FIT is searchable by any one or a combination of the following:
keywords drawn from the official, popular and alternative
titles which have been used for each treaty
additional keywords relevant to the subject matter
or organisations associated with the treaty
the date on which the treaty was concluded
the place where the treaty was concluded
For example, a free-text search for "genocide" will redirect you to the Convention on the Prevention and Punishment of the Crime of Genocide. When you click on the Convention, you'll discover that the treaty was concluded on 9/12/1958 in New York, and is published at 78 UNTS 277 (and many other places). There are also several links that will take you to the full-text of the convention.
For more resources related to treaty research, including a drafting history (travaux preparatoires) research guide and an annotated list of databases, see the Yale Foreign and International Resources page.