Perhaps you should try some spelling variations:
international astronomical » international economics, international economic
autonomie internationaler » theorie internationaler, akteure internationaler, economies international
economique internationale » economics international, economy international, politique internationale

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: "((international astronomical) OR (observations astronomical)) union/union ((autonomie internationaler) OR (economique internationale))".
• Adding a wildcard symbol may retrieve word variants: ((international astronomical) OR (observations astronomical)) union/union ((autonomie internationaler) OR (economique internationale))*.