Perhaps you should try some spelling variations:
de literatura » de litterature, la literatura, y literatura
filosofia de » filosofia del
test de » test der, test des, est de
test d » test do, test der, test des

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 d) OR (test de)) studie _ filosofia de literatura".
• Adding a wildcard symbol may retrieve word variants: ((test d) OR (test de)) studie _ filosofia de literatura*.