Operations research 514 Production and operations management--Product management 291 Operating systems (Computers) 176 Operating systems 161 Project management--PERT/CPM 161 Management 136 Engineering & allied operations 120 Operational calculus-- Functional analysis-- Mathematics 109 Operations Research-- Information management-- Executive management 106 Production management 104 Operations management 100 Production and operations management 85 Operations Research--Information management--Executive management 80 Co-operative management 76 Co operation 67 Computer science 66 Operator theory 61 Economics 59 Linear programming 54 Linear operators 50 Operating system 46 Mathematics 43 Cooperatives 39 History 37 Supply chain management 33 India 29 Travel Management --Travel agency and tour operations managmenet 29 Applied physics 27 Production management--Industrial management 25 Tourism travel--Travel Management --Travel agency and tour operations managmenet 25