Online Sources – Specialty Search Engines

INVISIBLE WEB (click for introduction)

There's a big problem with most search engines, and it's one most people aren't even aware of. The problem is that vast expanses of the Web are completely invisible to search engines. Even worse, this "Invisible Web" is in all likelihood growing significantly faster than the visible Web.
The Invisible Web is made up of information stored in databases. Unlike pages on the visible Web, information in databases is generally inaccessible to the software spiders and crawlers that compile search engine indexes.
Search engine spiders are the map makers of the Web. They record the addresses of Web pages they discover. When they come across a database, though, it's as if they've run smack into the entrance of a massive library with securely bolted doors. Spiders can record the library's address, but can tell you nothing about the books, magazines or other documents it contains.
Fortunately, there are guides to the thousands of databases that make up the Invisible Web.
Freeality Internet Search Different Internet search tools.
DocDel Search for services that retrieve publically available documents, including patents, military specs, government reports, journal articles, etc.
Digital Librarian Margaret Vail Anderson maintains this librarian's choice of the best of the Web, with thousands of links in dozens of categories.
CompletePlanet The claims for this engine of engines are heady indeed: "the source of all search," with an index of 200,000 deep web engines and databases plus 45,000 search sites on the "surface." This is a good starting point for accessing the rich resources of the "hidden" Web.
Infomine Infomine might be called an "academic" search engine, focusing on scholarly resource collections, electronic journals and books, online library card catalogs, and directories of researchers

From Intelliseek, the makers of the BullsEye meta search software, catalogs searchable resources across the web. Also used for the Lycos Invisible Web service, below.

LexiBot Software tool designed to let you bring back information from "invisible" or "deep" web resources.
Lycos Invisible Web Catalog Produced in partnership with Intelliseek, this search engine gives you access to all sorts of online databases.
Direct Search Like the Lycos Invisible Web Catalog, Direct Search takes you to all types of helpful specialty databases that may have the information you are looking for.
WebData Comprehensive guide to searchable databases. Browse or search through listings. WebData is a database portal, specializing in finding, categorizing and organizing online databases, and providing annotated links with quality rankings
WebGator Investigative Resources on the Web
YBlost The Directory of Directories
Excite Precision Search Excite accesses a medium-sized search database and applies post-processing based on popularity to come up with a more focused, relevant result set. Offers "Zoom In" function to help with your search terms.
Ask Jeeves Ask Jeeves is a human-powered search service that aims to direct you to the exact page that answers your question. Pick a category, then choose a volunteer, then ask your question.
Information Please Information Please almanacs are favorites among researchers who need trustworthy facts. This site allows searching across Information Please's various almanacs, its encyclopedia and its dictionary.
KnowPost Ask a question, get an answer -- but you have to also answer questions yourself.
Experts Exchange Free "ask an expert" site.
Infostry NB --- to check the link A place where people can provide knowledge, ask questions, and get rewarded for it. Enter a question, and within a few minutes, a human being will respond with an answer via this web site.
FirstGov Provides searchable access to information from the US government plus US state and local governments. Information can also be browsed by category.
Google US Government Search Special edition of the Google search engine that limits results to pages from US government web sites. .Search engine that crawls US government and state government web sites.
usgovsearch Searches across US government web sites and information from the NTIS (National Technical Information Service).
Government Information on the Internet Not a search engine but a well-respected book about finding government information online.
Forum One Allows you to search over 300,000 web-based discussion forums. is a meta search engine operated by Cnet. It offers both web-wide search and a wide variety of specialty search options. uses technology from SavvySearch, which was acquired by Cnet in October 1999. The SavvySearch site itself no longer operates. SavvySearch was one of the older metasearch services, around since May 1995 and formerly based at Colorado State University.
AmeriStat Looking for US population data? This new research portal provides data about children, fertility, marriage and much more.
Informagen Informagen is an Internet-based Applications Service Provider (ASP) providing bioinfomatics tools, biotechnology databases and consulting services to the genomics, proteomics and biopharmaceutical industries. We provide the cutting edge strategic intelligence needed to exploit information and to develop future business strategies.
Ask Magpie
Directory that lists magazines from all over the world. It also takes you to the magazine web site, if available.
CI Resource Index
Lists sites for finding competitive intelligence (CI) resources on the Web.
b2bexcite A search directory geared exclusively to business to business (B2B) web sites.
Domain Notes A great resource for all things domain. Helpful links, news and a wizard to find domain names.
Amnesi Can't remember the exact URL of a web site? Tell Amnesi what you remember, and it will provide of list of sites it thinks match. The Java interface is a bit clunky and slow, but the results are impressive.
Enter keywords, select the domain search option, this service will locate active sites with domain names that contain those keywords.
Long a favorite for those looking for mailing lists.
E-Zine List
Long running list of mailing lists maintained by John Labovitz. Unfortunately, it is not searchable.
List of Lists
Search or browse for lists of interest.
Publicly Accessible Mailing Lists (PAML) A long-time and well-known place to find mailing lists.
eGroups eGroups allows you to search for mailing lists of interest, or to read actual messages and post via an online interface. You can also start your own mailing list for free.
Internet Scout New List
Not a search engine for mailing lists but a mailing list about new lists or changes to existing lists. The archives are searchable.
WEB RINGS Web rings are groups of sites that have linked together around a similar topic. For example, sites devoted to Xena: Princess Warrior might form a ring. Each would install special code on their pages, making it easy to click to the next site in the ring. The services below help sites form rings. For the searcher, you can browse or search the various rings offered as an alternative way of discovering sites of interest.
Newsgroup search engines are also is a great way for journalists to track down potential sources. For web developers and marketers, searching newsgroups can show you exactly which ones are relevant to your needs. And for general users, newsgroup search engines can help point you to those talking about similar interests online.

Formerly Deja News, the site underwent a major facelift in May 1999 and added new features. However, usenet / newsgroup searching still remains available.

Forum One
Allows you to search over 300,000 web-based discussion forums.
Arianna Usenet Usenet search engine that allows searching, browsing, posting and decoding of articles which are in Italian newsgroups.
Chemie.DE Directory and search engine for information about chemistry. Click on the "search engine" link on the home page to search.
Directory and search engine for biological information.
Biolinks A search engine for scientists, with links to journals, organizations, companies and more. It spiders the web and has human-categorized results.
PSI - Polymer Search on the Internet Search engine for the global polymer, plastic and rubber industries. Includes daily industry news.