TK Electrical engineering. Electronics Nuclear engineering 146 TJ Mechanical engineering and machinery 134 TA Engineering (General). Civil engineering (General) 87 TP Chemical technology 63 QA75 Electronic computers. Computer science 49 QA Mathematics 27 HD28 Management. Industrial Management 21 T Technology (General) 20 Q Science (General) 12 QA76 Computer software 11 Unspecified 11 QC Physics 10 TH Building construction 9 G70.212-70.215 Geographic information system 8 TL Motor vehicles. Aeronautics. Astronautics 8 QD Chemistry 7 BP Islam. Bahaism. Theosophy, etc 6 QH Natural history 6 TK7885-7895 Computer engineer. Computer hardware 6 NA Architecture 5 QH301 Biology 5 TC Hydraulic engineering. Ocean engineering 5 HE Transportation and Communications 4 LB Theory and practice of education 4 R Medicine (General) 4 TE Highway engineering. Roads and pavements 4 VM Naval architecture. Shipbuilding. Marine engineering 4 HD1394-1394.5 Real estate management 3 G Geography (General) 2 G109.5 Global Positioning System 2