History 54 Dissertations, Academic (Ph.D) 51 Microbiology 32 Biography 31 Literature 24 Social Sciences 21 History and criticism 19 Economics 18 Biotechnology 17 Boys 17 Woody plants 17 Criticism and interpretation 16 methods 16 Education 15 Forestry 15 Isolation 15 Plants 15 Wood 15 English literature 14 India 14 Novel 14 Politics and government 14 isolation & purification 14 Andy Davies 13 Bob Lewis 13 Bob Wilson 13 Feminism 13 Fiction 13 Fred Fawbert 13 Gerard O`Neil 13