Perhaps you should try some spelling variations:
a litterature » _ litterature, et litterature, de litterature
da filosofia » la filosofia, di filosofia, a filosofia
des studium » des studiums, das studium, dem studium
studium da » studium das, studium a, studium d
test des » test der, test test

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 des studium da filosofia ((((a litterature) OR (la litterature))) OR (a literature)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "test des studium da filosofia ((((a litterature) OR (la litterature))) or (a literature))".
• Adding a wildcard symbol may retrieve word variants: test des studium da filosofia ((((a litterature) OR (la litterature))) or (a literature))*.