Perhaps you should try some spelling variations:
stable studien » stadler studien, scale studien, table studies
tests stable » tests table, sets stable, test table
filosofia de » filosofia del
studien die » studie die, studien der
filosofia e » filosofia del

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "tests stable studien die ((filosofia e) OR (filosofia de)) literatura*".