Perhaps you should try some spelling variations:
"serie estudios urbano." » "serie estudio urbano.", "serie estudios peruanos.", "serie estudios hispano."
"series estudios urbanos." » "series estudio urbanos.", "series estudios peruanoss.", "series estudios hispanos.", "seis estudios urbanos.", "tres estudios urbanos.", "sociales estudios urbanos."
"leyes estudios urbano." » "leyes estudio urbano.", "leyes estudios peruanos.", "leyes estudios hispano.", "los estudios urbano.", "seis estudios urbano.", "tres estudios urbano."

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