The Vtiger global search and list view search functions get all the attention, but the little noticed Vtiger Advanced Search can be pretty handy especially if you like to transition some of your searches into Filters/Views.

The Advanced Search is located just to the right of the global search.  Click on it and the search window opens — it is the the same search module as for filters so it should be familiar.  Execute your search — the search results show in the global search results window — and if you like it, save your search as a Filter/View with one click.