Perhaps you should try some spelling variations:
le litterature » la litterature, de litterature, le letterature
test studium » test studies, selbst studium, das studium
di filosofia » e filosofia
des studium » des studiums, das studium, dem studium

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

• If you are trying to use Boolean operators, they must be ALL CAPS: test ((test studium) OR (des studium)) ((di filosofia) OR (la filosofia)) le litterature.
• The words AND, OR and NOT may confuse the search; try adding quotes: "test ((test studium) or (des studium)) ((di filosofia) OR (la filosofia)) le litterature".
• Adding a wildcard symbol may retrieve word variants: test ((test studium) or (des studium)) ((di filosofia) OR (la filosofia)) le litterature*.