frequency method

: 84 phrases in 17 subjects

Air defense	8
Architecture	1
Automobiles	1
Aviation	2
Chemistry	3
Earth sciences	9
Electronics	8
Ethnology	1
Explosives and Explosive Ordnance Disposal	1
Geophysics	4
Information technology	5
Metallurgy	4
Oil / petroleum	7
Plastics	1
Rail transport	1
Space	3
Technology	25