TK Electrical engineering. Electronics Nuclear engineering 164 Technology: general issues 144 History of engineering and technology 142 Research & information: general 77 human 60 History of engineering & technology 41 Humans 41 Article 37 TJ Mechanical engineering and machinery 34 Power 32 controlled study 31 Solar energy 30 Costs 28 Solar power generation 27 article 27 female 27 male 27 Electric power transmission networks 25 TP Chemical technology 24 Wind power 24 Economic analysis 23 Energy efficiency 23 adult 23 Cost benefit analysis 22 MATLAB 22 Physics 22 Energy utilization 21 Investments 21 Renewable energies 21 Research and information: general 20