频谱分析 : 103 phrases in 15 subjects |
Air defense | 11 |
Aviation | 5 |
Business | 1 |
Earth sciences | 1 |
Electronics | 30 |
General | 1 |
Geophysics | 2 |
Metallurgy | 4 |
Nautical | 2 |
Nursing | 1 |
Oil / petroleum | 4 |
Otorhinolaryngology | 1 |
Space | 9 |
Technology | 30 |
Telecommunications | 1 |