TK Electrical engineering. Electronics Nuclear engineering 222 TP Chemical technology 169 TJ Mechanical engineering and machinery 133 TA Engineering (General). Civil engineering (General) 64 QA75 Electronic computers. Computer science 47 T Technology (General) 39 QD Chemistry 32 QA Mathematics 21 Q Science (General) 15 TS Manufactures 10 QH Natural history 9 HD28 Management. Industrial Management 7 Machine design and drawing 7 TH Building construction 7 Unspecified 6 QC Physics 5 R Medicine (General) 5 L Education (General) 4 NA Architecture 4 Optimisation 4 Optimization 4 T58.5-58.64 Information technology 4 TD Environmental technology. Sanitary engineering 4 TE Highway engineering. Roads and pavements 4 Antennas 3 G70.212-70.215 Geographic information system 3 HD Industries. Land use. Labor 3 HD28-70 Management. Industrial Management 3 LB Theory and practice of education 3 Neural networks (Computer science) 3