TK Electrical engineering. Electronics Nuclear engineering 222 TP Chemical technology 169 TJ Mechanical engineering and machinery 109 TA Engineering (General). Civil engineering (General) 64 QA75 Electronic computers. Computer science 47 T Technology (General) 39 QD Chemistry 32 QA Mathematics 21 Q Science (General) 14 TS Manufactures 10 QH Natural history 9 HD28 Management. Industrial Management 7 TH Building construction 7 Unspecified 6 QC Physics 5 L Education (General) 4 NA Architecture 4 R Medicine (General) 4 T58.5-58.64 Information technology 4 G70.212-70.215 Geographic information system 3 HD Industries. Land use. Labor 3 LB Theory and practice of education 3 Q Science 3 QA76 Computer software 3 TC Hydraulic engineering. Ocean engineering 3 TE Highway engineering. Roads and pavements 3 TK7885-7895 Computer engineer. Computer hardware 3 G Geography (General) 2 H Social Sciences (General) 2 QR Microbiology 2