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

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