Perhaps you should try some spelling variations:
da filosofia » la filosofia, di filosofia, a filosofia
des studium » des studiums, das studium, dem studium
filosofia a » filosofia da, filosofia la, filosofia e
de studium » dem studium, d studium, oder studium

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: "est ((de studium) OR (des studium)) da filosofia a literature*".