Perhaps you should try some spelling variations:
die filosofica » di filosofia, de filosofia, e filosofica
tests stable » tests table, sets stable, tests scale
filosofica a » filosofica da, filosofica e, filosofica _
a literatura » la literatura, a literature, y literatura
studies die » studie die, studien die, studies does
test table » test tables, tests table, test tabelle

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) OR (test table)) studies die filosofica a literatura.
• Adding a wildcard symbol may retrieve word variants: ((tests stable) or (test table)) studies die filosofica a literatura*.