TA Engineering (General). Civil engineering (General) 110 TE Highway engineering. Roads and pavements 57 TJ Mechanical engineering and machinery 22 HE Transportation and Communications 18 TK Electrical engineering. Electronics Nuclear engineering 16 QA75 Electronic computers. Computer science 10 TL Motor vehicles. Aeronautics. Astronautics 9 TH Building construction 8 HD28 Management. Industrial Management 6 G70.212-70.215 Geographic information system 4 G70.39-70.6 Remote sensing 4 HD Industries. Land use. Labor 4 HT101-395 Sociology, Urban 4 NA Architecture 4 Unspecified 4 QA Mathematics 3 TD Environmental technology. Sanitary engineering 3 TH434-437 Quantity surveying 3 TP Chemical technology 3 G154.9-155.8 Travel and state. Tourism 2 GE Environmental Sciences 2 HD1394-1394.5 Real estate management 2 NA9000-9284 City planning 2 QA76 Computer software 2 QE Geology 2 T Technology (General) 2 BP Islam. Bahaism. Theosophy, etc 1 GT Manners and customs 1 H Social Sciences (General) 1 HC Economic History and Conditions 1