Perhaps you should try some spelling variations:
abel literature » al literature, travel literature, tamil literature
fuel literature » level literature, model literature, novel literature
studium 3 » studium _, studium 1, studium im
studium 8 » studium _, studium 1, studium im
test des » test der, test test

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: test des ((studium 3) OR (studium 8)) filosofia ((fuel literature) OR (abel literature)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "test des ((studium 3) or (studium 8)) filosofia ((fuel literature) OR (abel literature))".
• Adding a wildcard symbol may retrieve word variants: test des ((studium 3) or (studium 8)) filosofia ((fuel literature) OR (abel literature))*.