Check if you really need to use partial word matching for your particular search. Try both american and british spelling if your search terms are in English. Check the syntax of your query. In particular, many clients forget the boolean operators. Make sure you did not only search for plural forms of nouns where the singular form would be interesting, too.
Hyphenation seems to be pretty arbitrary for many technical terms.
If you still did not succeed, you should try to relax your query if you are in a subarea of the bibliography collection. For instance, if you are in the Database section you might not need to include the term database in your query. The organization of the bibliographies into sections is not as clearcut as it might seem, there exists a considerable overlap between them. As you go higher in the hierarchy you include more and more sections into your search. If you tried all of the above and still could not find what you were looking for then the bibliography collection probably does not contain it.