Perhaps you should try some spelling variations:
"estudios visuales de." » "estudios sociales de.", "estudios visual de.", "estudios visuales en.", "estudios visuales y."
"entorno virtuales tic." » "entornos virtuales tic.", "entorno virtual tic.", "entornos visuales tic.", "entorno virtuales de.", "entorno virtuales en.", "entorno virtuales y."
"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 ((("entorno virtuales tic.") OR ("estudios visuales de."))))~.
• Removing quotes may allow a broader search: (( entorno digital oecc. ) or ((( entorno virtuales tic. ) or ( estudios visuales de. ))))~.
• Adding a wildcard symbol may retrieve word variants: (("entorno digital oecc.") or ((("entorno virtuales tic.") or ("estudios visuales de."))))*.