Perhaps you should try some spelling variations:
le literature » e literature, 2e literature, ce literature
filosofia le » filosofia de, filosofia e, filosofia del
tests scale » tests stable, sets scale, tests safe
studien ein » studien eine, studieren ein, studien die
studien e » studien es, studien _, studien 3

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 scale ((studien e) OR (studien ein)) filosofia le literature.
• Adding a wildcard symbol may retrieve word variants: tests scale ((studien e) or (studien ein)) filosofia le literature*.