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

You may be able to get more results by adjusting your search query.

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