| Nyelv- Es Irodalomtudományi Közlemények | | 0567-6223 |
| Nyelvtudomány (acta Universitatis Szegediensis Sectio Linguistica) | | 1786-7428 |
| Nyelvtudományi Közlemények | | 0029-6791 |
| Nytt Om Runer | | 0801-3756 |
| O.p.d. Restauro. Rivista Dell'opificio Delle Pietre Dure E Laboratori di Restauro di Firenze | | 1120-2513 |
| Oase | OASE | 0169-6238 |
| OASIS-Observatorio de Analisis de los Sistemas Internacionales | OASIS-OBSERVATORIO DE ANALISIS DE LOS SISTEMAS INTERNACIONALES | 1657-7558 |
| Obere Extremitaet-Schulter-Ellenbogen-Hand-Upper Extremity-Shoulder Elbow Hand | OBERE EXTREMITAET-SCHULTER-ELLENBOGEN-HAND-UPPER EXTREMITY-SHOULDER ELBOW HAND | 1862-6599 |
| Obesity | OBESITY | 1930-7381 |
| Obesity and Metabolism | OBESITY AND METABOLISM | 2071-8713 |
| Obesity and Metabolism-milan | OBES METAB-MILAN | 1825-3865 |
| Obesity Facts | OBESITY FACTS | 1662-4025 |
| Obesity Medicine | OBESITY MEDICINE | 2451-8476 |
| Obesity Research | OBES RES | 1071-7323 |
| Obesity Research | | |
| Obesity Research & Clinical Practice | OBES RES CLIN PRACT | 1871-403X |
| Obesity Reviews | OBES REV | 1467-7881 |
| Obesity Science & Practice | OBESITY SCIENCE & PRACTICE | 2055-2238 |
| Obesity Surgery | OBES SURG | 0960-8923 |
| OBETS-Revista de Ciencias Sociales | OBETS-REVISTA DE CIENCIAS SOCIALES | 1989-1385 |
| Oblicza Komunikacji | | 2083-5345 |
| Obnovljeni Zivot | | 0351-3947 |
| Obogashchenie Rud | OBOGASHCHENIE RUD | 0202-3776 |
| Obra Digital-Revista de Comunicacion | OBRA DIGITAL-REVISTA DE COMUNICACION | 2014-5039 |
| Obrabotka Metallov-Metal Working and Material Science | OBRABOTKA METALLOV-METAL WORKING AND MATERIAL SCIENCE | 1994-6309 |
| Obradoiro de Historia Moderna | | 1133-0481 |
| Obrana a strategie | | 1214-6463 |
| Obrazovanie i Nauka | OBRAZOVANIE I NAUKA | 1994-5639 |
| Obróbka Plastyczna Metali | | 0867-2628 |
| Observar | OBSERVAR | 1988-5105 |
| Observatorio | OBSERVATORIO | 0874-8810 |
| Observatorio Medioambiental | OBSERVATORIO MEDIOAMBIENTAL | 1139-1987 |
| Observatory | OBSERVATORY | 0029-7704 |
| Obshchaya Reanimatologiya | OBSHCHAYA REANIMATOLOGIYA | 1813-9779 |
| Obsidian Iii: Literature in the African Diaspora | | 1542-1619 |
| Obstetric Medicine | OBSTETRIC MEDICINE | 1753-495X |
| Obstetrica si Ginecologie | OBSTETRICA SI GINECOLOGIE | 1220-5532 |
| Obstetrical and Gynecological Survey | OBSTET GYNECOL SURV | 0029-7828 |
| Obstetrician & Gynaecologist | OBSTETRICIAN & GYNAECOLOGIST | 1467-2561 |
| Obstetrics and Gynaecology Forum | OBSTETRICS AND GYNAECOLOGY FORUM | 1029-1962 |
| Obstetrics and Gynecology | OBSTET GYNECOL | 0029-7844 |
| Obstetrics and Gynecology Clinics of North America | OBSTET GYN CLIN N AM | 0889-8545 |
| Obstetrics and Gynecology International | OBSTETRICS AND GYNECOLOGY INTERNATIONAL | 1687-9589 |
| Obstetrics and Gynecology Science | OBSTETRICS AND GYNECOLOGY SCIENCE | 2287-8572 |
| Obstetrics, Gynaecology and Reproductive Medicine | OBSTETRICS, GYNAECOLOGY AND REPRODUCTIVE MEDICINE | 1751-7214 |
| Obstetrics, Gynecology and Reproduction | OBSTETRICS, GYNECOLOGY AND REPRODUCTION | 2313-7347 |
| Occasional Papers on Religion in Eastern Europe | OCCASIONAL PAPERS ON RELIGION IN EASTERN EUROPE | 1069-4781 |
| Occupational and Environmental Medicine | OCCUP ENVIRON MED | 1351-0711 |
| Occupational Ergonomics | OCCUPATIONAL ERGONOMICS | 1359-9364 |
| Occupational health & safety (Waco, Tex.) | OCCUPATIONAL HEALTH & SAFETY (WACO, TEX.) | 0362-4064 |
