Perhaps you should try some spelling variations:
international congress » international conference
international theatre » international treaties, international trade, international test
international centre » international context, international case, international capital
mechanical sciences » technical sciences, mechanical stresses, clinical sciences
mechanical science » mechanism science, clinical science, mechanical stretch
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 centre) OR (international theatre))) OR (international congress)) for ((mechanical sciences) OR (mechanical science)), courses AND lectures.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((international centre) OR (international theatre))) or (international congress)) for ((mechanical sciences) or (mechanical science)), courses and lectures".
• Adding a wildcard symbol may retrieve word variants: ((((international centre) OR (international theatre))) or (international congress)) for ((mechanical sciences) or (mechanical science)), courses and lectures*.