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

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 peruanoss.") or ("leyes estudios urbano."))) or ("los estudios urbanos."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("serie estudios peruanoss.") OR ("leyes estudios urbano."))) OR ("los estudios urbanos.")).
• Removing quotes may allow a broader search: (((( serie estudios peruanoss. ) or ( leyes estudios urbano. ))) or ( los estudios urbanos. )).
• Adding a wildcard symbol may retrieve word variants: (((("serie estudios peruanoss.") or ("leyes estudios urbano."))) or ("los estudios urbanos."))*.