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

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: (((("series estudio urbano.") OR ("serie estudios urbano."))) or ("seis estudios americanos."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("series estudio urbano.") OR ("serie estudios urbano."))) OR ("seis estudios americanos.")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"series estudio urbano.\") OR (\"serie estudios urbano.\"))) or (\"seis estudios americanos.\"))".
• Removing quotes may allow a broader search: (((( series estudio urbano. ) OR ( serie estudios urbano. ))) or ( seis estudios americanos. )).
• Adding a wildcard symbol may retrieve word variants: (((("series estudio urbano.") OR ("serie estudios urbano."))) or ("seis estudios americanos."))*.