TJ Mechanical engineering and machinery 96 TP Chemical technology 73 TA Engineering (General). Civil engineering (General) 67 TK Electrical engineering. Electronics Nuclear engineering 53 QD Chemistry 24 QC Physics 23 TS Manufactures 18 TH Building construction 17 Q Science (General) 14 HD28 Management. Industrial Management 11 QA75 Electronic computers. Computer science 8 T Technology (General) 7 Unspecified 6 HD Industries. Land use. Labor 5 QA76 Computer software 5 L Education (General) 4 QA Mathematics 4 TD Environmental technology. Sanitary engineering 4 HD61 Risk Management 3 LB Theory and practice of education 3 QH Natural history 3 G Geography (General) 2 G70.39-70.6 Remote sensing 2 GE Environmental Sciences 2 HT101-395 Sociology, Urban 2 NA Architecture 2 QE Geology 2 R Medicine (General) 2 TC Hydraulic engineering. Ocean engineering 2 G70.212-70.215 Geographic information system 1