Perhaps you should try some spelling variations:
del litterature » de litterature, des litteratures, et litterature
native studies » narrative studies, normative studies, invasive studies
das filosofia » da filosofia, la filosofia, di filosofia
five studies » wave studies, five stories, curve studies

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