Ostrich《鸵鸟》（季刊）. Ostrich: Journal of African Ornithology is the leading ornithological journal in Africa, and publishes peer-reviewed scientific papers and short communications (<2,000 words) on all aspects of ornithology conducted in Africa and its associated islands and marine habitats.

Osteoporosis International《国际骨质疏松症》（月刊）. An international multi-disciplinary journal which is a joint initiative between the International Osteoporosis Foundation and the National Osteoporosis Foundation of the USA, Osteoporosis International provides a forum for the communication and exchange of current ideas concerning the diagnosis, prevention, treatment and management of osteoporosis and other metabolic bone diseases.

Osteoarthritis and Cartilage《骨关节炎与软骨》（月刊）. Osteoarthritis and Cartilage is the official journal of the Osteoarthritis Research Society International. It is an international, multidisciplinary journal that disseminates information for the many kinds of specialists and practitioners concerned with osteoarthritis.

Osaka Journal of Mathematics《大阪数学期刊》（季刊）. Osaka Journal of Mathematics is published quarterly by the joint editorship of the Department of Mathematics, Graduate School of Science, Osaka University, and the Department of Mathematics, Graduate School of Science, Osaka Metropolitan University and the Department of Pure and Applied Mathematics, Graduate School of Information Science and Technology, Osaka University with the cooperation of the Department of Mathematical Sciences, Faculty of Engineering Science, Osaka University. The Journal is devoted entirely to the publication of original works in pure and applied mathematics.

Oryx《羚羊》（双月刊）. Oryx—The International Journal of Conservation is a bimonthly, peer-reviewed, open access journal of biodiversity conservation, conservation policy and sustainable use, and the interaction of these subjects with social, economic and political issues. The journal is interdisciplinary and has a particular interest in material that has the potential to improve conservation management and practice. Oryx supports the publishing and communication aspirations of conservation researchers and practitioners worldwide and helps build capacity for conservation. Besides research Articles and Short Communications, Oryx regularly publishes Reviews, Forum Articles, Book Reviews and Letters, and every issue includes a selection of international conservation news.

Orvosi Hetilap《医学周刊》（周刊）. The journal publishes original and review papers in the fields of experimental and clinical medicine. It covers epidemiology, diagnostics, therapy and the prevention of human diseases as well as papers of medical history. Orvosi Hetilap is the oldest, still in-print, Hungarian publication and also the one-and-only weekly published scientific journal in Hungary.

Orthopedic Clinics of North America《北美矫形临床》（季刊）. Orthopedic Clinics offers clinical review articles on the most cutting-edge technologies and techniques in the field. Published four times a year—in January, April, July, and October—each issue focuses on a single topic that crosses over the following specialty areas: adult reconstruction, upper extremity, pediatrics, trauma, foot and ankle, and sports medicine.

Orthopaedics & Traumatology-Surgery & Research《骨科与创伤学：外科学与研究》（一年8期）. Orthopaedics & Traumatology: Surgery & Research (OTSR) publishes original scientific work in English related to all domains of orthopaedics. Original articles, Reviews, Technical notes and Concise follow-up of a former OTSR study are published in English in electronic form only and indexed in the main international databases.

《中华骨科杂志（英文版）》（Orthopaedic Surgery）（月刊），创刊于2009年，是天津市天津医院与约翰威立国际出版集团合作出版的国内第一本骨科英文SCI期刊。出版高质量骨科原创性学术论文，旨在为骨科同仁提供一个快速展示学术成果的国际化开放获取平台。

Orthopaedic Journal of Sports Medicine《运动医疗骨科杂志》（月刊）. The Orthopaedic Journal of Sports Medicine (OJSM), developed by the American Orthopaedic Society for Sports Medicine (AOSSM), is a global, peer-reviewed, open access journal that combines the interests of researchers and clinical practitioners across orthopaedic sports medicine, arthroscopy, and knee arthroplasty.