HE Transportation and Communications TK Electrical engineering. Electronics Nuclear engineering 36 QA76 Computer software 7 TA Engineering (General). Civil engineering (General) 7 TE Highway engineering. Roads and pavements 7 QA75 Electronic computers. Computer science 5 TJ Mechanical engineering and machinery 5 HD28 Management. Industrial Management 3 Elections. Electoral systems. Voting 2 VM Naval architecture. Shipbuilding. Marine engineering 2 HD Industries. Land use. Labor 1 HG Finance 1 LC Special aspects of education 1 Research 1 T Technology (General) 1 TC Hydraulic engineering. Ocean engineering 1 TD Environmental technology. Sanitary engineering 1 TL Motor vehicles. Aeronautics. Astronautics 1 Telecommunication industry. Telegraph 1