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

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

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