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Database Search Tips

What are keywords and subject headings?

Keywords are words or phrases that can appear anywhere in the item (citation data or full text of a book or an article). Keyword searching is how you typically search web search engines and it is a good start to find relevant subject headings in databases.

Subject headings are formally assigned, standardized set of terms (also called descriptors) within a database to identify the primary topics of a book or an article.

It is not easy to guess which subject headings are used in a given database. For example, you have a keyword "wage gap" in mind but the closest subject headings for this concept is "wage differential" in the ProQuest Dissertations & Theses Global database.

Here are some key points about each type of search:

Keywords Subject Headings
  • natural language words appearing in the item (citation data or full text article) - a good place to start finding subject headings
  • pre-defined "controlled vocabulary" used to describe the content of a book or a journal article in a database       
  • more flexible to search and can combine together in many ways using Boolean operators
  • less flexible to search since you  need to know the exact subject headings
  • database looks for keywords anywhere in the item
  • database looks for subjects only in the subject heading or descriptor field
  • may yield too many or too few results
  • you can also uses subheadings to focus on one aspect of the broader subject term
  • may yield many irrelevant results
  • results usually very relevant to the topic 

When you search a database and do not get the results you expect, Contact us for advice.

How to find subject headings

Keyword searches

  • Start with a keyword search, using words/phrases that describe your topic.

  • Browse the results; choose 2 or 3 items that are relevant.

  • Look at the Subject or Descriptor field and note the subject terms used.

  • Redo your search using those terms.

  • Your results will be more precise than your initial keyword search.

  • Limitations of subject headings: for very new concepts e.g. "illiberal democracy" the databases may not have current subject terms.


  • Look to see if the database has an online thesaurus to browse for subjects that match your topic (check the Help screens).

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