Religious aspects 227,207 Research 199,948 Religion 154,642 Relations 123,976 Railroads 84,145 Roads 65,593 Race relations 58,274 Religious life 45,919 Russian literature 40,996 Regional planning 40,819 Russian language 35,304 Rural conditions 34,926 Real property 34,484 Rock music 33,775 Religious life and customs 32,820 Reference 32,055 Rhetoric 30,898 Refugees 30,786 Rural development 29,017 Rites and ceremonies 28,210 Rules and practice 24,859 Regimental histories 24,211 Rehabilitation 24,016 Reformation 21,971 Racism 20,826 Readers 20,327 RELIGION 20,247 Reading 19,846 Revolutionaries 18,767 Radio 16,703 Russian poetry 15,432 Roman law 14,944 Religions 14,762 Russian 14,674 Rabbis 14,631 Romanticism 14,343 Responsa 14,181 Rivers 13,910 Rare books 13,889 Representative government and representation 13,860 Renaissance 13,735 Religion and science 13,637 Revolutions 13,559 Rituals 13,191 Relations extérieures 12,700 Registers of births, etc 12,563 Retirement 11,920 Renewable energy sources 11,514 Radicalism 11,331 Rates 11,186 Religion and politics 11,087 Reorganization 11,005 Russians 10,997 Remote sensing 10,895 Retail trade 10,838 Registration and transfer 10,798 Recherche 10,422 Rap (Music) 10,328 Romans 10,309 Risk management 10,061 Refuse and refuse disposal 9,873 Reproduction 9,531 Religious education 9,361 Registers 9,336 Regionalism 9,185 Revenue 9,064 Reformed Church 9,060 Radio broadcasting 9,013 Race discrimination 9,000 Riots 8,934 Religion and state 8,923 Recreation 8,800 Radiation 8,695 Robotics 8,456 Reconstruction (1939-1951) 8,371 Rock musicians 8,323 Risk assessment 8,271 Religion and sociology 8,015 Race identity 7,858 Restaurants 7,844 Recruiting, enlistment, etc 7,834 Repentance 7,432 Romanies 7,427 Reclamation of land 7,231 Requiems 7,214 Right and left (Political science) 7,145 Radiography 7,052 Research, Industrial 6,812 Revenge 6,718 Rice 6,624 Russian fiction 6,448 Rule of law 6,419 Romances 6,225 Real estate business 6,170 Relations with women 6,118 Rating of 5,955 Reconstruction (U.S. history, 1865-1877) 5,887 Recruiting 5,838 Race 5,835 Reform 5,742