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Researching for Biology Labs: Keywords & Subject Headings

A lab guide for scientific writing and research.

What's The Difference Between Keywords and Subject Headings?

A keyword search allows you to use your own words to describe what you're looking for. Keyword searching is how you typically search the Web using search engines like Google or Bing.

PROS of keyword searching:

  • Quick, easy to brainstorm
  • Good starting point for most types of research
  • Produces good results in certain databases (e.g., Google Scholar)
  • Flexible - allows you to combine terms together in many different ways
CONS of keyword searching:
  • Often produces too many or too few results
  • Results are not always relevant
  • May miss items that use different terms to talk about the same topic.

 

Subject headings describe the content of an item using terms that are standardized across a database. A subject heading search will return all items on that topic in a database.

To find out whether a particular database uses subject headings, look for a link labelled Thesaurus or Subject Terms. Many databases allow you to search or browse their subject headings.

PROS of subject headings:

  • Can be used to focus or expand your search
  • Produces highly relevant results in most databases
  • Returns all items on a given topic in a particular database, regardless of the terminology used in the article itself.

CONS of subject headings:

  • Less flexible than keyword searching (e.g., you may have to combine multiple subject headings to describe your research topic)
  • Subject headings are different every database
  • Can be time consuming

The Thesaurus

There are two ways to find which subject headings to use.

  1. Search by keyword and then examine the first few records to see what subject terms have been applied to those citations.  Then search by those subject terms of interest.
  2. Use a thesaurus to determine an appropriate subject heading.

A thesaurus is an index of subject terms and is helpful in finding out the subject headings used by a given database. 

 A thesaurus is an index of subject terms and is helpful in finding out the subject headings used by a given database.  Usually a thesaurus will include a "scope note" for the various subject headings which explains what kind of works are assigned a given subject heading.  As well, there may be more specific or "narrower terms' suggested or more general or "broader terms suggested.  If there is confusion in how a subject heading is to be used, there may be additional reference made to other subject headings called "see" or "use" as well as reference to different but related terms in case you want to expand your search.