Perhaps you should try some spelling variations:
"los estudios peruanoss." » "los estudios peruanos."
"series estudios urbanos." » "serie estudios urbanos.", "seis estudios urbanos.", "leyes estudios urbanos.", "series estudio urbanos.", "series estudios peruanoss.", "series estudios hispanos."
"tres estudios urbano." » "tres estudio urbano.", "tres estudios peruanos.", "tres estudios hispano.", "otros estudios urbano.", "dos estudios urbano.", "dios estudios urbano."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("los estudios peruanoss.") or ("series estudios urbanos."))) or ("tres estudios urbano."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("los estudios peruanoss.") OR ("series estudios urbanos."))) OR ("tres estudios urbano."))*.
• Removing quotes may allow a broader search: (((( los estudios peruanoss. ) or ( series estudios urbanos. ))) or ( tres estudios urbano. ))*.