Perhaps you should try some spelling variations:
opto mechatronics » opto mechatronic, _ optomechatronics, opto mechanics
2c mechatronics » c mechatronics, etc mechatronics, 1 mechatronics
_ mechatronics » _ mechanics
2c robotics » 2 robotics, 21 robotics, 29 robotics
26 robotics » 6 robotics, 2 robotics, 26 robotic
2 robotic » 12 robotic, _ robotic, 3 robotic

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: %22control%((((2c robotics) OR (2 robotic))) OR (26 robotics))%((2c mechatronics) OR (((_ mechatronics) OR (opto mechatronics))))%22.
• Adding a wildcard symbol may retrieve word variants: %22control%((((2c robotics) or (2 robotic))) or (26 robotics))%((2c mechatronics) or (((_ mechatronics) or (opto mechatronics))))%22*.