teaching aids 402 electrotechnics 17 civil engineering 17 building constructions 17 technology 15 mechanical engineering 13 circuits theory 13 more ... materials 12 wooden constructions 10 controlling 10 electronics 9 ground structures 9 signals 9 engineering drawing 9 concrete constructions 8 projection 8 safety 7 geodesy 7 measurement 7 engineering 7 telecommunications 7 electronic elements 6 nuclear reactors 6 models 6 elasticity 6 statics 6 buildings (construction) 6 machine parts and joints 6 production 6 CAD 5 less ...