How to add wordpress filter to search?

I'm trying to filter my search result in wordpress.
Does it exist a filter like add_filter('search_result', 'xxxx') ?

When I get the result, I need to apply a second custom filter...

I found this add_action( 'the_post', 'my_the_post_action' ); It loops on result but i don't know how to remove an item...

Any idea ? thanks

via Chebli Mohamed