If you are a student, or a researcher of any kind, you must have puzzled your way through the mazes of the internet. Perhaps you are looking for that elusive document you were sure was available online, only to become less and less sure as dozens of hours still did not produce the document. You need an intro. to the world of the deep web, which is the web of important data lurking just below the top layer of interesting or not so interesting websites.
The internet where you browse for stuff is the extranet. There are also thousands of intranets, local area internets, available to the select few in a business, a library or any other organizations. The intranet is part of the deep web; and to all accounts, it is over 90 percent of the total internet. Zillions of important documents lie in the intranet, forever eluding the researcher who does not know how to access it.
To get access to this deep web, you need one of three things; you need a password, you need a hack, or you need to get lucky. Passwords, as we all know, cost money. For example, students will know about the Elsevier publishing house that stores millions of journal articles in its database. You want one, you have to pay for it. Hacking doesn’t cost you money, but it is a criminal offense, and unless you are very good (nobody really is), stay away from it.
What remains is luck, and this happens this way. Most major documents are in pdf format. Suppose one of these elusive documents somehow managed to surface in Google. Use the filetype pdf syntax in Google to find these documents. Often, when a simple search will give you a bunch of useless files, a pdf search will get you the gold.