Perhaps you should try some spelling variations:
"series estudios urbano." » "seis estudios urbano.", "tres estudios urbano.", "leyes estudios urbano.", "series estudio urbano.", "series estudios peruanos.", "series d'estudis urbans."
"serie estudios urbanos." » "serie estudio urbanos.", "serie estudios peruanoss.", "serie d'estudis urbanss."
"sociales estudios hispano." » "sociales estudios hispana.", "sociales estudios hispanic."

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 ("serie estudios urbanos."))) or ("sociales estudios hispano."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("series estudios urbano.") OR ("serie estudios urbanos."))) OR ("sociales estudios hispano."))*.
• Removing quotes may allow a broader search: (((( series estudios urbano. ) or ( serie estudios urbanos. ))) or ( sociales estudios hispano. ))*.