First way =>You can bookmark your bookmark page,
see all the bookmarks , are stored in html page.,
For example in my system the path to bookmarks page is
so open it in web browser,
Now press Ctrl+F and now you can search any bookmarks.
there is one good feature about the highlighting, so you can just click on highlight and scroll to see, (no need to click on next and next)
2 nd wayGoogle toolbar provide the way you can search
see this window , you can see it,