| 345 | Ottawa Civic Hospital |  | 2352 | 1220 | 1376 | 144 |
| 5059 | Otorhinolaryngology Clinical Research Center / Научно клинический центр оториноларингологии ФМБА |  | 2775 | 3608 | 2538 | 3879 |
| 5357 | Ostschweizer Kinderspital |  | 5892 | 3803 | 2538 | 3879 |
| 976 | Osterreichisches Institut für Wirtschaftsforschung |  | 1055 | 1123 | 1250 | 2124 |
| 5094 | Österreichisches Institut für Menschenrechte | | 3319 | 3634 | 2538 | 3879 |
| 5372 | Osterreichische Institut für Internationale Politik | | 2406 | 4144 | 2538 | 3879 |
| 4404 | Osterreichische Forschungsstiftung für Entwicklungshilfe | | 3175 | 2591 | 2538 | 3879 |
| 61 | Osterreichische Akademie der Wissenschaften | | 35 | 181 | 120 | 125 |
| 5503 | Ost-West Wissenschaftszentrum |  | 5040 | 4111 | 2538 | 3879 |
| 2556 | Osservatorio Astronomico Roma |  | 4692 | 6688 | 2538 | 543 |
| 7295 | Osservatorio Astronomico di Trieste | | 2084 | 7042 | 2538 | 3879 |
| 4542 | Osservatorio Astronomico di Torino | | 5160 | 6668 | 2538 | 2510 |
| 2594 | Osservatorio Astronomico di Capodimonte | | 4011 | 7225 | 1922 | 1001 |
| 6350 | Osservatorio Astronomico di Bologna | | 2636 | 5535 | 2538 | 3879 |
| 7536 | Osservatorio Astrofisico di Catania | | 4688 | 7266 | 2538 | 3879 |
| 4346 | Osservatorio Astrofisico di Arcetri | | 2178 | 5256 | 869 | 3879 |
| 206 | Ospedale San Raffaele (Istituto Scientifico Universitario) | | 2280 | 1166 | 37 | 116 |
| 613 | Ospedale Pediatrico Gaslini | | 3303 | 2372 | 209 | 519 |
| 494 | Ospedale Niguarda | | 786 | 1770 | 333 | 458 |
| 405 | Ospedale Maggiore Policlinico Milano | | 1330 | 1924 | 506 | 176 |
| 6255 | Ospedale Gradenigo | | 4961 | 5240 | 2538 | 3879 |
| 8130 | Ospedale Giovanni Fornaroli | | 8091 | 8125 | 2538 | 3879 |
| 4195 | Ospedale di Circolo Fondazione Macchi | | 4870 | 6471 | 2538 | 2377 |
| 4116 | Oslo University Hospital Research |  | 1004 | 2335 | 2538 | 3879 |
| 476 | Oslo Universitetssykehus | | 1633 | 1168 | 2538 | 76 |
| 7781 | Oslo Heart Center | | 8011 | 7337 | 2538 | 3879 |
| 4319 | Osiris Therapeutics |  | 3743 | 2436 | 2538 | 3879 |
| 2524 | OSF Saint Francis Medical Center | | 894 | 954 | 2258 | 3879 |
| 7242 | Oscar G. Johnson VA Medical Center | | 6295 | 7315 | 2538 | 3660 |
| 4596 | Osaka Rosai Hospital |  | 4338 | 7314 | 2538 | 2077 |
| 4864 | Osaka Prefectural Institute of Public Health | | 3259 | 6990 | 2538 | 2627 |
| 1532 | Osaka National Hospital | | 3631 | 2190 | 2538 | 1351 |
| 3503 | Osaka Municipal Technical Research Institute | | 4680 | 4741 | 2538 | 2733 |
| 3553 | Orthopedic Institute Gaetano Pini | | 2710 | 4895 | 2521 | 2867 |
| 7122 | Orthopaedic Research of Virginia | | 5884 | 6526 | 2538 | 3879 |
| 6686 | Orthopädische Klinik Volmarstein | | 6360 | 5801 | 2538 | 3879 |
| 7235 | Orlando Clinical Research Center | | 7368 | 6589 | 2538 | 3879 |
| 7437 | Oriental Institute ASCR |  | 3092 | 7185 | 2538 | 3879 |
| 6149 | Orient Institute | | 6872 | 4884 | 2538 | 3879 |
| 2764 | Organization for Tropical Studies |  | 2870 | 1930 | 2538 | 3252 |
| 1739 | Organización Nacional de Trasplantes |  | 1801 | 1097 | 2538 | 2653 |
| 1555 | Organización Europea para la Investigación Astronómica en el Hemisferio Austral ESO |  | 6510 | 3566 | 2538 | 596 |
| 88 | Organisation for Economic Co-operation and Development | | 125 | 9 | 410 | 1210 |
| 1956 | Organic and Physical Chemistry Institute A E Arbuzov Kazan Scientific Center RAS / Институт органической и физической химии им А Е Арбузова Казанского научного центра РАН | | 3736 | 4722 | 1728 | 1873 |
| 6930 | Orentreich Foundation for Advancement of Science | | 6922 | 6151 | 2538 | 3879 |
| 7376 | Orenburg Scientific Center UB RAS / Оренбургский научный центр Уральского отделения РАН | | 7470 | 6811 | 2538 | 3879 |
| 1624 | Oregon Social Learning Centre | | 4795 | 3258 | 1957 | 1891 |
| 746 | Oregon Research Institute | | 4596 | 1337 | 346 | 1380 |
| 3110 | Oregon Institute of Science and Medicine | | 6107 | 741 | 2538 | 3879 |
| 4142 | Oregon College of Oriental Medicine | | 4017 | 2300 | 2521 | 3879 |
| 4351 | Oregon Clinic | | 4304 | 2446 | 2538 | 3879 |
| 939 | Onze Lieve Vrouw Hospital |  | 2588 | 1519 | 1403 | 1545 |
| 4545 | Ontario Research Center for Computer Algebra | | 5048 | 2688 | 2538 | 3879 |
| 7624 | Ontario Hydro Energy | | 8091 | 6958 | 2538 | 3879 |
| 6790 | Ontar Corporation | | 7725 | 5743 | 2538 | 3879 |
| 6771 | Onkologischer Schwerpunkt Stuttgart | | 7086 | 5838 | 2538 | 3879 |
| 5711 | OncoSalud |  | 5830 | 4349 | 2538 | 3879 |
| 2453 | Onassis Cardiac Surgery Center |  | 5736 | 3767 | 2538 | 1992 |
| 5225 | Omsk Scientific Center SB RAS / Омский научный центр Сибирского отделения РАН | | 3381 | 4886 | 2380 | 3879 |
| 5270 | Omsk Institute of Instrument Engineering / Омский научно исследовательский институт приборостроения | | 3285 | 3865 | 2538 | 3879 |
| 5111 | Omega-3 Research Institute | | 7945 | 2904 | 2538 | 3879 |
| 5161 | Oman Studies Centre |  | 7518 | 3294 | 2538 | 3879 |
| 4459 | Olympic Park Sports Medicine Centre |  | 6123 | 4697 | 2538 | 3316 |
| 4466 | Olivia Newton John Cancer Research Institute | | 6011 | 2488 | 2538 | 3879 |
| 4825 | Olive View UCLA Medical Center | | 6277 | 5506 | 2538 | 3252 |
| 6304 | Olin Neuropsychiatry Research Center | | 7137 | 5079 | 2538 | 3879 |
| 1248 | Oldenburger Forschungs- und Entwicklungsinstitut für Informatik-Werkzeuge und -Systeme | | 2227 | 1204 | 1231 | 2627 |
| 5523 | Old Church Slavonic Institute |  | 5230 | 5547 | 2501 | 3660 |
| 5985 | Ökumenisches Hainich Klinikum | | 5520 | 4762 | 2538 | 3879 |
| 5776 | Oklahoma State University Medical Center | | 6695 | 4355 | 2538 | 3879 |
| 685 | Oklahoma Medical Research Foundation | | 2917 | 1694 | 607 | 865 |
| 4734 | Oklahoma Blood Institute | | 6351 | 2880 | 2538 | 3879 |
| 354 | Okinawa Industrial Technology Center | | 569 | 648 | 221 | 817 |
| 7899 | Okazaki Research Facilities | | 6401 | 7835 | 2538 | 3879 |
| 5504 | Okayama Kyokuto Hospital | | 6351 | 3957 | 2538 | 3879 |
| 5711 | Oil and Gas Problems Institute RAS / Институт проблем нефти и газа РАН | | 4847 | 4434 | 2538 | 3879 |
| 4011 | Oil and Gas Institute in Cracow |  | 2103 | 3522 | 2132 | 3879 |
| 3295 | Ohio Supercomputer Center | | 2823 | 1052 | 2538 | 3879 |
| 2633 | Ohio Aerospace Institute | | 6129 | 3105 | 2538 | 2510 |
| 4937 | Ogden Clinic | | 5040 | 3284 | 2538 | 3879 |
| 2430 | Oficina Española de Patentes y Marcas | | 86 | 481 | 2538 | 3879 |
| 5077 | Office of Public Health and Environmental Hazards | | 5431 | 3441 | 2538 | 3879 |
| 3353 | Office of Naval Research | | 2182 | 2970 | 2538 | 3316 |
| 2011 | Office National de la Chasse et de la Faune Sauvage |  | 1885 | 971 | 1781 | 3660 |
| 5238 | Office National d'Etudes et de Recherches Aérospatiales ONERA Toulouse | | 8091 | 2861 | 2538 | 3879 |
| 347 | Office National d'Etudes et de Recherches Aérospatiales ONERA | | 912 | 789 | 313 | 587 |
| 5527 | Oestfold Research Foundation | | 4309 | 4196 | 2538 | 3879 |
| 741 | Odense University Hospital |  | 1301 | 1654 | 2538 | 166 |
| 4565 | Ocular Immunology and Uveitus Foundation | | 5188 | 2710 | 2538 | 3879 |
| 4325 | Oceanographic Research Institute South African Association for Marine Biological Research |  | 5115 | 4579 | 2538 | 3316 |
| 5188 | Oceanic Institute | | 7271 | 3367 | 2538 | 3879 |
| 7186 | Ocala Heart and Vascular Institute | | 7553 | 6471 | 2538 | 3879 |
| 7571 | Observatorio Tecnológico Textil-Confección | | 7318 | 7176 | 2538 | 3879 |
| 7188 | Observatorio San Calixto |  | 6092 | 6636 | 2538 | 3879 |
| 619 | Observatório Nacional |  | 3008 | 1066 | 693 | 1136 |
| 5629 | Observatorio de Prospectiva Tecnológica Industrial | | 6556 | 4143 | 2538 | 3879 |
| 4937 | Observatorio Colombiano de Ciencia y Tecnología |  | 3600 | 4173 | 2469 | 3879 |
| 5516 | Observatorio Astronómico de Mallorca | | 8091 | 3236 | 2538 | 3879 |
| 1883 | Observatoire Océanologique de Banyuls-sur-Mer | | 1449 | 2018 | 889 | 3316 |
| 99 | Observatoire de Paris | | 383 | 158 | 266 | 166 |
