Searching the Web and licensed Databases
“On the Web” vs. “Via the Web” searching
On the Web Searching
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•
•
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Subject Directories
Specialized Directories
Web Databases
Search Engines
Information retrieved from these
sources …
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•
•
May or may not be from
reliable sources
May or may not have
standard bibliographic
information—author, title,
publisher, date.
Mostly free
Examples: Yahoo! Google
Via the Web Searching
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•
Licensed or proprietary
databases
Usually requires user
subscription or pay per
search
Information retrieved from these
sources…
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•
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Usually not available
through a search engine, a
subject directory
Will usually have standard
bibliographic information—
author, title, publisher, date
Usually high quality,
refereed, reliable (i.e.,
instructor approved)
Examples: InfoTrac OneFile, SIRS
*Chart adapted from The Invisible Web, by Chris Sherman and Gary Price
Web Search Tools – On the Web Searching
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Subject Directories
o Compiled by people (intuitive)
o Groups “like subjects” together (Wall Mart shopping) under
Subject Headings
o Subject Headings not standardized and will often vary
among directories. Compare with library catalog subject
headings, which are more elaborate and standardized.
o Hierarchal structure (broad to narrow)
o Not a full-text index of Web pages in the categories;
usually indexes titles, descriptions, etc. Compare with
search engines.
o Evaluation of Web sites varies with individual directory
o Useful if
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Need an overview of the topic (subject search)
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Need evaluated resources
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Need specialized databases or Deep Web sources
Example Subject Directories & Specialized Directories
(Virtual
Libraries/Vortals)
o
o
o
o
o
o
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Yahoo! > http://dir.yahoo.com
About.com > www.about.com
Infomine > http://infomine.ucr.edu/
Librarians’ Index > http://lii.org
FindLaw > http://www.findlaw.com
FirstGov > http://firstgov.gov
Example of Web Databases
o Medline > http://gateway.nlm.nih.gov/gw/Cmd
o Internet Movie Database > http://www.imdb.com/
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Search Engines
(On the Web Searching)
o Computer programs that harvest information
o Contents not selected by humans (not so intuitive)
o Results not organized into Subject Categories (although
selected results may link to Subject Categories)
o Results ranked by algorithm (varies with SE); i.e.,
automated evaluation.
o Usually indexes entire Web page
o Unevaluated results**
o Doesn’t find everything (static pages only).
o Usually requires knowledge of search techniques (Boolean,
Proximity, Phrase, Field, etc.) to be most effective.
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How Search Engines Work
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Boolean Queries
o And
o Or
o Not
•
Proximity Searching
o “word order important”
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Field
o
o
o
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Non-Boolean (non yes/no)
o Natural language queries
o Results may be “weighed” based on word
order, word placement, rarity, etc. (See
InfoTrac OneFile’s Relevance search for
example.)
Searching
Title
Text
URL
**For fun, can you tell which of the following Web sites is legitimate.
1) http://www.gatt.org/
2) http://www.wto.org/
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Typical Search Engines
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Google
http://www.google.com
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Teoma
http://www.teoma.com
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AlltheWeb
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AltaVista Advanced http://www.altavista.com/web/adv
http://www.alltheweb.com/
Why select a Search Engine
o Looking for esoteric, hard-to-find information
o Looking for most current information available
o Looking for a variety of viewpoints (alternative views of
social issues, etc.)
Via the Web Searching
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Proprietary Databases
o Requires payment or subscription
o Use the Web and a browser to search these
databases, but information is not available to Search
Engine spiders (pages are dynamically generated;
Search Engines gather information from static Web
pages).
o “Safer” to use in academic research. Information will
be more reliable, is often peer-reviewed, and will
have standard bibliographic information (title,
author, date, publication information).
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Example databases (currently available at PHCC)
o InfoTracOne File
o SIRS Knowledge Source
o Factiva
o Literature Resource Center
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Off-campus Access to Databases
o Instructions available on Library Homepage
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Citation Information
o APA
o MLA
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Note Web vs. print citations
Information Literacy Tutorial
o Available on Library Homepage
6/06