TP Chemical technology QD Chemistry 19 T Technology (General) 10 Q Science (General) 9 TA Engineering (General). Civil engineering (General) 8 TJ Mechanical engineering and machinery 7 QH301 Biology 5 TN Mining engineering. Metallurgy 4 Chemical engineering 3 QA76 Computer software 3 Biotechnology 2 Conditions and laws of chemical reactions 2 Palm oil 2 Physical and theoretical chemistry 2 Q Science 2 QE Geology 2 QK Botany 2 TK Electrical engineering. Electronics Nuclear engineering 2 Adsorption 1 Analytical chemistry 1 Catalysis 1 Dyes 1 Electrochemical analysis 1 GE Environmental Sciences 1 L Education 1 Medical botany (General) 1 Oils, fats, and waxes 1 QR Microbiology 1 Quantitative analysis 1 R Medicine 1