Perhaps you should try some spelling variations:
"tres estudios hispanicos." » "tres estudios historicos.", "tres estudios hispano.", "tres estudios islamicos.", "otros estudios hispanicos.", "los estudios hispanicos.", "dos estudios hispanicos."
"seis estudios urbano." » "seis estudios urbanos.", "seis estudios peruanos.", "seis estudios hispano.", "los estudios urbano.", "dos estudios urbano.", "dios estudios urbano."
"series estudio urbano." » "series estudios urbano.", "serie estudio urbano.", "serie estudios urbano.", "series estudios urbanos.", "series espacio urbano."

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