Although Library Search provides the widest possible search of UCSC resources, it's not comprehensive. You also have access to hundreds of article databases—some covering multiple subject areas, most dedicated to specific areas of study—that offer more targeted searching.
To assist you in selecting databases appropriate for your discipline, your UCSC librarians have created research guides and guides for specific courses, as well as special-topics guides to help with more general research issues like distinguishing between primary and secondary, and popular and scholarly, sources.