Perhaps you should try some spelling variations:
"serie studias americanos." » "serie estudios americanos.", "serie estados americanos.", "serie estudios africanos.", "serie studia americanos.", "serie guias americanos.", "serie estudio americanos."
"serie estudios peruanos." » "serie estudios americanos.", "serie estudios ensayos.", "serie estudios cervantinos."
"series estudios urbanos." » "seis estudios urbanos.", "tres estudios urbanos.", "leyes estudios urbanos."

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