Perhaps you should try some spelling variations:
a litterature » la litterature, _ litterature, et litterature
de filosofia » e filosofia, di filosofia, la filosofia
der studium » oder studium, dem studium, des studium
studium de » studium der, studium des, studium die
test » text

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 der studium de filosofia ((a litterature) OR (a literature)).
• Adding a wildcard symbol may retrieve word variants: test der studium de filosofia ((a litterature) or (a literature))*.