Perhaps you should try some spelling variations:
stents safety » agents safety, events safety, tests safety
del literatur » model literatur, teil literatur, igel literatur
tenth safety » heath safety, kent safety, ninth safety
di filosofia » la filosofia, e filosofia
study di » study die, study d, study d3

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) OR (tenth safety)) study di filosofia del literatur".
• Adding a wildcard symbol may retrieve word variants: ((stents safety) OR (tenth safety)) study di filosofia del literatur*.