With our migration to Online Documentation, you can search the documentation with any modern browser. This search utility supports sub-string searching (geolog will result in geology, geological etc.) This search engine will give weight results with priority on the title of the topic, and the content second.
If you are familiar with the documentation of GeoModeller then the Table of Contents above will provide you a way to explore the topic tree directly into the Topics.
Alternatively, navigate to support topics by using the library pages split into disciplines of geophysics/intent of the content.