History 273 History and criticism 102 Politics and government 70 Social conditions 48 English literature 35 Criticism and interpretation 30 Mathematical models 26 Mathematics 26 Social aspects 26 Fishing - methods, gear, equipments, apparatus, materials 23 Foreign relations 23 Philosophy 23 Agricultural engineering 21 Economic conditions 21 Intellectual life 21 Agroecological requirements 20 Law and legislation 20 Women 20 Equipment and supplies 19 Agriculture 18 Nutrition 18 Data processing 17 Church history 16 Research 16 Computer networks 15 Image processing 15 Nutrient requirements 15 Political aspects 15 World War, 1939-1945 15 Agronomy 14