obstruction: 77 phrases in 14 subjects |
Agriculture | 4 |
Antennas and waveguides | 1 |
Chemistry | 1 |
Fish farming pisciculture | 1 |
General | 15 |
Health care | 5 |
Law | 3 |
Life sciences | 4 |
Medical | 33 |
Natural sciences | 1 |
Paleontology | 2 |
Sailing | 1 |
Transport | 4 |
Water resources | 2 |