Perhaps you should try some spelling variations:
"estudios visuales de." » "estudios sociales de.", "estudios visual de.", "estudios visuales en.", "estudios visuales y."
"entorn virtual tic." » "entorno virtual tic.", "entorno victual tic.", "entorno virtuales tic.", "entorn virtuales tic.", "entorn virtual iii.", "entorn virtual guia."
"entorno digital oecc." » "entorno digitales oecc.", "entorno digital de.", "entorno digital en."

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: (("entorno digital oecc.") OR ((("entorn virtual tic.") OR ("estudios visuales de."))))~.
• Removing quotes may allow a broader search: (( entorno digital oecc. ) or ((( entorn virtual tic. ) or ( estudios visuales de. ))))~.
• Adding a wildcard symbol may retrieve word variants: (("entorno digital oecc.") or ((("entorn virtual tic.") or ("estudios visuales de."))))*.