The best place to start is the catalogue. The Library catalogue can be found at http://libsearch.hull.ac.uk (or from the Library homepage). You can search by title, author or subject. If you use the advanced search, you can limit your search to different formats, years, languages, etc.
If you need more help and tips you can check out the Libguide for your subject at http://libguides.hull.ac.uk/