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| Boolean Searching |
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Boolean logic is basic to searching. It is the process of narrowing or expanding a search by linking search terms with the connectors or operators:
AND
OR
NOT
and sometimes NEAR
It refers to the logical relationship among search terms and is named after British mathematician, George Boole.
Be sure to use capitals when typing your operators.
Operator |
Function /Action |
Example |
|
AND |
Both words must be present in the search results (not necessarily in the order they appear.) It narrows a search. Use it to combine two ideas which must be present |
London AND travel Violence AND classroom Child AND abuse Crime AND poverty |
|
OR |
Either word should be present. Use it combine synonyms or related terms. It broadens a search |
College OR university Adolescent OR teenager Sex OR gender |
|
NOT |
Narrows a search by excluding words or phrases. A word should not be present in the search results. Use it with caution since items can be easily eliminated. It is most useful when there are alternative meanings of a word. |
travel NOT luxury cats NOT musicals cancer NOT mice lotus NOT program |
|
NEAR |
Used to specify how close terms should appear to each other. |
Moon NEAR river |
|
" " |
Searches for a whole phrase in the order it appears. |
"LondonUnderground" |
|
+ or - |
"+" is sometimes used to mean AND. "-" is sometimes used to mean NOT. |
London + travel - luxury |
|
* |
Can be used as a wild card to return words that include all or part of the word. (Some sites do this automatically.) |
London AND travel* Returns London travel, traveler, traveling, etc. |
|
( ) nesting |
Allows the building of complex queries. By combining operators a search can be fashioned for a very specific topic. This is done by nesting, or placing certain terms in parentheses, or by creating number sets. |
(hogs or pigs) and market (sex or gender) and pay (cancer and fat) not mice |
Boolean Commands
|
Command |
How |
Supported By |
|
Or |
OR |
All but... |
|
None |
Google, Go, LookSmart, Yahoo |
|
|
And |
AND |
All but... |
|
None |
Google, Go, LookSmart, Yahoo |
|
|
Not |
NOT |
All but... |
|
AND NOT |
AltaVista, Excite, MSN Search, Netscape, Snap |
|
|
None |
Google, Go, LookSmart, Yahoo |
|
|
Nesting |
( ) |
All but... |
|
None |
Google, Go, LookSmart, Yahoo |
|
|
Near |
NEAR |
AOL Search (specify number) AltaVista & MSN Search (10 words), Lycos (25 words), WebCrawler (2 words) |
|
None |
Others |
The following Internet sites are helpful to learn more about Boolean searching:
Boolean Searching: http://searchenginewatch.com/2155991
Boolean Searching on the Internet http://www.internettutorials.net/boolean.html
HELP: Boolean Searching: http://media.lbcc.cc.ca.us/doc/BOOLEAN.HTX
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