TP Chemical technology 80 QD Chemistry 53 TA Engineering (General). Civil engineering (General) 22 R Medicine (General) 12 Q Science (General) 11 QK Botany 8 TD Environmental technology. Sanitary engineering 6 QH Natural history 5 QC Physics 4 QH301 Biology 4 Unspecified 4 TJ Mechanical engineering and machinery 3 QP Physiology 2 T Technology (General) 2 TK Electrical engineering. Electronics Nuclear engineering 2 HD1394-1394.5 Real estate management 1 HV Social pathology. Social and public welfare 1 QH426 Genetics 1 QR Microbiology 1 RA Public aspects of medicine 1 RM Therapeutics. Pharmacology 1 TC Hydraulic engineering. Ocean engineering 1