Perhaps you should try some spelling variations:
"seis estudios urbano." » "seis estudios urbanos.", "seis estudios peruanos.", "seis d'estudis urbans.", "los estudios urbano.", "dios estudios urbano.", "pons estudios urbano."
"series estudio urbano." » "series estudios urbano.", "serie estudio urbano.", "serie estudios urbano.", "series estudios urbanos.", "series espacio urbano."
"dos estudios hispano." » "los estudios hispano.", "dos estudios hispana.", "dos 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: (((("seis estudios urbano.") or ("series estudio urbano."))) or ("dos estudios hispano."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("seis estudios urbano.") OR ("series estudio urbano."))) OR ("dos estudios hispano.")).
• Removing quotes may allow a broader search: (((( seis estudios urbano. ) or ( series estudio urbano. ))) or ( dos estudios hispano. )).
• Adding a wildcard symbol may retrieve word variants: (((("seis estudios urbano.") or ("series estudio urbano."))) or ("dos estudios hispano."))*.