$criteria->compare('title',$this->title,$partialMatch=false);

SELECT * FROM tbl_post WHERE title REGEXP '[[:<:]]$this->title[[:>:]]'

if ($this->title)
{
    $criteria->select = 'title';
    $criteria->condition = 'title REGEXP "[[:<:]]:filter_word[[:>:]]"';
    $criteria->params = array(':filter_word'=>$this->title);
}