Perhaps you should try some spelling variations:
"serie estudio urbano." » "serie estudios urbano.", "serie espacio urbano.", "series estudios urbano.", "serie studia urbano.", "serie estado urbano."
"serie estudios urbanos." » "series estudioss urbanos.", "serie studias urbanos.", "serie estados urbanos."
"dos studies spain." » "dos estudies spain.", "dos students spain.", "dos soldiers spain.", "dos estudios spain.", "case studies spain."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("serie estudios urbanos.") or ("serie estudio urbano."))) or ("dos studies spain."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("serie estudios urbanos.") OR ("serie estudio urbano."))) OR ("dos studies spain."))*.
• Removing quotes may allow a broader search: (((( serie estudios urbanos. ) or ( serie estudio urbano. ))) or ( dos studies spain. ))*.