HomeMedline: Navigating the Maze
What is MEDLINE
The National Library of Medicine produces the MEDLINE database. It is widely recognized as the premier source for bibliographic and abstract coverage of the biomedical literature. It indexes more than 11 million article records from more than 4,600 journals.
STRENGTHS: Despite the proliferation of new evidence-based medicine information sources, there is still a need to know how to search MEDLINE efficiently. There will be many times when EBM-specific databases will not locate the information you need. MEDLINE's strengths include its large size, currency of the information (Pre-MEDLINE), coverage of the non-therapeutic literature, and historical information.
WEAKNESSES: The MEDLINE search interface is more powerful than most databases, but search techniques and filters need to be learned for efficient searching. It is also more time consuming to use, because the burden of analyzing and interpreting the article's relevance to clinical care is up to the searcher. It may be necessary to read an entire article before evaluating its usefulness in decision-making and application in the patient care setting.
Searching MEDLINE
The best way to achieve good search results in MEDLINE is to use a search strategy that takes advantage of the wonderful controlled vocabulary of Medical Subject Headings (MeSH), subheadings that are pre-assigned to each MeSH term, and the ability to limit subject search results further by publication type (e.g., meta-analysis) and/or methodology (e.g., clinical trials).
Textword searching (also known as Keyword Searching) is another way to search MEDLINE without the use of the controlled subject headings (MeSH). Textword searches look for the word or words in the Title and/or Abstract fields of the MEDLINE record. Textword searching works best when there is not an appropriate subject heading that describes your specific search concept. Textword searches only find matches on the exact word(s) you type in; so you will want to truncate the word as appropriate to broaden your possible retrieval.
For example, there is not a MeSH term for the concept predisposition. So when doing searches on the etiological aspect of a condition, you may want to search predispos$" (the $ or : can be used to truncate) as a textword. This would locate articles that have the words predisposition or predispose or predisposed in the titles or abstracts.
For help in searching Ovid's version of MEDLINE, please see UVa's guide, "MEDLINE: The Magnificant 7 Search Steps" (PDF).
PubMed
The National Library of Medicine (NLM) creates the MEDLINE database, but there are several search interfaces to MEDLINE available from commercial vendors, such as Ovid and MD Consult. MEDLINE/PubMed and MEDLINEplus are two of NLM's own free search interfaces to the MEDLINE database and other sources of government information.
In addition to including PREMEDLINE (a segment of MEDLINE that provides basic citation information and abstracts before the full records are prepared and added to MEDLINE), PubMed also offers searchers the opportunity to apply proven clinical filters to their searches. These clinical filters are a way to reduce search retrieval to articles relating to four types of clinical research - diagnosis, etiology, therapy and prognosis. There are also options to direct the emphasis of your search to be more sensitive or more specific. Another nice feature of PubMed is the ability to link to Related Articles.
For help in searching PubMed, please see NLM's excellent "how-to" PubMed Tutorial .
To try Ovid's version of MEDLINE, go to http://gateway.ovid.com and enter:
ID = uvademo
PASSWORD = knowhow
This Free code is courtesy of Ovid Technologies, and will be active
through April 24th, 2003.
