TP Chemical technology 65 TA Engineering (General). Civil engineering (General) 20 TK Electrical engineering. Electronics Nuclear engineering 15 QA75 Electronic computers. Computer science 12 QD Chemistry 9 TJ Mechanical engineering and machinery 9 T Technology (General) 8 Q Science (General) 7 QA Mathematics 7 R Medicine (General) 4 TD Environmental technology. Sanitary engineering 4 BP Islam. Bahaism. Theosophy, etc 3 HD28 Management. Industrial Management 3 G70.39-70.6 Remote sensing 2 GE Environmental Sciences 2 HD1394-1394.5 Real estate management 2 QC Physics 2 QH Natural history 2 QH301 Biology 2 TH Building construction 2 GB Physical geography 1 HD30.213 Management information systems. Decision support systems 1 LB Theory and practice of education 1 QA76 Computer software 1 QP Physiology 1 SB Plant culture 1 TC Hydraulic engineering. Ocean engineering 1 TE Highway engineering. Roads and pavements 1 TS Manufactures 1 Unspecified 1