Perhaps you should try some spelling variations:
del litterature » de litterature, des litteratures, et litterature
das filosofia » da filosofia, di filosofia, a filosofia
five studies » wave studies, five stories, native studies
test five » test file, test files, least five

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 five studies ((das filosofia) OR (la filosofia)) del litterature".
• Adding a wildcard symbol may retrieve word variants: test five studies ((das filosofia) OR (la filosofia)) del litterature*.