If you are looking for a way to hide specific content types from the core Drupal search result then checkout the Search config module. It’s a good idea to use this module if you are using the Content profile module so you can hide the profile node from appearing in your search result.
It does offer other functionality, but I’ll just show you how to hide a content type from the search result. To install this module just go to the Search config project page and download the module. Unzip the module into sites/all/modules directory. Then login with your administration account and enable the module.
To configure the module go to Search settings in the administration section.
Scroll down to the bottom and open the collapsed fieldset called Advanced search configuration.
To remove a content type from the search results, just tick the content type in both search form and search index fieldset.