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