful PubMed feature is the ability to find documents that are similar to a
document which you find of interest. To retrieve related articles for a given record, click on
Related Articles, which appears at the right of each citation.
The Related Articles will display in relevancy rank order, becoming less relevant the further
down you progress in the display. Limits are disregarded by the Related Articles function. For
example, foreign language articles will appear even if your original search was limited to English
The Related Articles feature is a good way to discover synonymous/related concepts that you
may not have considered in your original strategy. Examine the MeSH terms (use the
Citation display) to look for alternative or additional MeSH terms to use in a modified
The Clinical Queries search mode is designed with clinicians in
mind. It works only for diagnosis, etiology, therapy and prognosis questions. Built-in search
"filters", tested by the EBM Working Group at McMaster University,
screen for clinical relevancy.
The "Table for Clinical Queries
Using Research Methodology Filters" outlines the filters used for each of these four categories.
The objective of Clinical Queries is to
reduce retrieval to articles that report research conducted using specific methodologies.
For example, a therapy search will retrieve randomized controlled trials and a
diagnosis search will retrieve studies which employed sensitivity and specificity
criteria. If you wish to retrieve everything on a subject, you should not use this search
The Citation Matcher feature allows you to find/verify citations
using bibliographic information such as journal name, volume, issue, page number, publication
year, or author. This feature is especially helpful when you have incomplete bibliographic
If you enter only the Journal Name, you will get a "Table of Contents" type listing starting
with the most recent issue of the journal.
This can serve as a current awareness service.
Displaying Search Results
PubMed displays search results in batches; the default is 20 records per page. To
change the default, the Show pull-down menu allows you to increase the number of
records displayed on a single page up to 500. This is convenient when you wish to browse the
entire display to choose selected articles to save or print.
PubMed citations initially display in Summary (Author, Title, Journal, PubMed
ID) format. Documents can be viewed in other formats including Brief (author,
PubMed ID), Abstract (Author, Title, Journal, PubMed ID, Abstract), Citation
(Author, Title, Journal, PubMed ID, Abstract, MeSH Headings), and
MEDLINE (for importing into citation software - Author, Title, Journal, PubMed ID,
Abstract, MeSH Headings).
Display by clicking on the author s name. This causes PubMed to display the Abstract
Select a display format and then click Display to view a different display for
all citations on a page.
Click on the boxes to the left of each author name to select specific citations, then select
a format from the Display menu and click Display.
Printing Search Results
Once search results have been Displayed in the desired format
(Summary, Brief, Abstract, Citation, or
MEDLINE), click on the Print icon on your browser to print the results.
Saving Results to
Results may be saved to a disk or hard drive. Once search results have been
Displayed in the desired format (Summary, Brief,
Abstract, Citation, or MEDLINE), click on the Save
button next to the Display pull down menu.|
A "Save As" Dialog Box will appear. Title the name of your search in the File
Name Box. Click Save. These files can be opened in Word, WordPerfect, or
Saving to Citation Software (Reference
To import results into Citation Software, you must display your results in
MEDLINE format. Click on the Save button next to the Display pull down
menu. Title the name of your search in the File Name Box. Click Save.
Saving Search Strategies
Create your search strategy and limit your strategy as desired. When this is complete click on
the Details button. This will display a "behind the scene" look at exactly how your
search strategy was executed.
Click on URL under the PubMed Query Details Box. This will transform your search
strategy into a URL address. Click on Bookmarks on your Web browser and select
Add Bookmark. This will book mark a web address called Entrez-PubMed.
Whenever you want to perform a search on the selected medical topic, simply click on the
Search strategies may be saved in PubMed. This is useful for re-running
searches on a periodic basis to keep up-to-date on topics of interest to you.||
You may want to edit the name of Entrez-PubMed to something meaningful. To do this,
Click on Bookmarks and select Edit Bookmarks. A bookmarks Edit Window
should appear. Click on Entrez-PubMed from the list that appears. Next, under Edit
click on BookMark Properties. In the name text box, change Entrez-PubMed to a
meaningful name for your search. (Do not save strategies created using Search History search
Limiting your strategy to the Last 30, 60 or 90 days. It is possible to limit saved
search strategies to search only the last 30, 60 or 90 days of literature that has been entered. To
do this, click on Limits. On the limits page, select either 30 Days, 60 days, 90 days, 180 days
from the Entrez Date pull down menu.
The Clipboard allows you to group selected citations from one or more
searches. You may then print or save the citations. A maximum of 500 citations can be placed in
the Clipboard. Clipboard items will be lost after one hour of inactivity.
To add items to the clipboard, click on the check box to the left of the citation and
then click Add to Clipboard. Once a citation has been added to the Clipboard, the record number
color will change to green.
Once you have added items to the Clipboard, you can click on Clipboard from the Features
bar to view your selections. In the Clipboard, you can sort citations by author, journal, or
publication. Click on the Clipboard Sort pull-down menu to select a sort
field. Next click on
PubMed is gradually adding links to various publisher sites where users may
immediately access the full text of selected citations. Most online journals require a
subscription. UIC subscribes to numerous online journals which may be accessed through
Once your search is complete, click on LinkOut in the Display pull down
menu. This will show a brief display of the articles and available link outs. LinkOuts for Karger,
Ideal, MDConsult, Blackwell Science, or Elsevier will let UIC users link directly to the article._
Click on the linkout icon that appears in the search display to access the article.
In order to link to these online journals you must be dialing in through UIC, using a UIC
ethernet connection, or have the Bluestem proxy set on your computer.
Special Instructions for MDConsult and Science Direct articles:
In order to access MDConsult articles, you must set up a personal edition
through UIC at http://home.mdconsult.com/groups/uic.html. There is no charge for this special
feature When you click on MDConsult in PubMed, you will be prompted for a user name and
password. Use your MDConsult personal edition account information.
In order to access Science Direct articles - you must first click on Elsevier and
click on Science Direct.
- Many important journals are still only available in print format.
- Most journal articles written prior to 1996 will not be available online.
- You must search Ovid MEDLINE in order to link directly to the 204 journal titles
subscribed to through Ovid.
J. Dorsch / S. DeGroote 07/00