Before you get started on your research, it's a great idea to brainstorm a list of keywords for all the key concepts in your research question.
Try some of these steps in thinking of keywords:
Sample topic: Does the death penalty unfairly target minorities?
Concept 1: death penalty
Alternative Terms: capital punishment, execution
Concept 2: unfairly targeting minorities
Alternative Terms: discrimination, racism, prejudice
Alternative Terms: African-American, Hispanic, ethnic groups
Keyword search allows you to use your own words to describe what you're looking for. This is how you typically search the Web using search engines like Google or Bing.
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 labeled Thesaurus or Subject Terms. Many databases allow you to search or browse their subject headings.
How do I find subject headings?