Perhaps you should try some spelling variations:
"series estudios americanos." » "series estudios latinoamericanos.", "serie estudios americanos.", "seis estudios americanos.", "tres estudios americanos."
"reales estudios urbano." » "reales estudio urbano.", "rurales estudios urbano.", "locales estudios urbano.", "reales estudios urbanos.", "reales estudios peruanos."
"series espacio urbano." » "series spain urbano.", "versus espacio urbano.", "sociales espacio urbano.", "series espacio urbanismo."

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

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