Search Tips

Boolean AND, OR and NOT | Truncation and Wildcards | Phrase Searching

Putting Concepts Together - Boolean AND, OR and NOT

Web search engines like Google assume you want to search all terms you type in. Other web search engines rank by relevance - results with all terms come up first, then results with only one term. Library databases have more sophisticated search capabilities and requirements; you must specify how the system should deal with multiple terms.

Use the operators AND, OR or NOT to combine keywords or phrases.

• AND narrows a search - results must contain both terms.
  Use AND to combine separate concepts.
• OR broadens a search - results can contain either term, or both.
  Use OR to combine synonyms.
• NOT narrows a search - results can contain one term, not the other.
  Use NOT to exclude terms

Operator	Sample Search	The search will find...	Diagram of Results
AND	careers and medicine	Items that contain both "careers" and "medicine"
OR	occupations or careers	Items that contain either "occupations" or "careers"
NOT (sometimes AND NOT)	assisted suicide not kevorkian	Items that contain "assisted suicide" but not "kevorkian"

Truncation and Wildcards

A symbol at the end of a word stem provides for all variants on the word stem. The most commonly used symbol is the asterisk (*), but this varies among databases.

For example, a search for

librar*

will retrieve:

library, libraries, librarian, etc.

Be careful not to truncate too far, or you will retrieve unrelated words!

Internal Truncation

A symbol within a word provides for all possible variants inside a word or word stem. The most commonly used symbol for internal truncation is #. For example, a search for

wom#n

will retrieve:

woman, women

Look at online help for each database to determine the truncation symbols.

Phrase Searching

Some databases require a phrase to be in quotes.  Ex: "higher education"

Content based on Duke University Guide to Library Research: Electronic Searching