Perhaps you should try some spelling variations:
"series estudios urbano." » "serie estudios urbano.", "tres estudios urbano.", "leyes estudios urbano.", "series estudios urbanos.", "series estudio urbano.", "series estudios peruanos."
"seis estudios urbano." » "seis estudios urbanos.", "seis estudio urbano.", "seis estudios peruanos.", "los estudios urbano.", "dios estudios urbano.", "pons estudios urbano."
"dos estudios urbano." » "dos estudios urbanos.", "dos estudio urbano.", "dos estudios peruanos.", "los estudios 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: (("series estudios urbano.") or ((("seis estudios urbano.") or ("dos estudios urbano."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("series estudios urbano.") OR ((("seis estudios urbano.") OR ("dos estudios urbano.")))).
• Removing quotes may allow a broader search: (( series estudios urbano. ) or ((( seis estudios urbano. ) or ( dos estudios urbano. )))).
• Adding a wildcard symbol may retrieve word variants: (("series estudios urbano.") or ((("seis estudios urbano.") or ("dos estudios urbano."))))*.