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2. Keyword based: Keyword based search engine helps to search information when related words for
required information are typed. The engine displays a list of web pages that contain information
related to the typed words. It is more useful for searching about topics that do not occur under
general subjects or categories.
When a user submits a few words related to the information to the search engine, it starts searching
for that information to match the web pages related to the user’s information and then displays the
list of the locations that match the search criteria. These types of search engines are also called index
based search engine. For example: www.google.com, www.bing.com, www.altavista.com, etc.
How does a Search Engine Work?
A Search Engine works in the following ways:
A search engine must have a very strong database for which the search engines use powerful programs
called ‘Spider’ or ‘Web Crawler’ that keep on crawling on the web to catch any newly published web
page or document and find their web address.
The documents and their web addresses are sent to the indexing tool which stores it in a database. It
also prepares an Index so that the information can be retrieved quickly from the database.
When the user enters the keywords or a query, the search engine weeds through millions of web pages
and the search software searches its database with the help of an index and displays the matching
documents or links.
Search engines display the related information in a hierarchical order, instead of being listed by how
relevant the search engine thinks the site to search. On the other hand, guides or indexes contain links
to many important resources on a topic. They search the contents of websites. The indexes usually
rank the search results in order of relevance in accordance with how closely the document matches the
content that is searched for.
Do you know?
Presently, there are more than 1.7 billion web pages on the Internet and this number is increasing day
by day. Incidentally, even the most powerful search engines cover only a small percentage of the web!
Suggested Tips for Using a Search Engine
To make an effective search on the Internet for a specified information:
Be specific, use synonyms and use lower case letters.
Avoid using common words, like ‘Internet’, ‘Computer’, etc., as these words are too general, hence the
search engine will display thousands of matching web pages.
Many search engines can search for information with a combination of multiple words. By using the
Boolean Operators (AND/OR/NOT) in queries, the result of searching can be better.
To search information on the basis of words or a phrase or a title, enclose them within quotes. For
example, to find a book named ‘The ABC of the Internet’, type “The ABC of the Internet” in the search
box of the search engine.
Use wild cards like asterisk (*) to search for related words without entering the full word. For example,
if we type ‘*comput*’, then the search will include computer, computers, computing and other related
words starting with the letter ‘comput’.
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