History 1,690 Nationalism 867 Politics and government 753 National security 350 Foreign relations 285 Social aspects 279 National socialism 275 History and criticism 247 Social conditions 234 Political aspects 223 Civilization 163 Economic conditions 152 Ethnic relations 117 Study and teaching 114 Government policy 108 Education 102 Historiography 100 Research 99 World War, 1939-1945 99 Social life and customs 96 Economic aspects 93 Ethnicity 91 Exhibitions 86 Group identity 86 Security, International 86 International relations 82 English literature 81 Emigration and immigration 76 World politics 75 Economic policy 74