Perhaps you should try some spelling variations:
"tres estudios peruanoss." » "tres estudios urbanos.", "tres estudios urbanoss.", "tres estudios americanoss.", "tres estudios ensayoss.", "otros estudios peruanoss.", "los estudios peruanoss.", "dos estudios peruanoss."
"series estudios peruanos." » "series estudios urbanos.", "series estudios americanos.", "series estudios ensayos.", "serie estudios peruanos.", "seis estudios peruanos.", "leyes estudios peruanos."
"series estudios urbano." » "serie estudios urbano.", "seis estudios urbano.", "leyes estudios urbano.", "series estudios urbanos.", "series estudio urbano.", "series 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: (("tres estudios peruanoss.") or ((("series estudios urbano.") OR ("series estudios peruanos."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("tres estudios peruanoss.") OR ((("series estudios urbano.") OR ("series estudios peruanos.")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"tres estudios peruanoss.\") or (((\"series estudios urbano.\") OR (\"series estudios peruanos.\"))))".
• Removing quotes may allow a broader search: (( tres estudios peruanoss. ) or ((( series estudios urbano. ) OR ( series estudios peruanos. )))).
• Adding a wildcard symbol may retrieve word variants: (("tres estudios peruanoss.") or ((("series estudios urbano.") OR ("series estudios peruanos."))))*.