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

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