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