Perhaps you should try some spelling variations:
"leyes estudios peruanoss." » "leyes estudios urbanos.", "leyes estudios urbanoss.", "leyes estudios americanoss.", "leyes estudios ensayoss.", "series estudios peruanoss.", "los estudios peruanoss.", "seis estudios peruanoss."
"serie estudios peruanos." » "serie estudios urbanos.", "serie estudios americanos.", "serie estudios ensayos."
"serie estudios urbano." » "serie estudios urbanos.", "serie estudio urbano.", "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: (((("serie estudios urbano.") OR ("serie estudios peruanos."))) or ("leyes estudios peruanoss."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("serie estudios urbano.") OR ("serie estudios peruanos."))) OR ("leyes estudios peruanoss."))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"serie estudios urbano.\") OR (\"serie estudios peruanos.\"))) or (\"leyes estudios peruanoss.\"))*".
• Removing quotes may allow a broader search: (((( serie estudios urbano. ) OR ( serie estudios peruanos. ))) or ( leyes estudios peruanoss. ))*.