TK Electrical engineering. Electronics Nuclear engineering 56 TJ Mechanical engineering and machinery 31 QA75 Electronic computers. Computer science 24 TA Engineering (General). Civil engineering (General) 20 QA76 Computer software 6 G70.212-70.215 Geographic information system 5 QA Mathematics 5 T Technology (General) 5 Q Science (General) 4 QH Natural history 4 HD28 Management. Industrial Management 3 HE Transportation and Communications 3 TP Chemical technology 3 G70.39-70.6 Remote sensing 2 HD Industries. Land use. Labor 2 R Medicine (General) 2 TL Motor vehicles. Aeronautics. Astronautics 2 Unspecified 2 VM Naval architecture. Shipbuilding. Marine engineering 2 G Geography (General) 1 GE Environmental Sciences 1 Geoinformation and Real Estate 1 HD1394-1394.5 Real estate management 1 HF Commerce 1 HG Finance 1 QE Geology 1 QH301 Biology 1 QR Microbiology 1 T58.5-58.64 Information technology 1 T58.6-58.62 Management information systems 1