TP Chemical technology 144 TA Engineering (General). Civil engineering (General) 28 T Technology (General) 26 TK Electrical engineering. Electronics Nuclear engineering 24 Q Science (General) 16 QA75 Electronic computers. Computer science 15 TJ Mechanical engineering and machinery 15 QD Chemistry 14 QC Physics 10 QA Mathematics 8 R Medicine (General) 4 TD Environmental technology. Sanitary engineering 4 BP Islam. Bahaism. Theosophy, etc 3 HD28 Management. Industrial Management 3 TN Mining engineering. Metallurgy 3 G70.39-70.6 Remote sensing 2 GE Environmental Sciences 2 HD1394-1394.5 Real estate management 2 QH Natural history 2 QH301 Biology 2 TC Hydraulic engineering. Ocean engineering 2 TH Building construction 2 TS Manufactures 2 GB Physical geography 1 H Social Sciences (General) 1 HD30.213 Management information systems. Decision support systems 1 LB Theory and practice of education 1 Q Science 1 QA76 Computer software 1 QP Physiology 1