TA Engineering (General). Civil engineering (General) 22 TJ Mechanical engineering and machinery 18 TK Electrical engineering. Electronics Nuclear engineering 17 TP Chemical technology 16 QA75 Electronic computers. Computer science 15 QA Mathematics 4 T Technology (General) 4 HE Transportation and Communications 2 G70.212-70.215 Geographic information system 1 L Education (General) 1 Q Science (General) 1 QC Physics 1 QD Chemistry 1 QE Geology 1 QM Human anatomy 1 TD Environmental technology. Sanitary engineering 1 TK7885-7895 Computer engineer. Computer hardware 1 TL Motor vehicles. Aeronautics. Astronautics 1 TN Mining engineering. Metallurgy 1 Unspecified 1 VM Naval architecture. Shipbuilding. Marine engineering 1