Search Engines

What is a Search Engine?  Software programs that search the Internet for a topic, catalogs the results, and displays the sites found.  Also called Spiders or Web crawlers  Save time in researching by displaying descriptions to be read before visiting sites found.

Types of Engines  Subject-and-Keyword – build their own catalogs by gathering and organizing it from other sites prior to being asked for a specific search string.

Types of Engines  Multi-threaded engines – are slower search engines because they don’t maintain their own catalog. They search specific strings only when asked.

Catalogs  Hierarchical – Goes faster because a person is able to narrow their search by categories prior to asking a search engine to find a specific search string.  Subject – looks for the word but may bring up other topics

Text String  Words or phrases used to narrow a search area

Searches  Simple Search – uses only one or two keywords (broadest kind)  Complex Search – uses Boolean operators (AND, OR, NOT, etc.) and grouping operators (double quotes, parentheses) (contains several words and also operators to modify the text string)

Error Messages  Site may be busy or temporarily down  Either server or site may no longer exist  Server unavailable at this time  Server not found  Unable to find a file

What to Do  Check for typographical mistakes  Check for proper capitalization of proper nouns  Check the spelling of keywords  Try spelling variations of keywords  Try a different search site