Perhaps you should try some spelling variations:
safety studien » safety studies, safety study, safety stories
stents safety » agents safety, events safety, tenth safety
di filosofia » la filosofia, e filosofia
de filosofia » e filosofia, la filosofia, a filosofia
a literatura » la literatura, a literature, y literatura

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: stents safety studien ((di filosofia) OR (de filosofia)) a literatura.
• Adding a wildcard symbol may retrieve word variants: stents safety studien ((di filosofia) or (de filosofia)) a literatura*.