Perhaps you should try some spelling variations:
la literatura » la litterature, a literature
filosofia la » filosofia da, filosofia le, filosofica da
tests scale » tests stable, sets scale, tests safe
studien das » studie das, studien des, studien der
studien l » 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 scale ((studien das) OR (studien l)) filosofia la literatura*.