http://www.dit.ie/DIT/library/resources/databases/index.html. The link now brings you directly to the WOS general search page and highlights the main user resources.
You can also explore high-impact journals with tools such as cited reference searching and Author Finder.
256 categories thoroughly cover the sciences, social sciences, arts, and humanities. Don't forget to customize your WOS if you're a frequent visitor and avail of the online training in multiple languages.
