Perhaps you should try some spelling variations:
international astronomical » international economics, international economic
economique internationale » economics international, economy international
politique internationale » policy international
astronomy observatory » astronomy observations, astronomical observatory

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: ((international astronomical) OR (observations astronomical)) union/union ((astronomy observatory) OR (((economique internationale) OR (politique internationale))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((international astronomical) or (observations astronomical)) union/union ((astronomy observatory) or (((economique internationale) OR (politique internationale))))*".