有效 距 离 : 27 phrases in 15 subjects |
Air defense | 2 |
Automobiles | 2 |
Aviation | 1 |
Earth sciences | 1 |
Electronics | 1 |
Engineering geology | 1 |
General | 3 |
Military | 1 |
Navigation | 1 |
Oil / petroleum | 1 |
Space | 4 |
Technology | 6 |
Telecommunications | 1 |
Transport | 1 |
Wind Energy | 1 |