Isearch is a software system for searching though large amounts of text. 
The system allows a user to very quickly find out what documents are 
available that contain certain words. Unlike older search systems, Isearch 
does not use a list of keywords or an abstract; every word of every 
document can be checked. This allows greatly improved chances of 
discovering new information in old collections.

http://www.cnidr.org/ir/isearch.html

Nassib Nassar