Key Ideas > Truncation > Phrases > Boolean Logic > Subjects/Descriptors > Review and Refine > Limiting > Citation Indexes

Generally called "subjects" or "subject headings" in catalogues and "descriptors" in databases, these are: 

• 'Super keywords'
  • Allow the most comprehensive results with fewest irrelevant results
• Controlled vocabulary
  • Use standardised terms
• Often improve search results
  • Constructed via human input or computer algorithms
  • Overcomes differences in describing ideas, not dependent on variations in terminology among writers and across regions and time periods

Unfortunately, the controlled vocabularies vary from database to database. To find the correct ones:

1. Search using keywords you already have
2. Identify relevant records, and check record details
3. Note subject terms
4. Incorporate subject terms in a new search statement
   • In all databases, using subject terms in a general-keywords search option will improve results
   • In some databases, it may help to focus the search by choosing the subject search option