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

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