Perhaps you should try some spelling variations:
"series estudios peruanoss." » "series estudios peruanos.", "serie estudios peruanoss.", "seis estudios peruanoss.", "leyes estudios peruanoss."
"otros estudios hispano." » "los estudios hispano.", "dos estudios hispano.", "etnicos estudios hispano."
"tres estudios urbanos." » "los estudios urbanos.", "dos estudios urbanos.", "dios estudios urbanos.", "tres estudios 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: (("otros estudios hispano.") or ((("series estudios peruanoss.") or ("tres estudios urbanos."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("otros estudios hispano.") OR ((("series estudios peruanoss.") OR ("tres estudios urbanos.")))).
• Removing quotes may allow a broader search: (( otros estudios hispano. ) or ((( series estudios peruanoss. ) or ( tres estudios urbanos. )))).
• Adding a wildcard symbol may retrieve word variants: (("otros estudios hispano.") or ((("series estudios peruanoss.") or ("tres estudios urbanos."))))*.