Google vs. Boolean Search Operators
Being a former librarian, I decided to
write a post about Boolean searching. However as I researched the
topic, I realized that exact Boolean searching is not used in most
online search engines. Therefore, I have summarized both Google Search
Operators and Boolean Search Operators below. Boolean Search Operators
will be used to search subscription databases at many libraries.
Google has advanced search
tools for text and for images that can be filled in to give great
results. These can be found as follows:
http://www.google.com/advanced_search
http://www.google.com/advanced_image_search
If students are going to use a custom Google search engine such as Infotopia.info or Kidtopia.info
why not use Google's advanced search tools? There are many
simple search operators that can be used in a Google Search that will
give excellent results as well.
Search Operators for Google Search
1) To search for an exact word or phrase
Use quotation marks to search for an exact word or a set of words. This
works well if you are looking for a line from a book or poem, song
lyrics, and if you are looking for an exact word or phrase. You no
longer have to use AND to put two words together in your search.
Examples:
"Call me Ishmael"
"if I had a hammer"
"Abraham Lincoln"
2) To Exclude a Word
To exclude a word, use a minus or dash sign before the keyword in your
search, such as if are looking for a cougar and you don’t want to
include a car brand. If you want to exclude a web site in the results,
just type the keyword and follow it with the minus sign as follows:
Examples:
cougar -car
cheetah speed -car
climate -site:wikipedia.org
3) To Search Within a Site
If you want to search within a site or domain, just type the keyword
followed by a space and the site name or the ending of the site, as
follows:
Examples:
climate site:abc.com
climate site:.gov
4) To Search for Linked Pages
If you want to search for pages that link to a URL, just type in link: and the name of the URL.
Example:
link:cnn.com
link:google.com
5) To Search for Related URLs
To search for pages that are similar to a URL, just type in related: and the name of a URL that you want to compare.
Example:
related:cnn.com
6) To Use a Wildcard
If you want to fill in the blank for a quotation or a phrase you are
looking for, use an asterisk (*). Be sure to enclose the phrase in
quotation marks. This is sometimes called a “wildcard.”
Example:
“Roses are * Violets are *”
7) To Use OR
To search for either word in a keyword search, use OR in all capital letters.
Example:
teenager OR adolescent
Boolean Searching is a useful way of entering search terms into a
database to improve the quality of the results. It is based on a method
of logic developed by George Boole, a 19th century English
mathematician. Because most databases support Boolean searches, it
allows you to more effectively select your search terms and thereby
limit your results to obtain quality information.
Boolean operators include the following:
AND
“AND” helps you to specify what you are searching for. If you were
searching for the word “cougar” and you only wanted results that
includes animals, not the “new” connotation for the word, you could type
the following into a search box.
cougar AND animal
NOT
“NOT” helps you to limit your search. If you were searching for a
“jaguar”, you might want to exclude automobiles from your search to
limit the results.
jaguar NOT automobile
OR
“OR” helps you utilize several terms for the same keyword search. If
you are searching for articles on teenagers, you might specify
“teenagers” OR “adolescents” to improve your search results.
teenagers OR adolescents
ADJACENT
If the search terms that you are looking for are usually adjacent to
each other, try putting all the terms in quotation marks. If you
entered the words Abraham Lincoln in a search box, you would get a number
of Abrahams and Lincolns, though not exclusively Abraham Lincoln. Here
is how to enter the adjacent search words:
“Abraham Lincoln”
NESTING
If you want to group search terms for more complex searches, use parentheses, as follows:
fruit AND (orange OR grapefruit)
(teenagers OR adolescents) AND facebook
Resources for Boolean Searching
Colorado State University has a tutorial on using AND, OR, and NOT in Boolean Searching.
http://lib.colostate.edu/tutorials/boolean.html
A project of the Board of Regents of the University System of Georgia
http://www.usg.edu/galileo/skills/unit04/primer04_08.phtml
Boolean Searching Information from Penn State University
http://www.gv.psu.edu/foweb/lib/boolean_search/start.html
Library of Congress Online Catalog Help Page
http://catalog2.loc.gov/help/boolean.htm
