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