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

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