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

Try widening your search to All Fields.

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