Search engines compile databases consisting of hundreds of millions of web pages. They do this by sending out "spiders" to crawl across the web and map as many web pages as possible. Although search engines use different methods for compiling their databases, the basic idea is to index the contents of a site according to the words contained in it. However, spiders are programmed to work automatically and do not have reliable methods for determining which words are most important.
Examples:
Instead of compiling their own databases, meta-search engines search the databases of several search engines simultaneously. A meta-search engine can provide an overview of what's available on the web and can be helpful in determining which individual search engine will be most useful.
Examples:
InFind currently searches Webcrawler, Yahoo, Lycos, Alta Vista, Infoseek, and Excite. It merges results, eliminates duplication, and groups sites according to source type (e.g. Educational Institution Sites, Commercial Sites, Non-Profit Sites, European Sites, etc.).
Metacrawler may search Alta Vista, Excite, Google, GoTo.com, Infoseek, LookSmart, Lycos, Thunderstone, WebCrawler, and more. Results are ranked by relevance.
Subject Directories are lists of sites selected by human beings (not "spiders") using specific selection criteria and arranged according to subject. The distinction between Search Engines and Subject Directories is beginning to break down as more Search Engines utilize subject directories and more Subject Directories utilize Search Engines.
Examples:
Yahoo has a fairly comprehensive subject directory in the Humanities and is a good starting point for locating some of the most popular websites on your topic. Please Note: Although Yahoo has hired a staff of human beings to select and organize its listings, the quality of these sites is highly inconsistent and careful evaluation is always necessary.
Searcher Beware! As with most commercial resources, commercial search engines are searching out ways to get you to part with your money. Beware of commercial ploys. Don't, for example, "Click Here for Instant Access to the 101 Most Useful Websites" unless you are prepared to divulge personal information and spend some time and/or money. You can be reasonably certain that these 101 sites are not the most useful for your topic.
Library Gateways are compilations of quality sites on particular subjects that have been evaluated and selected by experts. Look for Library Gateways at the Community College of Philadelphia Library site and at other college and university library sites.
Example:
Yale University Library Selected Internet Resources in the Humanities is part of a larger project which also provides gateways in the Social Sciences, Business and Law, the Health Sciences and Science and Technology as well as the Humanities. Within the humanities gateway, other gateways are listed for major subject areas (e.g. "classics").
Specialized databases are listings of selected sites compiled by specialists in a particular field. Sometimes these specialists are simply interested individuals attempting to impose order on web chaos, but more often they are librarians or other professionals in academia, government or business. There is no single, centralized, direct way to locate specialized databases, but if they are of good quality, many other quality sites are soon linked to them and they become relatively easy to find. Note that the distinction between Specialized databases and Gateways is not always clear. For example, the Yale Library Gateway lists Voice of the Shuttle as a "gateway" for Classics.
Example:
Voice of the Shuttle Web Page for Humanities Research is a good example of a specialized database with links in a variety of humanities subject areas.
Search Query Basics
1. Phrases: Use phrases whenever possible. Phrases will often yield more focused
results than individual words.
2. Quotations Marks: Use quotation marks around a phrase so the search engine will
search for the phrase exactly as it appears within the quotation marks, and not the individual
words that compose it. 3. Keywords: Try to use at least three keywords; put the
most important words first; use nouns whenever possible.
4. Related Words: Use words related to your search topic that you might expect to
see in a web article on your topic.
Boolean Basics: Some Definitions
1. Query: the research question or topic you are sending to a search tool.
2. Boolean Logic: a mathematically based system of logic designed to streamline
search queries (a query is basically a question).
3. Boolean Operators: words like AND, NOT, and OR which are used to structure
research queries, making them more broad or more narrow. Full Boolean Operators are usually
used only with the advanced search options of most search engines.
4. Implied Boolean Operators: plus (+) and minus (-) signs used instead of Boolean
Operators AND and NOT. Implied Boolean operators are used with the basic search options for
most search engines. (+) includes; (-) excludes a keyword.
Simple Key Word Search: King Lear
1. Default: In most search engines, a simple key word search with no Boolean
Operators defaults to OR, meaning that your results will include all documents that contain
either King or Lear or both. Obviously, there is the potential for retrieving documents on
Lear jets as well as Shakespeare. 2. Phrase: The first step is to turn King Lear
into a phrase by putting it in quotation marks.
3. Go Boolean: Apply Boolean logic according to your purpose:
To Narrow Your Search: Use "AND" or plus (+) to retrieve only documents containing
all of your keywords. The more keywords you enter linked by the Boolean "AND", the more
narrow your search becomes.
Examples: * "King Lear" + symbolism (Implied Boolean--Basic)
* "King Lear" AND symbolism (Full Boolean--Advanced)
To Narrow Your Search: Use "NOT" or "AND NOT" or minus (-) to retrieve documents
containing your first keyword only when it appears without the second keyword.
Examples: * +"King Lear" -nature (Implied Boolean--Basic)
* "King Lear" AND NOT nature (Full Boolean--Advanced)
* +Romanticism -painting * Romanticism AND NOT painting
To Expand Your Search: Use "OR" to expand your search by retrieving documents in
which either one or both of your keywords appear. The Boolean OR is most often used for
keywords that are similar in meaning. Put parentheses around keywords linked by OR.
Examples:
* (College OR University) * (College OR Univeristy OR campus OR institution)
Purpose: Be as clear as possible about your purpose.
Ask yourself which of the following best describes your research goal:
* I am browsing in my subject area to see what's available
* I am trying to answer a specific question about my subject
* I am trying to retrieve all available information on my subject
Browsing: If you are simply browsing to see what's available, try the following
search tools: * Subject Directory: Start out by locating your topic within one of
the major commercial subject directories, such as Yahoo! or Magellan.
* Meta-Search Engines: Next, use a meta-search engine such as Inference Find
(www.infind.com) or Metacrawler to get a cross-section of what's available on several search
engines at once and a sense of which search engines might be most useful.
Answer Question: If you are attempting to answer a relatively specific research
question about a subject, try the following:
* Search Engine: After carefully structuring your research query, start with one
of the more comprehensive search engines such as Alta Vista
* Specialized Database: Next, try a searchable specialized database such as Voice
of the Shuttle (for humanities research).
* Retrieve all Available Information: If you are trying to retrieve all available
information on a given subject, try using the same query in several search engines.
Don't forget to consult good, old-fashioned print resources. For most subject areas,
these are still your best bet!
Tutorials:
Bare Bones 101: A Very Basic Web
Search Tutorial. University of South Carolina Library.
Finding
Information on the Internet: A Tutorial. Teaching Library Internet Workshops, University
of California, Berkeley. II. Search Strategies for the Humanities