Perhaps you should try some spelling variations:
"seis estudios americanos." » "seis estudios latinoamericanos.", "dos estudios americanos.", "dios estudios americanos.", "pons estudios americanos."
"los estudios americanos." » "los estudios latinoamericanos."
"series estudios urbano." » "serie estudios urbano.", "tres estudios urbano.", "leyes estudios urbano.", "series estudios urbanos.", "series estudio urbano.", "series estudios peruanos."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("series estudios urbano.") or ((("seis estudios americanos.") OR ("los estudios americanos."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("series estudios urbano.") OR ((("seis estudios americanos.") OR ("los estudios americanos."))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"series estudios urbano.\") or (((\"seis estudios americanos.\") OR (\"los estudios americanos.\"))))*".
• Removing quotes may allow a broader search: (( series estudios urbano. ) or ((( seis estudios americanos. ) OR ( los estudios americanos. ))))*.