Perhaps you should try some spelling variations:
"serie estudios urbano." » "serie estudios urbanos.", "serie estudio urbano.", "serie estudios peruanos."
"seis estudios urbano." » "seis estudios urbanos.", "seis estudio urbano.", "seis estudios peruanos.", "dos estudios urbano.", "dios estudios urbano.", "pons estudios urbano."
"los estudios hispano." » "los estudios hispana.", "los estudios hispanic."

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 urbano.") or ("seis estudios urbano."))) or ("los estudios hispano."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("serie estudios urbano.") OR ("seis estudios urbano."))) OR ("los estudios hispano."))*.
• Removing quotes may allow a broader search: (((( serie estudios urbano. ) or ( seis estudios urbano. ))) or ( los estudios hispano. ))*.