New England Region National Network of Libraries of Medicine June 2004

What is PubMed? The world’s premiere biomedical bibliographic database Online access to the MEDLINE database Developed & maintained by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine (NLM)

Contains citations to journal articles in these major content areas: Biomedical Sciences Nursing Dentistry Veterinary Medicine Pharmacy Allied Health Preclinical sciences

PubMed also contains information on Health policy Bioinformatics Health administration Standards and practice guidelines Health-related technology Patient education materials and consumer health information

PubMed contains: 14+ million bibliographic citations 1950s – present 4,600 journals published worldwide are indexed 50+ languages represented Some freely available full text documents Some full text books Links to the other NCBI databases

Accessing PubMed on the Internet: PubMed is freely available wherever there is internet access. No registration. No subscription. No fees. No kidding. The next slide shows the homepage of PubMed.

Part 1: Basic Information and Navigation Very basic searching that works Results What do those icons mean? What’s a citation? In what order are search results displayed? How can I display and sort my results? What can I do with my results?

Type ‘n Go searching of PubMed: Simply type a term or terms in the Search Box and click Go.

Note that “and” is the default connector used in PubMed. If more than one term is entered into the search box, PubMed will AND the terms together. To use AND as part of your search, type it in CAPITAL letters. This should be done for all connecting words: AND, OR, NOT

Results = a list of citations meeting the search criteria displayed in Summary format

What’s in a citation? Author names. Click to access abstract. Title of the journal article Journal title abbreviation and publication information The PMID is like a Social Security number for a citation. It is a unique identifier for the citation. This tag indicates the level of processing this citation has received. This particular citation has been fully processed. This icon indicates this citation has an abstract. Clicking on the icon will bring up the abstract.

Icons that appear in the Summary Results: No abstract available for this citation. This citation has an abstract. There is free full-text access to this article. There is free full-text access to this article through PubMed Central (PMC), an initiative from the National Library of Medicine to encourage publishers to make their content freely available.

About abstracts: Some citations have them, some do not. If an abstract appeared in the print publication, there will be an abstract in PubMed. Abstract length varies: some are very short; some are quite lengthy To see the abstract, click on the author name or the icon in the Summary Format.

More on results. Here is a search for childhood immunization refusal

More about results Some article titles are in brackets. Why? Some articles have no authors listed. Why? Brackets indicate the article is published in a language other than English If no authors are listed in PubMed, it’s because no authors were listed in the print version of the article.

Summary format: this is the default format for displaying results in PubMed. Showing 20 items per page Number of results for this search Number of pages of results The Action Bar

Other searches may produce many more results, still in Summary format, on many pages. Move from one page to the next by clicking on Next Or, move many pages at a time by putting a number in the box next to Page and then clicking on the Page button. The way information displays on the page may also be altered.

Other Display Formats are available: To change from one display option to another, simply highlight the desired format and then click Display. Different formats are useful for different reasons. The Abstract format will show the abstract (where available). The Citation format will show the abstract (if available) as well as the MeSH terms used to index the citation.

In what order are search results displayed?

Results are displayed in Entrez date order The citation that: was most recently added to the database and meets the search criteria will be displayed first. It is possible to sort citations into order by publication date.

Sorting results Sort options: -the first author’s last name -the title of the journal -the publication date of the article. Select the desired sort option by highlighting it Click Display to make the sort happen.

When searching is complete, what can be done with the results? Citations may be printed, ed, or saved in various ways Use the Send To options:

First, select citations: Click the box next to the citation Have several pages of results? That’s OK. PubMed will keep track of your selected citations as you move from page to page.

Now, choose the Send to option: Highlight the desired option Click Send to

Send to “Text” strips away graphics:

Send to File saves the selected citations as computer files Send to Clipboard places the selected citations on PubMed’s Clipboard Send to allows users to citations Send to Order allows users with Loansome Doc accounts to request copies of selected articles electronically

CAUTION: If you do not select citations but choose a Send To option, you are selecting all the citations in a given result set Up to 500 citations  will be added to the Clipboard Up to 10,000 citations  will be saved in a computer file All the citations on a single page  will appear in text only format

Clipboard: Holds selected search results Select citations. Highlight Clipboard. Click on Send to.

When citations are added to the Clipboard: A pink banner confirms the addition The number of each selected citation turns green

Clipboard holds selected search results Those citations stay on the Clipboard until: The user manually removes them –or- There are 8 hours of inactivity on that computer. Close the PubMed browser, shop for airline tickets, read the Globe online, then open PubMed again -- the Clipboard items will still be there, provided there have not been 8 hours of inactivity on that computer.

Accessing the Clipboard Click on the word Clipboard under the search box

This is the Clipboard:

Once in the Clipboard, the usual Send to options are there along with a new one: Use this to remove items from the Clipboard. Select item, highlight Clip remove, click Send to.

Send to Select Format and Sorting options Add a note if desired Insert address Click Mail

A word about and PubMed The sender for s sent from PubMed will be “Sent by Entrez.” Since we’re the only ones who know what that means, your could easily get deleted. RULE OF THUMB: send s to yourself first and then forward them on to colleagues. That way, your name will appear as the sender.

Review Searching Type and Go: the simplest form of searching Changing the way information displays on the page The Action Bar: display, show, sort Selecting citations Save / print / citations Using the Send To options

Part 2: The Inside Scoop More on Type ‘n Go searching Using Limits to focus a search The devil’s in the details MeSH Citations & Levels of processing Automatic Term Mapping History, Related Articles, and finding free full text in PubMed How to learn more

One way to narrow a broad search is to add additional terms to the search. For example, searching for citations about smallpox vaccine? Type both words into the search box: It’s still Type ‘n Go.

Practice Searching In Dec. 2002, newspapers reported that indoor hot tubs may be making people sick with a respiratory ailment. What’s in PubMed about this? Your search?

Fall 2002, NPR reported that a physician was claiming that duct tape could get rid of warts. Can you find information in PubMed on this topic? Your PubMed search?

Returning to that search for smallpox 6,800+ results are way too many to deal with. Reduce retrieval and focus results using Limits: Access the Limits screen by clicking the word Limits under the search box.

Using Limits can significantly reduce the number of items retrieved. Use it to focus a search. Some of the most popular limiters are: Language Publication Type Date of publication

Language selections Publication type selections

To apply Limits to a search: Highlight the desired options from the drop-down menus. One or many options may be chosen. Click Go to run the search with the chosen limits

Search results using Limits: PubMed clearly shows which Limits have been applied.

It’s just as simple as that. PubMed is deceptively simple to use and yet very sophisticated. The devil’s in the details.

The major details: What’s the organizational structure of this database? How does PubMed search?

Indexing allows efficient retrieval of relevant information from a database. MeSH is the controlled vocabulary used for indexing citations in PubMed. MeSH  Medical Subject Headings

The Citation Format displays the MeSH terms associated with a given indexed citation

How can I find out if a given term is a MeSH term? Use the MeSH Database Click on the link from the blue sidebar

PubMed’s MeSH Database:

The MeSH database allows searchers to look up terms and build searches. These animated tutorials teach searchers how to use the MeSH database. They are available on the MeSH Database page. Each takes only moments to view.

Types of citations in PubMed: [PubMed – as supplied by publisher] [PubMed – in process] [PubMed – indexed for MEDLINE] [PubMed – OLDMEDLINE for pre-1966]

Why would searchers want to know the different types of citations in PubMed? Only [PubMed – indexed for MEDLINE] citations have been indexed with MeSH terms. These citations will be retrieved by doing a MeSH term search. All the other citation types have no indexing attached to them. These citations will not be found by a MeSH term search.

OK, so MeSH is the organizing principle behind PubMed If I don’t know MeSH, can I still get good results searching PubMed? Yes! Why?

Automatic Term Mapping: The 3 steps PubMed goes through every time a search is executed 1. MeSH 2. Journal Title 3. Author

The Details Box Look at Details to see what PubMed did with your search terms

Check the DETAILS box! PRACTICE SAFE SEARCHING

Search “measles” and the Details box shows the actual search run by PubMed :

Automatic Term Mapping has mapped the word to its appropriate MeSH term(s) Note that text words have also been added to the search. Why? To help retrieve those non- indexed citations mentioned earlier. If a user types in a non-MeSH term as a search term, what happens?

Here’s how “drooling” is mapped:

Step 1: PubMed looks for a match with a MeSH term. If a match is found, PubMed uses that MeSH term and runs the search. If no MeSH match is found, Automatic Term Mapping moves to step 2: looking for a match with a journal title. If a match is found, PubMed uses that title and runs the search. If no match is found with journal titles, it’s on to step 3: looking for a match with author names.

Step 2: Searching for a journal title

Check the DETAILS box! PRACTICE SAFE SEARCHING

Since “New England Journal of Medicine” is not a MeSH term, PubMed finds no match. So, it moves to the 2 nd step: journal titles. And there it finds a match!

So, citations from journals may be retrieved by typing in the name of the journal or the MEDLINE abbreviation for the journal in the search box. Find all the citations from the journal “Chest” Your search?

Oops. What happened?

Check the DETAILS box! PRACTICE SAFE SEARCHING

Chest maps to the MeSH term, “thorax.” PubMed didn’t even get to the 2 nd step!

Tell PubMed what field to search. This turns off Automatic Term Mapping

Now, PubMed is no longer mapping the term. It is simply searching the field it has been directed to search.

Step 3: Author Searching Format for author names in PubMed: Last Name Initial(s) NOTE: there is no punctuation between last name and initials

A note on Phrases: PubMed does NOT do any proximity searching or adjacency searching, but it can “read” – recognize – many phrases. Using quotation marks around a phrase will force PubMed to do phrase searching, but if it cannot “read” the phrase, Automatic Term Mapping will be applied. It is recommended that terms be searched with no quotation marks first.

Truncation The asterisk * is the truncation symbol Only end-of-word truncation is allowed in PubMed Cardio* is allowed Col*r is not allowed *megaly is not allowed Truncation turns off Automatic Term Mapping

Using truncation, search for all the variations of the term handwash

Check the DETAILS box! PRACTICE SAFE SEARCHING

Sometimes, a truncated search will prompt a cautionary message in PubMed:

Additional details: Boolean searching is allowed: AND, OR, NOT + or – signs not allowed Nesting – using parentheses – is allowed Combining words MUST be in all CAPITAL letters

So, we’ve talked a bit about the major details: What’s the organizational structure of this database? How does PubMed search? What else is there?

Searches may be constructed using the: Search box: Type and Go. Highly recommended. MeSH database: see animated tutorials on the MeSH database page. History function

History Keeps a record of searches performed Rerun searches Delete searches View the Details Box for a selected search Combine previous searches to make new searches Access History by clicking on the blue word History under the search screen

History remains until there are 8 hours of inactivity or until the searches are manually deleted from History. The Clear History button will delete everything in History.

Each of the query numbers is hyperlinked. Click on the query number and a menu will appear:

Combine searches using AND, OR, or NOT Erase this specific search from History using Delete Return to this search using Go See the Details Box for this search using Details

To find information about smallpox and bioterrorism Click on the search number for smallpox, highlight AND Click on the search number for bioterrorism, highlight AND Click Go at the right side of the search box to run the search.

Two final thoughts on searching PubMed 1. The Related Articles link: Find one article you like, click Related Articles and PubMed will do a search for similar articles. Read about the algorithm for this related articles search in PubMed’s Help

2. Finding free full text in PubMed This search, alone or ANDed with other terms, will limit results to only those articles that have free full text available: Caution: Using this as a limiter will greatly reduce retrieval. It’s useful in a pinch, but should be used with caution. Freely available full text is a very, very small slice of the PubMed pie.

Other capabilities of PubMed Journals Database Single Citation Matcher LinkOut Cubby

So, you want to learn more? Overview Tutorial Help & FAQ New/Noteworthy

Animated tutorials are on how to use the Cubby and how to use the MeSH database are available on this NLM website: There is a PubMed manual available on the web: Contact your regional medical library for information on free training:

Hmmm….. Better write a note to myself to check the Details box in PubMed