Perhaps you should try some spelling variations:
"series estudios andinos." » "series estudios etnicos.", "series estudios ensayos.", "serie estudios andinos.", "tres estudios andinos.", "leyes estudios andinos."
"serie estudio urbanos." » "serie estudio urbano.", "serie estudios urbano.", "serie estudios peruanos.", "serie estudios urbanos.", "serie studia urbanos.", "serie estado urbanos."
"seis estudios urbanos." » "los estudios urbanos.", "dos estudios urbanos.", "dios estudios urbanos."

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

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