Research 2,756 Religión 1,074 Religion 930 Relaciones internacionales 481 Religious aspects 369 Relations 301 Recursos hd̕ricos 281 Recursos naturales 256 Residuos 214 Residuos industriales 211 Reacciones qum̕icas 206 Risk management 203 Rural conditions 199 Regional planning 168 Renewable energy sources 152 Recursos humanos 151 Rehabilitation 142 Rural development 139 Reading 137 Residuos sl̤idos 122 Relaciones exteriores 118 Research and methodology 116 Recubrimientos 111 Recycling 111 Redes sociales 111 Recherche 106 Reciclaje 103 Referencia 102 Remote sensing 102 Reference 100 Renewable energies 93 Real property 91 Refugees 86 Residuos peligrosos 86 Roman law 85 Robotics 78 Religions 77 Rhetoric 77 Race relations 75 Recubrimientos metl̀icos 74 Recycling industry 72 Religiones 71 Representative government and representation 71 Religious life and customs 70 Recursos energťicos renovables 69 RELIGION Y CIENCIA 68 Radio 68 Responsabilidad social 66 Retail trade 65 Reactores qum̕icos 63 Residuos - Aspectos ambientales 63 Regionalism 61 Resistencia de materiales 61 Respiratory organs 61 Reading comprehension 60 Relaciones públicas 60 Revolutions 60 Russian literature 60 Railroads 59 Refuse and refuse disposal 59 RIEGO 56 Religious life 56 Responsabilidad por el medio ambiente 56 Robots 55 Relaciones económicas internacionales 52 Religion & Philosophy (General) 52 Relaciones laborales 51 Right and left (Political science) 51 Recreation 50 Relaciones 50 Responsabilidad social de los negocios 50 RETORICA 48 Real estate business 48 Redes informáticas 47 Religion and politics 47 Responsabilidad social empresarial 47 Relaciones interpersonales 46 Restaurant management 45 Riesgo 45 Romanticism 45 Racism 44 Recubrimientos no metl̀icos 44 Rehabilitación 44 Reproduction 44 Residuos industriales - Aspectos ambientales 43 Rites and ceremonies 43 Relaciones gubernamentales 42 Religion and sociology 42 Religion and science 41 Risk 41 Republicanism 39 RELIGION 38 Race discrimination 38 Radio broadcasting 38 Risk assessment 38 Resilience (Personality trait) 37 Responsabilidad 37 Reviews 36 Radiography 35 Recycling (Waste, etc.) 35