Perhaps you should try some spelling variations:
"dos estudios hispanic." » "dos estudios hispanicos.", "dos estudios hispano.", "dos studies hispanic.", "los estudios hispanic."
"serie estudios peruanos." » "serie estudios urbanos.", "serie estudios americanos.", "serie estudios ensayos."
"series estudios urbano." » "seis estudios urbano.", "tres estudios urbano.", "leyes estudios urbano.", "series estudios urbanos.", "series estudio urbano.", "series estudios hispano."

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