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

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 ((("leyes estudios peruanoss.") OR ("seis estudios peruanoss."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("serie estudios urbano.") OR ((("leyes estudios peruanoss.") OR ("seis estudios peruanoss."))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"serie estudios urbano.\") or (((\"leyes estudios peruanoss.\") OR (\"seis estudios peruanoss.\"))))*".
• Removing quotes may allow a broader search: (( serie estudios urbano. ) or ((( leyes estudios peruanoss. ) OR ( seis estudios peruanoss. ))))*.