Perhaps you should try some spelling variations:
"tres studies hispanic." » "tres estudios hispanicos.", "tres estudios hispano.", "tres studies spain.", "tres estudios hispanic.", "cases studies hispanic.", "tres ataudes hispanic."
"tres estudioss urbano." » "tres estudios urbano.", "tres estudios urbanos.", "tres estudio urbano.", "tres estadios urbano.", "otros estudios urbano."
"serie espacio urbanismo." » "serie desafio urbanismo.", "serie estado urbanismo.", "serie estudio urbanismo."

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: (((("tres estudioss urbano.") OR ("serie espacio urbanismo."))) OR ("tres studies hispanic."))~.
• Removing quotes may allow a broader search: (((( tres estudioss urbano. ) or ( serie espacio urbanismo. ))) or ( tres studies hispanic. ))~.
• Adding a wildcard symbol may retrieve word variants: (((("tres estudioss urbano.") or ("serie espacio urbanismo."))) or ("tres studies hispanic."))*.