Perhaps you should try some spelling variations:
"seis estudios hispanos." » "seis estudios hispanicos.", "seis estudios espanoles.", "seis estudios lesbianos.", "los estudios hispanos.", "dos estudios hispanos.", "dios estudios hispanos."
"tres estudios criticos." » "tres estudios juridicos.", "otros estudios criticos.", "los estudios criticos.", "dos estudios criticos."
"series estudios hispano." » "serie estudios hispano.", "leyes estudios hispano.", "sociales estudios hispano."

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