Databases such as Medline (Ovid), rather than relying solely on terminology use a thesaurus of standardised, preferred indexing terms to describe the content of each article; these terms are known as Subject Headings or MESH Headings. NLM indexers examine articles and other publication types and assign the most specific MeSH headings that appropriately describe the subject discussed and when searched, the database will try and match or ‘map’ your topic to the closest matching Subject Heading in their thesaurus.
To Search:
By default the database should open at the Advanced Search option.
Enter your search term(s) in the search box, ensure that the Keyword search option has been selected and that the tick is displayed in the checkbox next to Map Term to Subject Heading. Click on Search as illustrated below:
The database maps your search term(s) over to the preferred terminology, the MeSH heading, used in the database to describe this topic. In this example heart attack is mapped over to the Medical Subject Heading Myocardial Infarction . Be sure to check the scope note to ensure that your understanding of the term, and the databases' description of the term match.
Explode feature
Exploding a MeSH heading will:
To view these narrower, more specific terms click on the Subject Heading:
Below is the "tree" for Myocardial infarction - if you explode the term, all of the indented terms below it will also be searched automatically:
Focus feature
You can use the Focus feature to limit your search to those documents in which your MeSH heading is considered the major point of the article. This will reduce the number of records found.
Searching the chosen MESH term:
To begin the search, click on the Continue button:
Tick the checkboxes next to those subheadings you wish to select. If you do not wish to limit to a specific subheading or aspect of the topic you should tick the Include All Subheadings checkbox:
Results
By clicking on Search History you can see how many resources have been retrieved for that MESH term search and display the results:
Don’t worry if you are having problems using the database; just contact a member of the Life and Health Sciences subject team who will be happy to help. You can also email us at library-lhs@ulster.ac.uk