search in serialized string

Hi list, I have a form to post resumes. In one parte the user have a option to choose up to 5 languages and his knowledge in it. example : english: basic advanced .... My problem is that was stored serialized in the BD and now I need to do a search by language and knowledge. How can I do this. I've tried everything unsuccessfully. example: search english advanced. If the user have english basic and another advanced he/her appear in the search. Thank's in advance Rodrigo