TK Electrical engineering. Electronics Nuclear engineering 31 TA Engineering (General). Civil engineering (General) 28 TP Chemical technology 20 TJ Mechanical engineering and machinery 15 QA75 Electronic computers. Computer science 13 QC Physics 7 HD28 Management. Industrial Management 6 L Education (General) 5 QA Mathematics 5 LB Theory and practice of education 3 QA76 Computer software 3 HD Industries. Land use. Labor 2 HT101-395 Sociology, Urban 2 NA Architecture 2 QE Geology 2 TD Environmental technology. Sanitary engineering 2 TH Building construction 2 TH434-437 Quantity surveying 2 HB Economic Theory 1 HE Transportation and Communications 1 HF Commerce 1 QH Natural history 1 S Agriculture (General) 1 TE Highway engineering. Roads and pavements 1 TL Motor vehicles. Aeronautics. Astronautics 1 TR Photography 1 TS Manufactures 1 Unspecified 1 Z Bibliography. Library Science. Information Resources 1 ZA4050 Electronic information resources 1