WWW Search Engines
Where do I find the URL's (internet address) of the search engines?The
Library of Congress site has links to popular search engines:
LC's search engine site
What is a search engine?
- From a searchers' perspective:
On the internet, search engines are in the form of a web page which
contains a form into which a user types a text string query, clicks a button,
waits a bit, and the engine retrieves a list of Web sites that matches the
- From a technical perspective:
Search engines are databases of WWW pages and search engines provide search
capabilities. Search engines have two components: collection of web pages
organized in a database and a search interface so searchers can enter queries.
Why does each search engine give different results for the same
query?Search engines are not alike. They have different
characteristics such as:
- The database content of the search engine: WWW pages, Usenet news,
and classified ads.
- Indexing method
- How many sites do the search engines claim to index?
- What method of indexing is used? Full-text
Parts of the document such
as the URL, title, headers, the most frequently used words or part of the
- Search features (these tend to vary among the search engines)
boolean searching (the use of AND, OR,
search limiting features: by date, geographic location,
ease of use - a good search interface, display of online
documentation such as: HELP, Search Tips, FAQ's, and Advanced Searching
display of results - are site summaries included? Are the
results ranked? How does the search engine determine
truncation - retrieving several terms by entering only a word
followed by a symbol such as * or ?.
case sensitivity - Does the search
engine establish retrieval based on the exact upper and lower case
weighted search - allows user to control the relevance of search
results by preceding works with + or - to increase or decrease the
importance of words.
How can I search effectively or gain comprehensive results? Search
more than one database!
Keep in mind good searching techniques:
- Create an appropriate query; ie, identify the concept and select
- Know the correct syntax for each search engine.
- Does the search engine
- Know how to search by phrases.
- Does athe
search engine support right and middle truncation?
- Watch your spelling!
- Refine your search through the use of:
Boolean Operators: AND, OR, and NOT
Proximity Operators - specifying
how words should be positioned. For example should the words be side-by-side
or within 5 or 10 words of each other. (Usually quotes or NEAR are
Limit the search by field:
- link to: (how many documents link to; eg, infoseek.com)
- site: sun.com
- url: (a word appears in the URL)
- title: title of the document
- Read the on-line instructions for searching under the following possible
headings: Help pages, FAQ's, Searching tips and Advanced Searching.
Keep in mind the following conclusions:Search engines are
evolving - the search interface and search features may change.
Search engines are trying to keep upwith the volume of information on
A continued challenge of search engines is:
- How to find everything on a specific subject on the WWW as the universe of
networked computers expand and the number of web pages expand.
- How to index the data and connect the searcher with the single piece of
information that is needed.