Skip to Questions

Ask a Librarian

Useful Tip: If nothing matches, start typing your question above and continue in the yellow email form on the next page.

Do you have any tips on searching? I'm not getting what I want, and I'd like to make my search more precise?

How do Boolean operators work?
Last Updated: Feb 22, 2013  |  45 Views

Was this helpful? 0   0


Boolean Operators

Boolean operators (AND, OR, and NOT) allow you to make catalog or database searches more precise and effective. Use AND or OR to specify multiple words in any field, any order. Use AND NOT to exclude words. The Advanced Search from of the catalog and most databases allows you to select the boolean operator you wish to use from the drop down menu next to the search box.

Examples from the Library Catalog:

stocks and bonds
stocks or bonds
stocks and not bonds


Multiple Words

When searching multiple words, the system will automatically supply the Boolean AND operator between each word; each of the words entered for the search will occur somewhere in the retrieved records though not necessarily in the order entered.

Examples from the Library Catalog:

(Both of these searches will retrieve the same results.)

university science department
university and science and department


Phrase Searches

Search for complete phrases by enclosing the phrase in quotation marks. Words will appear together in all results exactly as typed.

Example from Library Catalog:

"modern medicine"



We refer to the asterisk (*) as a wildcard. It matches any number of characters. Searching for "therap*" will find "therapeutic", "therapies", "therapist", "therapy", etc. You must type at least two charactes before the asterisk.

The queston mark (?) is another type of wildcard. You may use '?' to replace a single character anywhere within a word.

Examples from the Library Catalog:

* Wildcard:
environment* polic*

? Wildcard:


Proximity Operators

The NEAR operator is used to retrieve records that contain the specified words or phrases within ten words of each other in the same indexed field. The WITHIN operator is similar to the NEAR operator, but allows the user to specify the maximum number of words that may appear between the specified words. WITHIN 10 and NEAR are equivalent.

Examples from the Library Catalog:

international near conference
fractal within 3 geometry


Field Limits

Field limits may be specified by selecting a field limit from the selection list. These limits appear before the word or phrase to be searched. A field limit causes the system to search only the specified field for the specified word(s).

Field Limits and their meanings:

  • Author: Search only author fields
  • Title: Search only title fields
  • Subject: Search only subject fields
  • Note: Search only note fields
  • Subject: Search only subject fields



Keyword search results are usually grouped by relevance to bring the most likely titles to the top of the list. Each group represents a similar level of relevance and results are sorted within the group by date or title. To get an ungrouped result set, use boolean operators to form a complex query.

Most relevant Most relevant titles 

Highly relevant Highly relevant titles 

Very relevant Very relevant titles 

Relevant Relevant titles 

Other relevant Other relevant titles

Answered by UHD LibrarianBookmark and Share

Other Answers / Comments (0)

    More Ways to Ask a Librarian

    Frequently Asked Questions

    Email Us!
    Live Chat
    (24/7 - Including Holidays)
    (713) 221-8187
    (713) 489-4771
    In Person - 4th Floor North
    Schedule an Appointment

    Browse by Popular Topics

    Alumni Privileges  –  APA  –  Art  –  Biology  –  Business  –  Business Cornerstone (company, industry,country research)  –  Career  –  Catalog FAQ  –  Checkout/Checkin  –  Chemistry  –  Citation Format  –  Communication  –  Computer Information Systems  –  Copyright  –  Criminal Justice  –  Databases  –  Distance Education  –  E-Books  –  Economics  –  Education  –  Employment  –  English  –  Environmental Science  –  Faculty FAQ  –  Films on Demand  –  Finance  –  Financial Aid  –  Gender Studies  –  Health Sciences  –  Higher Education  –  History  –  Interlibrary Loan  –  International Business  –  IT Questions  –  Journals  –  Law  –  Library Information FAQ  –  MBA  –  MLA  –  Newspapers  –  Political Science  –  Psychology  –  Remote Access  –  Research FAQ  –  Sociology  –  Statistics  –  Sustainability  –  UHD Information  –  Video  –  Writing  
    View All Topics