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ITE-115: Information Literacy Modules

2 b. Online search strategies

Keyword Search

A keyword search retrieves words or phrases from the important fields of the database records. In most databases a keyword search finds words in fields that have descriptive content, such as author, article title, source title (book, journal, magazine, or newspaper, subject/descriptor terms, and abstract. In some databases, additional fields may be included in the keyword search. And in other databases, a keyword search will search everything in every record.  Some keyword search engines allow you to specify which field(s) are to be searched.

A keyword search usually retrieves more items than a subject search, but they may not all be relevant. The computer is looking for the exact word you typed, not for the meaning or context of the word.

For example, a search on AIDS will retrieve items on...

  • aids for the hearing impaired
  • school aids
  • AIDS (the disease)

A keyword search is the best method to use when:

  • You are beginning your research
  • You are searching for a new trend or concept
  • You are not sure of the correct subject heading
  • The database does not have subject headings
  • You are looking for specific factual information

 Some search tips:

  • Use only significant words, not common words, such as the, of, an, and that.
  • Avoid using phrases such as "people with diabetes", or whole sentences, such as "How do people buy cigarettes if they are under 18?"

Subject Heading Search

A subject search involves searching the subject headings used in a database. Most databases include subject headings that are assigned to each record.

A list of subject headings, called a database thesaurus, ensures that all items about the same topic have uniform headings. Users can then retrieve all of the items on the same topic using one word or term, even when there may be several other ways to state the concept. By using the subject heading, you will retrieve every relevant item for your topic. Searching with a subject heading retrieves items ABOUT that particular topic, and it is a more precise search than a keyword search.

For example, you may want to research the topic death penalty.

Possible ways (synonyms) to state this topic include: 

  • Death Penalty
  • Electrocution
  • Capital Punishment
  • Hanging
  • Cruel and Unusual Punishment
  • Death Row
  • Lethal Injection

In the library catalog and Academic Search Complete database, the subject heading for death penalty is capital punishment, but the same term may not be used in other databases.

The thesaurus for the library catalog is called Library of Congress Subject Headings. If you would like to consult this resource, or if you are unsure whether a particular database has a thesaurus, ask a reference librarian.

Keyword vs. Subject Heading Search

Keyword Search:

  • May search multiple fields including subject, title, and abstract
  • May retrieve irrelevant items
  • Low precision, more results
  • Allows grouping terms to expand or narrow search


Subject Heading Search:

  • Searches for subject or descriptor field only
  • Controlled vocabulary from thesaurus
  • High degree of relevancy
  • High precision, fewer results
  • Requires knowing, finding subject headings

Search strategy tutorials

Using Boolean Operators

More Search Strategies

Alternate Boolean Operators


Type AND between your keywords to narrow your search. The database or search engine will only retrieve those articles or web pages that contain both words. Using AND will decrease the number or hits or articles or web pages in your result list.

Example: school AND crime

Note: Some databases and search engines (such as Google and Craigslist) allow you to type a plus sign (+) in front of a keyword when doing a basic search. This works the same as AND.

Example: +school +crime


OR     undefined

OR Type OR between your keywords to broaden your search. The database or search engine will retrieve those articles or web pages that contain at least one of these words. Using OR will increase the number of articles or web pages in your result list (especially if not used in combination with AND or NOT). Use OR between keywords that are synonyms or have similar meanings.

Example: baby OR infant


NOT     undefined

Type NOT before a keyword to exclude that keyword from your search. Using NOT will decrease the number of articles or web pages in your result list. The best use of NOT is when you are searching for a keyword that may have multiple meanings.

Example: bat NOT baseball

Combo     undefined

Use parentheses ( ) to keep combination searches in order. In the example below, the database or search engine will retrieve articles or web pages that must contain the word law and at least one of the words in parentheses.

Example: (ecstasy OR mdma) AND law

Web Tutorials

Other schools have put together demos and tutorials on various search techniques.