Perhaps you should try some spelling variations:
filosofia la » filosofia le, filosofica da, filosofia das
filosofia da » filosofia de, filosofia del, filosofia e
test items » test systems
studie die » studie der
studie di » studie d, studie de, studie der

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 items ((studie di) OR (studie die)) ((filosofia la) OR (filosofia da)) literatura.
• The words AND, OR and NOT may confuse the search; try adding quotes: "test items ((studie di) or (studie die)) ((filosofia la) OR (filosofia da)) literatura".
• Adding a wildcard symbol may retrieve word variants: test items ((studie di) or (studie die)) ((filosofia la) OR (filosofia da)) literatura*.