When you search in preview you tend to get a *lot* of results. They can be a little overwhelming. One way to make the results better is to check the box above the search results that says "Group by section" (sometimes this is called "Group by page"). When you check this box it then shows the relevance and it greatly reduces the number of results since typically the same search term will show up multiple times on a page.

Here's what the search looks like without checking this box:

Preview search results when not grouped

And here's what it looks like after checking this box, much nicer:

Preview search results when grouped