Soviet Union 282 History 243 Foreign relations 127 Politics and government 111 Folklore 81 Folk songs 77 Music 67 Social Sciences 57 Social conditions 55 Education 54 Arts 53 Economics 49 Agriculture 47 India 47 Psychology 45 Songs 45 United States 45 Philosophy 44 UNIX 44 Finance 43 Biography 42 Communication 42 Folk Songs 42 China 39 Industries 39 Population 39 Research 39 Non-governmental organizations 37 Rural development 37 Transportation 37