What is the difference between a keyword and a subject?

Answer

A keyword search uses everyday words and phrases to describe your topic. You'll usually get several results this way, but they may not all be relevant. This is because your search terms can appear anywhere in the record, such as the title, author, subject or summary.

Subject headings describe a topic. Searching by subject heading will often bring back fewer results but they will often be more accurate. To search by subject, you have to know the specific word or phrase used to describe your topic. The controlled vocabulary used will vary from database to database. So, subject terms used in CINAHL will not necessarily be the same as subject terms used in MEDLINE. Each database will have its own thesaurus or list of subject terms that you are able to search.