Perhaps you should try some spelling variations:
"didactics di ricerca" » "didactics _ ricerca", "didactics 2 ricerca", "didactics 3 ricerca", "didactics la ricerca"
"didactics e ricerca" » "didactics _ ricerca", "didactics 2 ricerca", "didactics 3 ricerca", "didactics la ricerca", "didactics e ricerche"

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"didactics e ricerca\") OR (\"didactics di ricerca\"))*".
• Removing quotes may allow a broader search: (( didactics e ricerca ) OR ( didactics di ricerca ))*.