Perhaps you should try some spelling variations:
filosoficos a » filosoficos e, filosoficos de, filosofico e
filosofico a » filosofico e, filosofica da, filosofico de
zu studie » zu studien, eu studies, zu studium
studie y » studie 2, studie _, studie 1
test zu » test zur, tests zu, test zum

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "test zu studie y ((filosoficos a) OR (filosofico a)) literatura*".