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Library Basics: Keyword/Boolean Searching (K/B): an Introduction

Learn the basics of searching the library, what the Library of Congress Classifications are and where to find them in our library

Keyword/Boolean Searching (K/B)

Keyword/Boolean Searching

An Introduction

Keyword searching allows you to search for the appearance of any term, anywhere in an individual item record in the ISU Library Catalog.  Internet search engines and many online databases such as journal indexes also use K/B searching to help you tailor your search.  By using Boolean operators (discussed below) you may search for more than one term at a time, specify logical relationships between terms, and define their proximity to one another.  The limits of traditional searching are removed (e.g., only being able to search by a specific subject heading; needing to know the first word of a title).  This handout describes K/B searching in the ISU Library Catalog, the online catalog, but the concepts are the same for most electronic systems.  The ISU Library Catalog offers both Keyword and Boolean/Keyword options. Different search techniques are used for each search option.  

 To search by keyword, select Boolean Keyword Searching.   For example, in keyword/Boolean searching, you could search for any word appearing in a title.  You could find The Witches of Eastwick by entering:  eastwick  or  witches.  


Stopwords:  These are "short" words (all, at, some, this, etc.) which cannot be used as keyword search terms.  Many databases have stopwords. Use of stopwords in a keyword search yields no search results. the ISU Library Catalog has no stopwords.  

Punctuation:  Keyword  searches are usually punctuation sensitive; omit apostrophes, parentheses, hyphens, etc.  For example, type  dont  instead of  don't,  CD ROM  instead of  CD-ROM. 

Boolean Operators

Logical Operators

Logical Operators

Boolean logical operators allow you to retrieve records that contain your search terms.  The primary Boolean logical operators are:  

AND      Each record must contain all search terms

(AND tends to narrow a search); and  

OR        Each record must contain at least one search term

(OR tends to broaden a search)           

Boolean Operators
Examples of Logical Operators
baseball AND olympics <ENTER>        Each record will contain both terms  
sports OR athletics   <ENTER>            Each record will contain one or both terms 



Use of the truncation symbol  * is the most efficient way to look for variant spellings of words, singular and plural, etc.  You can use truncation with any other combination of Boolean operators, or by itself.  Enter the truncation symbol at the end of whatever stem word you wish to search.  Some databases and search engines use the asterisk (?) or the exclamation mark (!) for their truncation symbol.

  • Use truncation to avoid having to think of and type out all possible variations of a word
    • e.g. plan* will retrieve plans, plants, planes, and planner
  • Use with caution to ensure relevant words are being retrieved; in some cases, you should avoid truncating a keyword too far to the left
    • e.g. can* will retrieve cans, candy, cancer, candles, etc.
  • Truncation symbols can vary among databases:
    • EBSCO Databases (e.g. CINAHL, SPORTDiscus, America: History and Life with Full Text) truncation symbol is an asterisk (*)
    • PubMed truncation symbol is an asterisk (*)
    • Web of Science truncation symbol is an asterisk (*)
    • Check the help screen of other databases to find out which symbols are used

Some databases allow for embedded truncation; e.g., wom*n would retrieve records containing the words woman or women.

Examples of Truncation:  
colo*        <ENTER>   Retrieves color, colours, Colorado, colony, etc.  
colo*2      <ENTER>   Retrieves color, colors, colour, colon, etc.          

Positional Operators

Positional Operators

Boolean positional operators allow you to retrieve only those records in which your search terms appear in a specific order in relation to each other.  The primary Boolean positional operators are: 

Adj       Search terms must be adjacent (side by side), in the same order;  

Same   Search terms must be in the same bibliographic record field,
               but may be in any order.  

Near     Search terms must be next to each other but may be in any order.  

Some databases allow you to specify that words must be in the same sentence, same paragraph, within x/words of each other, etc.  In the ISU Library Catalog Keyword searching, 'as a phrase' equals adjacent.  In the ISU Library Catalog' Keyword/Boolean search mode, enter phrases in quotes (e.g., "world wide web").  Also, in the ISU Library Catalog's Keyword/Boolean search mode, you must enter the boolean operators in ALL CAPS (e.g., "WORLD-WIDE WEB" OR INTERNET).  



As in basic algebra, by using parentheses you may specify the order in which operations take place (those inside parentheses are performed first).  More complicated strategies then become possible.  

Examples:    (athletes OR sports) AND drugs  (airport? OR airplane?) AND terror?  

The first example will retrieve records in which the words athletes AND drugs OR sports AND drugs appear.  The second is a broader search and will retrieve airport, airports, airplane, airplanes in records where the term(s) terror, terrorist, terrorize, terrorists, or terrorism appear in the same record.  

Remember, when you are searching in different indexes, catalogs, or search engines, it is important to read the Help screens in order to search successfully in that particular database.     If you need help with keyword searching or other library resources, ask for assistance at the Information Desk (1st floor) or call 237-2580.

Default Operator

Default Operator

When you type in a keyword search without specifying a logical or positional operator, the default operator of AND is automatically assumed by the ISU Library Catalog.    

ProQuest Advance Search

ProQuest's Advanced Search Mode
offers these options:  

  • Pre/N [precede by]: Use PRE/N BY to find articles that contain the first specified word or phrase preceding a second by a specified number of words. For example: world PRE/3 web
  • W/N [within]:  Use WITHIN to find articles that contain a specified word or phrase within a specified number of words of another word or phrase.   For example: computer W/3 careers
  • W/DOC [within document]:  Use W/DOC to find articles that contain one or more specified words or phrases. For example: internet W/DOC education 


Library Instruction, Indiana State University Libraries, Terre Haute, IN – 10/99 from Marsha Miller's handouts/keyword2page