Perhaps you should try some spelling variations:
la literature » la litterature, a literature, la literatura
tests stable » tests table, sets stable, test table
filosofia la » filosofia da, filosofia le, filosofica da
studien ein » studien eine, studieren ein, studien die
studien es » studien aus, studien bei, studien als
studien e » studien _, studien 3, studien 4

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: tests stable ((studien e) OR (((studien es) OR (studien ein)))) filosofia la literature.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tests stable ((studien e) or (((studien es) OR (studien ein)))) filosofia la literature".
• Adding a wildcard symbol may retrieve word variants: tests stable ((studien e) or (((studien es) OR (studien ein)))) filosofia la literature*.