Perhaps you should try some spelling variations:
"series estudios espanoles." » "series estudios espaciales.", "series judios espanoles.", "series estudiantes espanoles.", "serie estudios espanoles.", "seis estudios espanoles.", "leyes 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."

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