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