Perhaps you should try some spelling variations:
2c mechatronics » c mechatronics, etc mechatronics, _ mechatronics
2c robotics » 29 robotics, c robotics, 2.1 robotics
21 robotics » 2.1 robotics, 11 robotics, 21 robotic
26 robotics » 6 robotics, 26 robotic, 16 robotics
1 robotics » _ robotics, a robotics, 6 robotics
2 robotics » _ robotics, a robotics, 6 robotics
2 robotic » 12 robotic, _ robotic, 3 robotic

Try widening your search to All Fields.

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 (((21 robotics) OR (1 robotics))))) OR (((2 robotics) OR (2 robotic))))) OR (26 robotics))%2c mechatronics%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22control%((((((2c robotics) or (((21 robotics) OR (1 robotics))))) or (((2 robotics) or (2 robotic))))) or (26 robotics))%2c mechatronics%22".
• Adding a wildcard symbol may retrieve word variants: %22control%((((((2c robotics) or (((21 robotics) OR (1 robotics))))) or (((2 robotics) or (2 robotic))))) or (26 robotics))%2c mechatronics%22*.