Perhaps you should try some spelling variations:
"series d'estudis urbans." » "series estudios urbans.", "serie estudios urbans.", "serie estudio urbans.", "series estudios urbanos.", "series estudio urbano."
"leyes estudios urbano." » "leyes estudios urbanos.", "leyes estudio urbano.", "leyes estudios peruanos.", "series estudios urbano.", "los estudios urbano.", "seis estudios urbano."
"tres estudios hispano." » "otros estudios hispano.", "los estudios hispano.", "dos estudios hispano.", "tres estudios hispana.", "tres estudios hispanic."

Try widening your search to All Fields.

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