Directories or Subject Catalogs |
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Virtual Libraries |
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Specialized Databases |
- Specialized databases can be comprehensive collections of hyperlinks in a particular subject area or self-contained indexes that are searchable and available on the Web.
- ProFusion, at http://www.invisibleweb.com, accesses specialized databases and directories.
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Proprietary or Commercial Databases |
- Proprietary or commercial databases charge a subscription fee to use.
- Proprietary databases have certain value-added features that databases in the public domain do not have, for example, databases on FirstSearch, http://www.ref.oclc.org , have links to library holdings information. This way you can find out which libraries own the materials that are indexed.
- Proprietary databases also allow you to download information easily. For instance, Dow Jones Interactive, http://www.djinteractive.com , includes financial information that is commonly free to the public, but it charges for the use of its database because it has made it much easier for the user to download the information to a spreadsheet program.
- Proprietary databases often index material that others do not. The information is distinguished by its uniqueness, its historical value, or its competitive value. For example, Dialog, http://www.dialogweb.com includes difficult-to-find private company financial information and Infotrac's Searchbank http://library.iacnet.com and Lexis-Nexis Academic Universe, http://www.lexisnexis.com contain the full-text of hundreds of journal articles.
- Proprietary database systems are more responsible to their users. Because they cost money, they are more apt to provide training and other user support, such as distributing newsletters that update their services.
- There are also databases on the Web that are free to the public but charge if you want the full text of the articles indexed. The Electric Library, http://www.elibrary.com and Northern Light, http://www.northernlight.com , are examples of this type of database.
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| Search Engines |
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Meta-search Tools |
- Meta-search tools allow you to use several search engines; often simultaneously.
- They take your query, search several databases or search engines simultaneously, and then integrate the results.
- Examples of meta-search tools are MetaCrawler, http://www.metacrawler.com , and Ixquick, http://ixquick.com.
- An annotated list of meta-search tools is available at http://www.webliminal.com/search/appendix_a1.htm. See the Using the World Wide Web for Research, http://www.webliminal.com/search/search-web03.html , for more details.
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Library Catalogs on the Web |
- Libraries have often been at the forefront of making resources available through the Internet, and thousands of libraries allow Internet and Web access to their catalogs of holdings.
- Some resources for library catalogs accessible on the World Wide Web are LibDex, The Library Index, http://www.libdex.com/, and Libweb, http://sunsite.berkeley.edu/libweb.
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Email Discussion Groups |
- Email discussion groups are sometimes called interest groups, listserv, or mailing lists. Internet users join, contribute to, and read messages to the entire group through email. Several thousand different groups exist.
- Several services let you search for discussion groups. One is Catalyst, http://www.lsoft.com/catalist.html.
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Usenet Newsgroups |
- Usenet newsgroups are collections of group discussions, questions, answers, and other information shared through the Internet. The messages are called articles and are grouped into categories called newsgroups. The newsgroups number in the thousands, with tens of thousands of articles posted daily.
- Many search engines include the option of searching archives of Usenet articles, and some services-such as Google Groups, http://groups.google.com , keep large archives of Usenet articles.
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