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

You may be able to get more results by adjusting your search query.

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