Perhaps you should try some spelling variations:
"seis estudios criticos." » "seis estudios juridicos.", "los estudios criticos.", "dos estudios criticos.", "dios estudios criticos."
"serie estudios hispanos." » "serie estudios hispano.", "serie estudios hispanicos.", "serie estudios espanoles."
"serie studia urbanos." » "serie estudios urbanos.", "serie estudio urbano."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("serie studia urbanos.") or ("serie estudios hispanos."))) or ("seis estudios criticos."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("serie studia urbanos.") OR ("serie estudios hispanos."))) OR ("seis estudios criticos.")).
• Removing quotes may allow a broader search: (((( serie studia urbanos. ) or ( serie estudios hispanos. ))) or ( seis estudios criticos. )).
• Adding a wildcard symbol may retrieve word variants: (((("serie studia urbanos.") or ("serie estudios hispanos."))) or ("seis estudios criticos."))*.