Analysis of the Reasons Why Invisible Web Can´t Be Seen and its Effective Retrieval Strategies

Nowadays, Internet goes deep into human beings\´ daily routines and brings us many remarkable conflicts between mass digital information and our limited capabilities of acquiring them. Search engine thus becomes an important channel of obtaining information. But conventional search engines can index less than 16% of the publicly indexable Webs, and the other 84% are "invisible". Moreover, the public information on the Invisible Web is 400-550 times larger than WWW. Thus users are searching only 0.03% of available pages. Therefore, it\´s urgent to seek efficient methods to solve the retrieval problem of Invisible Web. This thesis elaborates the reasons why Invisible Web is invisible, puts forward several effective strategies of hunting up invisible resources, and expects to bring human beings enlightenment in network information retrieval and utilization.