Perhaps you should try some spelling variations:
mechanical structures » chemical structures, mathematical structures
mechanical stresses » mechanical stress, mechanical strength
rim international » from international, acm international
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: ((rim international) OR (im internationalen)) centre for ((mechanical stresses) OR (mechanical structures)), courses AND lectures.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((rim international) or (im internationalen)) centre for ((mechanical stresses) OR (mechanical structures)), courses and lectures".
• Adding a wildcard symbol may retrieve word variants: ((rim international) or (im internationalen)) centre for ((mechanical stresses) OR (mechanical structures)), courses and lectures*.