Perhaps you should try some spelling variations:
de literatura » de litterature, la literatura, y literatura
tests stable » tests table, sets stable, test table
de filosofia » e filosofia, di filosofia, la filosofia
filosofia de » filosofia del
sets scale » sets scaled, sets scales, set scale
studien de » studien der, studien die, studien des

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 (sets scale)) studien de filosofia de literatura.
• Adding a wildcard symbol may retrieve word variants: ((tests stable) or (sets scale)) studien de filosofia de literatura*.