频率范 围 : 37 phrases in 13 subjects |
Air defense | 4 |
Aviation | 4 |
Communications | 2 |
Electronics | 3 |
General | 1 |
Information technology | 1 |
Otorhinolaryngology | 1 |
Piezoelectric crystals | 3 |
Project management | 1 |
Shipbuilding | 1 |
Space | 5 |
Technology | 6 |
Telecommunications | 5 |