TA Engineering (General). Civil engineering (General) 586 TP Chemical technology 532 TK Electrical engineering. Electronics Nuclear engineering 456 TJ Mechanical engineering and machinery 291 QD Chemistry 221 QA75 Electronic computers. Computer science 220 QC Physics 178 HD28 Management. Industrial Management 130 Q Science (General) 128 QA Mathematics 115 L Education (General) 111 LB Theory and practice of education 92 TH Building construction 85 T Technology (General) 71 TD Environmental technology. Sanitary engineering 52 G70.212-70.215 Geographic information system 51 Unspecified 49 HD1394-1394.5 Real estate management 48 NA Architecture 48 HD Industries. Land use. Labor 46 QA76 Computer software 46 QH Natural history 42 QH301 Biology 34 R Medicine (General) 26 TS Manufactures 25 BP Islam. Bahaism. Theosophy, etc 24 HE Transportation and Communications 24 TC Hydraulic engineering. Ocean engineering 22 TE Highway engineering. Roads and pavements 21 TK7885-7895 Computer engineer. Computer hardware 21