TK Electrical engineering. Electronics Nuclear engineering 200 TJ Mechanical engineering and machinery 25 QC Physics 23 HE Transportation and Communications 15 QA75 Electronic computers. Computer science 14 TP Chemical technology 9 Q Science (General) 6 TA Engineering (General). Civil engineering (General) 6 TL Motor vehicles. Aeronautics. Astronautics 6 T Technology (General) 5 TK5101-6720 Telecommunication 4 TK6570 Mobile Communication System 4 QA76 Computer software 3 QH301 Biology 3 R Medicine (General) 3 NA Architecture 2 TK7885-7895 Computer engineer. Computer hardware 2 Unspecified 2 G109.5 Global Positioning System 1 Geoinformation and Real Estate 1 HD Industries. Land use. Labor 1 HD1394-1394.5 Real estate management 1 HG Finance 1 QA Mathematics 1 S Agriculture (General) 1 T58.5-58.64 Information technology 1 TC Hydraulic engineering. Ocean engineering 1 TE Highway engineering. Roads and pavements 1 TK5015.888 Web sites 1 TN Mining engineering. Metallurgy 1