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

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