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