Peace 117 History 114 Dissertations, Academic (Ph.D) 93 Semiconductors 87 Optoelectronic devices 80 Philosophy 69 Economics 60 Thesis (Ph.D)-Education 55 Nanotechnology 53 Agronomy 51 Education 47 Management 47 Research 46 Human rights 42 History and criticism 41 Women 40 Electronics 39 Engineering 39 Physics 39 Agricultural Extension 38 Mass media 38 English literature 36 Politics and government 36 Psychology 36 Religion 36 Social aspects 36 War 34 Electronic circuits 33 India 33 Law and legislation 33