echoes : 254 phrases in 26 subjects |
Acoustics | 3 |
Agriculture | 2 |
Antennas and waveguides | 1 |
Astronomy | 15 |
Communications | 38 |
Computers | 34 |
Construction | 3 |
Earth sciences | 12 |
Electronics | 5 |
General | 7 |
Geophysics | 2 |
Linguistics | 1 |
Measuring instruments | 6 |
Medical | 16 |
Medical appliances | 32 |
Metallurgy | 2 |
Natural resourses and wildlife conservation | 6 |
Optics branch of physics | 3 |
Physics | 44 |
Piezoelectric crystals | 1 |
Power lines | 6 |
Radio | 3 |
Technology | 6 |
Telecommunications | 3 |
Telegraphy | 1 |
Telephony | 2 |