TP Chemical technology 156 QD Chemistry 64 QC Physics 55 TJ Mechanical engineering and machinery 51 TA Engineering (General). Civil engineering (General) 32 T Technology (General) 20 Q Science (General) 18 TK Electrical engineering. Electronics Nuclear engineering 13 TS Manufactures 8 R Medicine (General) 6 TD Environmental technology. Sanitary engineering 6 QH Natural history 5 QH301 Biology 5 QP Physiology 4 Unspecified 4 Q Science 3 TN Mining engineering. Metallurgy 2 AC Collections. Series. Collected works 1 G70.39-70.6 Remote sensing 1 HD28 Management. Industrial Management 1 HE Transportation and Communications 1 HF Commerce 1 NA Architecture 1 P Philology. Linguistics 1 QK Botany 1 QR Microbiology 1 R Medicine 1 RA1001 Forensic Medicine. Medical jurisprudence. Legal medicine 1 RC0254 Neoplasms. Tumors. Oncology (including Cancer) 1 RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry 1