Perhaps you should try some spelling variations:
del literature » model literature, abel literature, fuel literature
fishes studies » fish studies, fisheries studies, figures studies
files studies » films studies, film studies, filho studies
das filosofia » da filosofia, la filosofia, di filosofia

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 ((files studies) OR (fishes studies)) das filosofia del literature".
• Adding a wildcard symbol may retrieve word variants: test ((files studies) OR (fishes studies)) das filosofia del literature*.