TK Electrical engineering. Electronics Nuclear engineering 2,865 TA Engineering (General). Civil engineering (General) 2,490 TP Chemical technology 2,052 L Education (General) 2,030 TJ Mechanical engineering and machinery 1,618 QA75 Electronic computers. Computer science 1,558 T Technology (General) 1,005 QA Mathematics 795 Q Science (General) 705 HD28 Management. Industrial Management 681 QD Chemistry 654 QC Physics 576 TH Building construction 372 H Social Sciences (General) 339 QA76 Computer software 338 LB Theory and practice of education 301 HD Industries. Land use. Labor 273 NA Architecture 237 HD1394-1394.5 Real estate management 183 TD Environmental technology. Sanitary engineering 169 Unspecified 164 BP Islam. Bahaism. Theosophy, etc 161 G70.212-70.215 Geographic information system 136 Q Science 127 HF Commerce 114 QH Natural history 113 QH301 Biology 110 TS Manufactures 109 HE Transportation and Communications 103 G Geography (General) 100