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

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