Medical Information on the Internet
PubMed is a specialized search engine, designed to search for full title, author, and publication information (this information is called a CITATION) in medical journals. Search engines like Google and Yahoo do NOT search for this information. In order to locate it, you must use a specialized database like MEDLINE. MEDLINE, which is produced by the National Library of Medicine, lists over 15 million article summaries and is updated weekly.
PubMed is a very flexible search engine, developed to accommodate both simple and complex search strategies. One of the strengths of the MEDLINE Database is the indexing that is at its core. Articles which will be listed as citations in the database are read carefully by expert indexers, who assign a set of specific subject headings to each citation. These subject headings are taken from a carefully developed list of headings, called the MeSH Thesaurus, which ensures that all articles on particular subjects will be found, even if the author of the article did not use the words or spellings which the searcher ordinarily would use.
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Let's demonstrate the use of the MeSH Database. Click on the following link (opens new window) http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=mesh (new window) and type in the phrase "breast cancer". The browser will let you know that the correct term is "Breast Neoplasms," and will provide a definition of the term. Now click on the term "breast neoplasms." Notice that you can limit your search to a number of subheadings, including "therapy", "chemically induced" and "prevention and control". These subheadings provide you with another method of limiting your search results. Select the subheading "chemically induced" and click the "SEND TO" button (with the drop-down showing the selection "Search Box with AND.") Now, select the "Search PubMed" button and you will see the list of articles available on this topic. |
PubMed defaults to a textword search, meaning that it will search ANY occurrence of the search term, whether it is in a subject heading, an abstract, or the title. This can be very helpful in finding information that is not included in a MeSH heading, or to broaden a search to items that only marginally touch on a subject. To begin searching PubMed:
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Go to http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed (new window) and type in "Viagra". The MeSH Database does not know that the generic name of the drug is Piperazines, so by searching for the text word, we can extend the search by next searching for the word "Piperazines". Or, we might know that we need the article to use the exact word "Viagra," in which case we would stay with the original search. The LIMITS link at the top of the screen can be used to further narrow the search results. Click on it. Use the drop down choices to limit to Language (English), Human or Animal (Human), Gender (Female), Ages (Adult, 19-44 years) and hit "GO". Notice that the results number will go significantly down. |
We can also use the "Related Articles" link to get better articles once we discover an article that seems correct.
Look at the results of the "related articles" search, and see how closely they match the original article. Notice, too, the "Limits" you selected are no longer in place. The related articles feature uses an algorithm based on the article you selected, not on your original search, to reach the results you've just seen.
PubMed will also allow you to search for a particular author; HOWEVER, be aware that PubMed does NOT always list the first name of an author.
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Exercise Visit http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed (new window) and we'll search for articles by pediatrician Peri Klass. In the search box, type in "Klass P" and hit "GO". Notice that we get several names that seem relevant: Klass P, Klass PH, Klass PE, Klass PD, etc. |
