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