That's because most search engines don't even know this world exists. Lycos is one of the traditional search engines that includes an Invisible Web Catalog, which holds a directory of more than 10,000 searchable databases. This site gives you access to more than 15,000 academic resources, electronic journals and books, on-line library card catalogs, and directories of researchers. This site will bring you to other reviewed sites that collect and organize Web pages that focus on particular subjects.
Virtual libraries are resources that contain reviewed and evaluated Web resources.
Virtual libraries collect Web sites that cover particular subjects and specialized databases. This site contains a history of the Internet. Best to use when looking for a narrow term or phrase or name that is unlikely to have many whole sites devoted to it. There is a photo search engine located at this site called Virage. This site is great because it allows you to ask questions in plain English.