Go ahead! Try it out. Try a really difficult search, like Itby Stephen King or Joyce Carol Oates' book, Thema. The book you were looking for came up right at the top, even without the extra step of doing a title search or limiting by author.
That's the benefit of weighted search results, based on relevance. Just like with Google, what you are looking for gravitates towards to top. If you still need to refine your search results, you can just click on one of the limiters on the left hand side: currently available items only, just what's in a particular library, special topics, by author, or even place.
Want a more precise tool? Not a problem. Koha has an advanced search function that allows searching by multiple author formats (including conference and corporate names), subjects, language, notes, publisher, ISBN, call number, and more. You can limit your search results by item format, by location and availability, and even change the way you want your results to display. If you want to our more resent acquisitions to display first or if you just want them in call number order, it's up to you.