Internet Search Techniques

When you use an Internet search engine, the use of Boolean logic may be used in three different ways: Full Boolean logic, Implied Boolean logic and Predetermined Language.

1.   Full Boolean logic can be used with many search engines. These "operators" use primarily the three words: or, and, not.

Query: I need information about cars. This search would include results that include either terms:   cars or autos

Query: I'm interested in sports medicine. This search would include results that include both terms:   sports and medicine

Query: I'm interested in planes but not jets. This search would include results that would include one term but exclude the other term: planes not jets.

2. Implied Boolean logic refers to a search in which Boolean operators are not used. Symbols are used to represent Boolean logical operators. Implied Boolean logic has become considered almost standard.    

Query: I need information about cars. If you wish to find the result that include all terms in your search, type:   cars[space]autos. This example holds true for the search engines that interpret the space between keywords as the Boolean and. Nowadays, most engines use the and logic as the default for the [space] key.

Query: I'm interested in sports medicine. Another way to use the Boolean and is to use the [+] key:   +sports +medicine. You can also use quotes around the phrase, "sports medicine" to get results using the exact phrase.

Query: I'm interested in planes, but not jets. To exclude a term from your search use the [-] key:   planes -jets

Query: I want to learn about plane engines but not jets. You can use a combination of symbols:   plane -jets +engines.

3. Predetermined Language is used as a fill-in template. Sometimes search engines offer a search template which allows the user to choose the Boolean operator from a menu. Often the "logical operator" is expressed with substitute language. Examples of substitute language might be as follows: can include, must not include, must include.

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