Plugin_Search_Parse_ContentOnly.php

class Plugin_Search_Parse_ContentOnly
{
   static public function register() {
        $objHook = Vault_Hook::getInstance();
        $s = __CLASS__;
        $o = new $s;
        $objHook->register($o);
    }
    public function search_parse_assemble(&$search) {
        $search->parts['fq'][] = 'fedora.contentModel:[* TO *]';
    }
}

Plugin_Search_Parse_ContentOnly::register();