When you put keywords and key phrases into the input box on a search engine, you are giving logical commands to an underlying database containing information about Web pages and other Web-based resources. These logical commands are often referred to as queries.
By understanding how basic queries work for most search engines, you will be able to use almost any search engine to find out if that search resource contains information about the kind Web sites that you seek. Keep in mind that the following information is generally true of search engines Check with the individual search engine to find out any relevant variations or exceptions.
Basic structure of a query
Queries may consist of individual keywords, key phrases made up of one or more words in quotation marks, and logical operators.
If an input box on a search engine or directory site were represented by brackets, an input box for a particular search would look like [keyword1, keyword2, "key phrase"].
There is no limit to the number of keywords and key phrases that you can use, but most searches of this type have around five keywords or key phrases.
Logical operators in a search
The three most important logical operators are OR, AND, and NOT. The operator AND is typically indicated by a “+” in front of a keyword or key phrase, and a NOT by a “-”.
Web pages containing keywords or key phrases with the AND operator are required to be in the results, and those pages containing keywords or key phrases with the NOT operator are excluded from the results.
The OR operator is the default value. If a combination of two or more keywords or key phrases have neither a “+” or a “-” operator, Web pages containing one or more of those keywords and key phrases will be included in the results.
Note that a search using a key phrase is more restrictive than a search using the AND operator with all the individual words from a key phrase.
Keyword and key phrase capitalization and using root words
In a search engine or directory query, the keywords are case sensitive. A lowercase keyword will return Web content with both the lowercase and capitalized version of the keyword. If the root of a word is used, Web content containing both the word root and variations of that root word may be returned. Unlike the case with keywords, a search usually returns only the Web content that has the exact spelling and capitalization of the words within the key phrase.
Making a query broader
Doing the following will broaden a particular query:
- Using fewer keywords or key phrases,
- Using lowercase instead of capitalized keywords,
- Using the root of a word rather than the entire word,
- Using the individual words from a key phrase instead of the entire phrase,
- Removing the AND operator from a key word or key phrase, or
- Removing the NOT operator from a key word or key phrase.
Making a query more narrow
Doing the following will narrow a particular query:
- Using more keywords or key phrases,
- Using capitalized instead of capitalized keywords,
- Using the entire word or a root word with a suffix rather than the root of a word,
- Using key phrases instead of keywords,
- Adding the AND operator to a key word or key phrase, or
- Adding the NOT operator to a key word or key phrase.
Common variations in queries
The following additional options are available on many search engines:
How to use a search engine
http://speedbrake.com/web/basicsch.htm — Revised: 10 October 2014