Chemical engineering 10 Chemical elements 8 Extraction (Chemistry) 6 Physical and theoretical chemistry 6 Analytical chemistry 5 TP Chemical technology 5 Chemicals 4 Oils, fats, and waxes 4 Organic chemistry 4 Adsorption 3 Special processes and operations 3 Biotechnology 2 Botanical chemistry. Phytochemicals 2 Electrolytes, electrolyte solutions 2 Enviromental management 2 Laboratories. General works 2 Miscellaneous organic chemical industries 2 QD Chemistry 2 TJ Mechanical engineering and machinery 2 Acids 1 Acids and bases 1 Agricultural conservation 1 Air pollution and its control 1 Algorithms 1 Bacteria 1 Biomass 1 Catalysis 1 Catfishes 1 Chitosan 1 Collagen 1