Perhaps you should try some spelling variations:
"dos estudios hispanic." » "dos estudios hispanicos.", "dos estudios hispano.", "dos studies hispanic.", "los estudios hispanic."
"series d'estudis urbans." » "series estudios urbans.", "serie estudios urbans.", "serie estudio urbans.", "series estudio urbano.", "series estudios urbano."
"tres estudios urbanos." » "otros estudios urbanos.", "los 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: (((("series d'estudis urbans.") or ("tres estudios urbanos."))) or ("dos estudios hispanic."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("series d'estudis urbans.") OR ("tres estudios urbanos."))) OR ("dos estudios hispanic."))*.
• Removing quotes may allow a broader search: (((( series d'estudis urbans. ) or ( tres estudios urbanos. ))) or ( dos estudios hispanic. ))*.