Perhaps you should try some spelling variations:
"serie estudios hispanicos." » "serie estudios historicos.", "serie estudios hispano.", "serie estudios islamicos."
"tres estudios criticos." » "tres estudios juridicos.", "otros estudios criticos.", "los estudios criticos.", "dos estudios criticos."
"serie estudos hispanos." » "serie estudios hispano.", "serie estilo hispano.", "series estudios hispanos.", "serie estado hispanos.", "serie estudio hispanos."

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 ((("serie estudos hispanos.") OR ("serie estudios hispanicos."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("tres estudios criticos.") OR ((("serie estudos hispanos.") OR ("serie estudios hispanicos.")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"tres estudios criticos.\") or (((\"serie estudos hispanos.\") OR (\"serie estudios hispanicos.\"))))".
• Removing quotes may allow a broader search: (( tres estudios criticos. ) or ((( serie estudos hispanos. ) OR ( serie estudios hispanicos. )))).
• Adding a wildcard symbol may retrieve word variants: (("tres estudios criticos.") or ((("serie estudos hispanos.") OR ("serie estudios hispanicos."))))*.