Exploring Ovid MEDLINE

Ovid MEDLINE is a commercially licensed version of the MEDLINE database, the U.S. National Library of Medicine's premier database of biomedical literature. It is substantially the same as PubMed, the free version of MEDLINE, but with a unique search interface.

MEDLINE covers the journal literature in all areas of biomedicine, including medicine, nursing, allied health, health administration, and bioethics, plus the "pre-clinical" sciences such as biochemistry, microbiology, and genetics. It provides citations, abstracts, and often links to the full text of journal articles.

The MEDLINE database is based on a controlled vocabulary called the MeSH (Medical Subject Heading) thesaurus, in which each term is referred to as a "MeSH term".

MeSH terms can be thought of as search tags that are applied to each article in the database to describe their content. Searching with MeSH headings results in a more focused and efficient search because it automatically finds articles using synonyms, acronyms, and alternate spellings for the term being searched.

The unique design of the Ovid search platform take the guesswork out of constructing search strategies by helping you to find the MeSH terms that most closely match your topic. It then creates a separate set of results for each term, enabling you to mix and match sets to achieve the best results.

The following video will take you through a sample Ovid MEDLINE search in which we search for articles on the use of exercise as a treatment for women with fibromyalgia.

The video will cover:

• Mapping of search terms to official MeSH headings
• The MeSH hierarchy, in which specific terms are nested beneath general terms
• Exploding a MeSH heading
  
• Conducting a keyword search
• Combining sets using the Boolean operators OR and AND
  

The previous video demonstrated how the Ovid system helps you find the most relevant MeSH headings, while also offering an option to search by keyword. Hopefully you can now appreciate the value of generating a separate set for each term, enabling you to mix and match the sets to achieve the best results.

The initial search strategy, which employed both MeSH headings and a keyword, looked like this:

• ((Fibromyalgia [MeSH] OR fibromalgia [keyword]) AND (explode Exercise [MeSH] OR Exercise Therapy [MeSH])

Based on the results, the strategy was later simplified to use just two MeSH headings:

• Fibromyalgia [MeSH] AND Exercise Therapy [MeSH].
  

The next video will explore the use of limits (or "filters") to both reduce the overall number of results and to create a more focused set. Once you've done that, you'll be ready to review the results, and proceed to finding the full text of the articles.

1. If your search brings up too many results, which of the following strategies could be used to reduce and focus the number of results?

a) "Explode" the original term to include articles indexed with more specific terms

b) Limit results by sex or age group

c) Limit results to a particular publication type, such as review articles

d) Search on a more general term

e) a and d

f) b and c

g) a, b, and c

h) all of the above

2. If your search brings up too few results, which of the following strategies could be used to increase the number of results?

a) "Explode" the original term to include articles indexed with more specific terms

b) Limit results by sex or age group

c) Limit results to a particular publication type, such as clinical trials

d) Search on a more general term

e) a and d

f) b and c

g) a, b, and c

3. If you want to combine the results from a MeSH heading search with the results from a keyword search for the same concept, which Boolean operator should you use?

a) AND

b) OR

Dana Medical Library, University of Vermont

Burlington, VT, USA

(802) 656-2201

1. f) applying any type of "limit" will have the effect of reducing the total number of results

2. e) both exploding a term and searching on a more general term will generally increase the number of results

3. b) OR, because you want all articles that satisfy either criterion.