Perhaps you should try some spelling variations:
"entorno virtuales oecc." » "entornos virtuales oecc.", "entorno virtual oecc.", "entornos visuales oecc.", "entorno virtuales de.", "entorno virtuales en.", "entorno virtuales tic."
"estudios visuales oecc." » "estudios sociales oecc.", "estudios visuales en.", "estudios visuales de."
"estudios visuales del." » "estudios sociales del.", "estudios visuales de.", "estudios visual del.", "estudios visuales en."

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: (("entorno virtuales oecc.") or ((("estudios visuales oecc.") OR ("estudios visuales del."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("entorno virtuales oecc.") OR ((("estudios visuales oecc.") OR ("estudios visuales del.")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"entorno virtuales oecc.\") or (((\"estudios visuales oecc.\") OR (\"estudios visuales del.\"))))".
• Removing quotes may allow a broader search: (( entorno virtuales oecc. ) or ((( estudios visuales oecc. ) OR ( estudios visuales del. )))).
• Adding a wildcard symbol may retrieve word variants: (("entorno virtuales oecc.") or ((("estudios visuales oecc.") OR ("estudios visuales del."))))*.