Perhaps you should try some spelling variations:
mechanical efficiency » technical efficiency
international centre » international theatre, international context, international case
ecological science » biological sciences
clinical science » political science, clinical evidence, medical science
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 for mechanical efficiency, courses AND lectures ) OR ( international centre for ((clinical science) OR (ecological science)), courses AND lectures )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( international centre for mechanical efficiency, courses and lectures ) or ( international centre for ((clinical science) OR (ecological science)), courses and lectures ))".
• Adding a wildcard symbol may retrieve word variants: (( international centre for mechanical efficiency, courses and lectures ) or ( international centre for ((clinical science) OR (ecological science)), courses and lectures ))*.