Within the research process patent applications are often the first published account of the invention and it may also be the only published account. About 60 % of the information described in patents are not published elsewhere.
When searching in patent databases using notations of the International Patent Classification is a good tool to find subject specific patents which are often described in the title or the patent itself very global.

Patent Databases

International Patent Classification

Older patents are often found only when searching for the exact patent number. Search in database fields like title, inventor, abstract, notation of IPC or even full text is often only possible starting from a distinct year which depends of database and country of origin of the patent.

More about patents

Subject librarian: Thomas Hapke