Perhaps you should try some spelling variations:
"tres estudios hispanic." » "tres estudios hispanicos.", "tres estudios hispano.", "tres studies hispanic.", "otros estudios hispanic.", "los estudios hispanic.", "dos estudios hispanic."
"series estudios urbano." » "serie estudios urbano.", "leyes estudios urbano.", "sociales estudios urbano.", "series estudio urbano.", "series estudios peruanos.", "series estudios hispano."
"seis estudios urbanos." » "seis estudio urbanos.", "seis estudios peruanoss.", "seis estudios hispanos.", "los estudios urbanos.", "dos estudios urbanos.", "dios estudios urbanos."

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