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