The foundation of any search strategy is terms. Your strategy should include both Subject Headings and Keywords.
Subject Headings
- A standardized set of terms (controlled vocabulary) used to describe content in a database. This process is called indexing.
- Example: In Ovid Medline, the subject heading for tumour, cancer, or neoplasm is Neoplasms.
Searching for Neoplasms retrieves all articles indexed under these terms.
- Subject headings vary by database which means search strategies must be customized for each database.
- Ovid Medline / PubMed → MeSH
- Ovid Embase → Emtree
- CINAHL → CINAHL Headings
Keywords
- Words that appear in the resource (e.g., title, abstract, author keywords).
- Useful for capturing:
- Articles not yet indexed
- Articles incorrectly indexed articles
How to Identify Subject Headings and Keywords
- Search for a known article in a database (e.g., PubMed)
- Click on Publication Type, MeSH terms to display the subject headings
- Scan the title, abstract, and author keywords

- Create a concept map
- Search each keyword in a database (e.g. Ovid Medline).
- This will allow you to identify additional subject headings.
- E.g., A search for lateral elbow yields the subject heading Tennis Elbow.

Note: Not all search terms map to a subject heading. If no match exists, search as a keyword. This option is available after the list of subject headings in most databases.