History 114 Dissertations, Academic (Ph.D) 53 Philosophy 44 History and criticism 36 Aves (Birds) 32 Social conditions 29 Law and legislation 28 Aged 27 Women 27 English literature 25 Literature 25 English poetry 24 Research 24 Biological control agents 23 Natural enemies 23 Local area networks (Computer networks) 22 methods 22 Biological Control 21 Mass media 21 Microbiology 21 Aves 20 Biological control 20 Politics and government 20 Underdeveloped areas 19 Criticism and interpretation 18 Economics 18 Globalization 18 Social aspects 17 Antineoplastic agents 16 Biotechnology 16