Problems in the Retrieval of Information

Databases and catalogues are sometimes huge, consequently search results can sometimes be huge too.
The only way to be 100% certain you have retrieved all the relevant references on a particular search topic is to download the entire database, which is not a very practical thing to do!
Results will always have the search words you entered, but not necessarily the desired context.
Although it is easy to attribute intelligence to computers, retrieval engines for catalogues and databases are not intelligent (at least not those in general use) so they do not know what you mean when you enter search words, thus remember garbage in, garbage out!
Search tactics must be employed systematically and strategically in order to maximize the number of relevant references and minimize the number of non-relevant references.