Perhaps you should try some spelling variations:
la literatura » la litterature, a literature
peer studie » peer studies, peers studien, der studie
4 filosofia » e filosofia, y filosofia, _ filosofia
a filosofia » la filosofia, e filosofia, di filosofia
best peer » best peere, best peep, best paper

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: best peer studie ((4 filosofia) OR (a filosofia)) la literatura.
• Adding a wildcard symbol may retrieve word variants: best peer studie ((4 filosofia) or (a filosofia)) la literatura*.