[GENERAL] Full text search with plain input

Hi,

I would like to use PostgreSQL's FTS functionality.
The user would enter a search text, one or more words.
There is a suitable plainto_tsquery() function, but it's to strict. It
only matches if all words match. What is the best practice to make this
kind of search more "forgiving", so that it matches (with less rank) even
if one of its words match ?

Thanks,
Otto