TK Electrical engineering. Electronics Nuclear engineering 42 TP Chemical technology 21 QA75 Electronic computers. Computer science 18 QA Mathematics 13 QD Chemistry 11 TA Engineering (General). Civil engineering (General) 11 L Education (General) 9 Q Science (General) 9 TJ Mechanical engineering and machinery 9 T Technology (General) 7 QA76 Computer software 6 QC Physics 6 LB Theory and practice of education 3 QH Natural history 2 TD Environmental technology. Sanitary engineering 2 BP Islam. Bahaism. Theosophy, etc 1 GV Recreation Leisure 1 H Social Sciences (General) 1 HD28 Management. Industrial Management 1 HD30.213 Management information systems. Decision support systems 1 HE Transportation and Communications 1 HJ Public Finance 1 LB2300 Higher Education 1 R Medicine (General) 1 S Agriculture (General) 1 TE Highway engineering. Roads and pavements 1 TH Building construction 1 TK5101-6720 Telecommunication 1 TK7885-7895 Computer engineer. Computer hardware 1 TX Home economics 1