Perhaps you should try some spelling variations:
da literatura » la literatura, a literatura, de literatura
de filosofia » e filosofia, di filosofia, la filosofia
filosofia da » filosofia de, filosofia del, filosofia e
test scale » tests scale, best scale, rest scale
tests safe » tests safety, tests scale, tests space
studies de » studies der, studies die, studies doe

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: ((test scale) OR (tests safe)) studies de filosofia da literatura*.