Perhaps you should try some spelling variations:
safety studien » safety studies, safety stories
safety study » safety studies, safety stock
a literatura » la literatura, a literature, y literatura
filosofia a » filosofia da, filosofia la, filosofia e

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: "stents ((safety studien) OR (safety study)) la filosofia a literatura*".