Hi there
If you enable the Table of Contents, it may contain a search field.
I believe. however, that all it will do is search the actual text. You cannot specify hidden "keywords". Although, I do suppose you could use transparent Text Captions with the text configured to match the background in order to fashion them. Another possibility that I've not tested is to just put the keywords on Text Captions, then ensure the captions are hidden. I'll have to test that. And I just did and it seems to work! At least it works in the Captivate preview.
Cheers... Rick