Perhaps you should try some spelling variations:
stable studien » stadler studien, scale studien, table studies
der filosofia » de filosofia, e filosofia, di filosofia
de literatura » de litterature, y literatura, a literatura
la literatura » la litterature, a literature
tests stable » tests table, sets stable, test table
studien der » studie der, studien die, studenten der

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 der filosofia ((de literatura) OR (la literatura))".
• Adding a wildcard symbol may retrieve word variants: tests stable studien der filosofia ((de literatura) OR (la literatura))*.