Perhaps you should try some spelling variations:
"leyes estudios peruanoss." » "leyes estudios americanoss.", "leyes estudios ensayoss.", "leyes estudios cervantinoss.", "los estudios peruanoss.", "seis estudios peruanoss."
"tres estudios peruanos." » "tres estudios americanos.", "tres estudios ensayos.", "tres estudios cervantinos.", "otros estudios peruanos.", "los estudios peruanos.", "dos estudios peruanos."
"series estudios urbanos." » "serie estudios urbanos.", "seis estudios urbanos.", "sociales 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: (((("leyes estudios peruanoss.") or ("series estudios urbanos."))) or ("tres estudios peruanos."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("leyes estudios peruanoss.") OR ("series estudios urbanos."))) OR ("tres estudios peruanos."))*.
• Removing quotes may allow a broader search: (((( leyes estudios peruanoss. ) or ( series estudios urbanos. ))) or ( tres estudios peruanos. ))*.