Perhaps you should try some spelling variations:
international congress » international conference
international theatre » international treaties, international test, international taxation
international context » international conference
mechanical sciences » mechanical science, technical sciences, chemical sciences
lectures » lecture

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 theatre) OR (international trade))) OR (((international context) OR (international congress)))) for mechanical sciences, courses AND lectures.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((international theatre) OR (international trade))) or (((international context) or (international congress)))) for mechanical sciences, courses and lectures".
• Adding a wildcard symbol may retrieve word variants: ((((international theatre) OR (international trade))) or (((international context) or (international congress)))) for mechanical sciences, courses and lectures*.