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

Try widening your search to All Fields.

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 ("seis estudios peruanoss."))) or ("series estudio urbano."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("tres estudios peruanoss.") OR ("seis estudios peruanoss."))) OR ("series estudio urbano.")).
• Removing quotes may allow a broader search: (((( tres estudios peruanoss. ) or ( seis estudios peruanoss. ))) or ( series estudio urbano. )).
• Adding a wildcard symbol may retrieve word variants: (((("tres estudios peruanoss.") or ("seis estudios peruanoss."))) or ("series estudio urbano."))*.