Perhaps you should try some spelling variations:
di literatura » de literatura, da literatura, ii literatura
tests safety » test safety, guests safety, stents safety
filosofia di » filosofia de, filosofia da, filosofia del
studie der » studium der
studie de » studie die, studie des, studies de

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 safety ((studie de) OR (studie der)) filosofia di literatura*".