Perhaps you should try some spelling variations:
da literatura » la literatura, a literatura, de literatura
filosofia da » filosofia de, filosofia del, filosofia e
tests safe » tests safety, tests scale, tests space
studie e » studie 2, studie _, studie 3
studie 1 » studie 2, studie _

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 safe ((studie e) OR (studie 1)) filosofia da literatura".
• Adding a wildcard symbol may retrieve word variants: tests safe ((studie e) OR (studie 1)) filosofia da literatura*.