Perhaps you should try some spelling variations:
international conferentie » internationale conferentie (Expand Search), international conference (Expand Search), nationale conferentie (Expand Search)
internationale seminar » international seminar (Expand Search), internationaal seminarie (Expand Search), internationale meeting (Expand Search)
en internationale » de internationale (Expand Search), het internationaal (Expand Search), eerste internationale (Expand Search)
conferentie de » conference de (Expand Search), conferentie _ (Expand Search), conferentie over (Expand Search)

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: "(( en internationale seminar prize ) OR ( _ international conferentie de ))~".
• Adding a wildcard symbol may retrieve word variants: (( en internationale seminar prize ) OR ( _ international conferentie de ))*.