Perhaps you should try some spelling variations:
del literatura » de literatura, pela literatura, da literatura
studien des » studien der, studie des, studien aus
test orale » test oracle, test oral, test oracles
studien ds » studien das, studies ds, studien dd

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: "test orale ((studien ds) OR (studien des)) filosofia del literatura".
• Adding a wildcard symbol may retrieve word variants: test orale ((studien ds) OR (studien des)) filosofia del literatura*.