Perhaps you should try some spelling variations:
national » nationala (Expand Search), nation (Expand Search), nationen (Expand Search)
nationales » nationalaes (Expand Search), nationes (Expand Search), nationenes (Expand Search), nationalist (Expand Search), nationala (Expand Search), rationalen (Expand Search)
nationale » nationalae (Expand Search), natione (Expand Search), nationene (Expand Search)
nationalen » nationalaen (Expand Search), nationen (Expand Search), nationenen (Expand Search)
nationaler » nationalaer (Expand Search), nationer (Expand Search), nationener (Expand Search), nationala (Expand Search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((national OR nationales) OR nationale) OR (nationalen OR nationaler)) connaissance front~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((national OR nationales) OR nationale) OR (nationalen OR nationaler)) connaissance front".
• Adding a wildcard symbol may retrieve word variants: (((national OR nationales) OR nationale) OR (nationalen OR nationaler)) connaissance front*.