Perhaps you should try some spelling variations:
filosofia y » filosofia _, filosofia de, filosofia da
filosofia e » filosofia de, filosofia del
besten der » bestehen der, bestimmen der, bestehens der
studie a » studie am, studie 2, studie 1

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: besten der ((studie a) OR (studie _)) ((filosofia y) OR (filosofia e)) literatura.
• The words AND, OR and NOT may confuse the search; try adding quotes: "besten der ((studie a) or (studie _)) ((filosofia y) OR (filosofia e)) literatura".
• Adding a wildcard symbol may retrieve word variants: besten der ((studie a) or (studie _)) ((filosofia y) OR (filosofia e)) literatura*.