History 172 Dissertations, Academic (Ph.D) 80 History and criticism 59 Economics 57 General management 50 Oceanography 36 English literature 35 atmosphere 35 Climatology 34 Dissertations, Academic(Ph.D) 34 Mathematics 34 Philosophy 34 Business communication 33 Criticism 31 India 31 Agriculture 30 Management 30 Biochemistry 26 Fish physiology-- Physiology of fishes 26 Quantum mechanics; Physics 26 Taxonomy of animals in ancient India-- British India 25 Microbiology, microorganisms 24 Religion 24 Agronomy 22 Malayalam literature 22 Politics and government 22 Arts 21 Criticism and interpretation 21 Analytic chemistry 20 Biography 20