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

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