Search engines are large databases of Web page files that manage information from the Internet. Results gathered from individual Web sites are returned to a user based on a query submitted. The results may be a list of full-text documents or a list of categories and subcategories to refine the search. A search engine provides an active link to Web sites containing the information the user is looking for. Results are most often ranked according to relevance.
Sample Search Engines
About.com is a directory similar to Yahoo that covers more than 50,000 subjects with over 1 million links to resources on the Internet. The directory consists of over 700 sites organized by individuals
called Guides, into 36 channels or subject areas. The Guides are experts in their individual subjects, who gather and create hundreds of thousands of pages of content to share with users. Guides are selected for their ability to provide the most interesting information for users, their commitment to finding the best sites, and their passion for their subject and the Internet.
Use broad or specific search terms, natural--language searching, + and – to include or exclude certain words, and quotation marks around phrases. Fewer and more specific words will make the searches more successful.
Alta Vista is a full text search engine, which uses “spiders” or “robots” to create its own databases from public Internet Web pages. It uses the word, acronym or phrase that is input and creates a database of Web sites containing those terms. The results are listed with the most relevant sites first. Alta Vista is considered a single or individual search engine since it searches individual sites only.
Additional features of Alta Vista include a directory of Web sites reviewed by its editors and organized by category. If you’re not sure what terms to search, you can select a category and follow its
path to get where you want to go. A section with Web tools allows you to send and receive email, map out a set of directions, translate foreign language information, catch up on the latest news, etc. A business center and shopping directory are also available from the home page.
Search techniques include natural--language searching, the default + and – phrase recognition, truncation using *, and nesting using ( ); Boolean searching (AND, OR, AND NOT, NEAR) is allowed in
advanced searching only.
Dogpile is a meta-search engine that transmits a search simultaneously to several individual search engines and their databases of Web pages. The default list of search engines queried varies. You can also customize Dogpile to search specific search engines. Results are retrieved in lists of 10 hits from each engine queried. If more than 10 results are found, a link to the next list of hits is given. It is important to remember that meta-search engines only spend a short time in each database and may only retrieve a small percentage of any of the results in any of the databases queried.
Dogpile References include a Favorite Fetches category with links to Autos, Health, Insurance Quotes, Travel, etc.; a Search Tools category with links to Maps, Weather, Stock Quotes, City Guides, etc., and a Web Directory with links to Auto, Home, Computing, Entertainment, Work & Money, etc.
Boolean operators and parentheses can be used; however, they will be removed when the search is sent
to a search engine that does not accept them.
Google is a search engine comprising more than one billion URLs and represents the most comprehensive collection of Web pages on the Internet. Google provides several benefits for the Web surfer. First, you see only the pages that include the terms typed. Unlike many other search engines, Google produces only results that match all search terms. Second, Google prioritizes results according to how closely individual search terms appear and favors results that have search terms near each other. Because of that, the result is much more likely to be relevant to a query. Third, Google allows users to search for Adobe Acrobat pdf files, by adding inurl:pdf to a search request. Finally, Google shows what the users get before they click on the link. Instead of Web page summaries that never change, Google shows an excerpt (or "snippet") of the text that matches the query—with the search terms in
boldface—right in the search results. That sneak preview gives a good idea whether a page is going to be relevant before it is visited.
This search engine uses AND as the default and OR to combine terms, and uses quotation marks for phrases.
The Yahoo! directory is a subject tree directory with online sites handpicked by the editors of Yahoo.
Results are arranged by relevance in subject categories and sub-categories first, then Web sites, individual sites, and finally Yahoo! News and Yahoo! Shopping. Fourteen broad categories are available on the home page if you are not sure where to begin.
The Yahoo! Network includes a shopping directory, news, live chat, and online tools and services. These features are available from the homepage.
Searching techniques use + and –, AND (default), OR; use quotes for phrases, and * to truncate.
Librarians’ Index to the Internet
The Librarians’ Index to the Internet is a searchable, annotated subject directory of more than
7,900 Internet resources selected and evaluated by librarians for their usefulness to users of public libraries. It’s meant to be used by both librarians and non-librarians as a reliable and efficient
guide to described and evaluated Internet resources.
A current awareness service is available in the form of a weekly email of the top 20 resources added to the index that week.
Searching techniques use AND (default), OR, NOT; use ( ) for nesting, * for truncation, and quotes for phrases.
WWW Virtual Library
The WWW Virtual Library, a subject-oriented catalog, consists of over 50 independently maintained subject indexes to Internet sources. It is a distributed, not-for-profit system of specialized directories and guides. The individual indexes maintained by experts in the field reside on hundreds of servers around the world. For example, NASA maintains the engineering index. Each WWW site’s
content is solely the responsibility of the maintainer. Subjects include agriculture, business and economics, computing, communications and media, education, engineering, humanities, information and
libraries, international affairs, law, recreation, regional studies, science, and society. The virtual library sites are collections of links to other sources, rather than primary data. Nevertheless, members
who contribute to the sites share the overall goal of providing access to the most valuable resources in their field.
Search parameters include Boolean searching, matching all or any words in the search field, short or
long display format, and sorting by date, title, or relevance score.
Search Engine Tutorials
The number of search engine tutorials on the Web is endless. Each tutorial is unique, but most cover basic search techniques, describe different types of search engines, offer comparisons of the features of many search engines, and give samples of the types of searches that can be done. Below are several examples of search engine tutorials taken from commercial, educational, military, and organizational Web sites.
Air University Library—Search the Net
Center for Army Lessons Learned—Virtual Research Library
(Click on the SEARCH button on left--hand side)
Dudley Knox Library, Naval Postgraduate School—Web Finding Tools:
Info People—Search Engine Quick Guides
Info People—Search Tools Chart
Librarians Index to the Internet—Search Tools
Ruth H. Hooker Research Library, Naval Research Laboratory—Search Tutorials &
University of South Carolina Beaufort Library—Bare Bones 101:
University of Southern California—Finding Information on the Internet: A Tutorial