Perhaps you should try some spelling variations:
agents safety » patients safety, plants safety, accidents safety
del literatur » model literatur, teil literatur, igel literatur
study dem » study demo, study der, study d0m
study de » study die, study der, study d

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: "agents safety ((study de) OR (study dem)) filosofia del literatur".
• Adding a wildcard symbol may retrieve word variants: agents safety ((study de) OR (study dem)) filosofia del literatur*.