- Obesity 1208 studies
- Obesity Hypoventilation Syndrome 2 studies
- Obesity, Morbid 64 studies
- Obsessive Behavior 1 study
- Obsessive-Compulsive Disorder 91 studies
- Obstetric Labor Complications 159 studies
- Obstetric Labor, Premature 122 studies
- Occupational Diseases 29 studies
- Ochronosis 2 studies
- Ocular cicatricial pemphigoid 1 study
- Ocular Hypertension 302 studies
- Ocular melanoma 20 studies
- Ocular Motility Disorders 42 studies
- Oculocerebrorenal Syndrome 2 studies
- Oculocutaneous tyrosinemia 2 studies
- Oculopharyngeal muscular dystrophy 1 study
- Olfaction Disorders 2 studies
- Oligodendroglioma 248 studies
- Oligomenorrhea 1 study
- Oligospermia 4 studies
- Oliguria 1 study
- Omenn syndrome 1 study
- Onchocerciasis 3 studies
- Oncogenic osteomalacia 1 study
- Onycholysis 1 study
- Onychomycosis 21 studies
- Ophthalmia Neonatorum 1 study
- Opioid-Related Disorders 218 studies
- Opitz syndrome 9 studies
- Opportunistic Infections 174 studies
- Oppositional defiant disorder 16 studies
- Opsoclonus-Myoclonus Syndrome 3 studies
- Optic Atrophies, Hereditary 4 studies
- Optic Atrophy 4 studies
- Optic Atrophy, Hereditary, Leber 1 study
- Optic Nerve Diseases 30 studies
- Optic nerve disorder 30 studies
- Optic Neuritis 14 studies
- Optic neuropathy, anterior ischemic 7 studies
- Optic Neuropathy, Ischemic 8 studies
- Oral cancer 111 studies
- Oral facial digital syndrome 1 study
- Oral facial dyskinesia 15 studies
- Oral leukoplakia 11 studies
- Oral lichen planus 10 studies
- Oral Manifestations 3 studies
- Oral squamous cell carcinoma 4 studies
- Oral Ulcer 8 studies
- Orbital Diseases 20 studies
- Orbital Fractures 2 studies
- Orbital lymphoma 1 study
- Ornithine aminotransferase deficiency 2 studies
- Ornithine Carbamoyltransferase Deficiency Disease 5 studies
- Ornithine Transcarbamylase Deficiency 5 studies
- Orofaciodigital Syndromes 1 study
- Oropharyngeal cancer, adult 3 studies
- Oropharyngeal Neoplasms 22 studies
- Orthomyxoviridae Infections 378 studies
- Orthostatic intolerance 16 studies
- Ossification, Heterotopic 2 studies
- Osteitis 12 studies
- Osteitis Deformans 18 studies
- Osteoarthritis 560 studies
- Osteoarthritis, Hip 61 studies
- Osteoarthritis, Knee 236 studies
- Osteochondrodysplasias 35 studies
- Osteochondromatosis 3 studies
- Osteogenesis Imperfecta 13 studies
- Osteogenic sarcoma 175 studies
- Osteolysis 2 studies
- Osteomalacia 5 studies
- Osteomyelitis 11 studies
- Osteonecrosis 47 studies
- Osteopetrosis 6 studies
- Osteoporosis 503 studies
- Osteoporosis, Postmenopausal 106 studies
- Osteoradionecrosis 2 studies
- Osteosarcoma 175 studies
- Otitis 66 studies
- Otitis Externa 1 study
- Otitis Media 59 studies
- Otitis Media with Effusion 15 studies
- Otitis Media, Suppurative 2 studies
- Otorhinolaryngologic Diseases 699 studies
- Otorhinolaryngologic Neoplasms 100 studies
- Otosclerosis 2 studies
- Ovarian cancer 774 studies
- Ovarian carcinosarcoma 11 studies
- Ovarian Cysts 88 studies
- Ovarian Diseases 873 studies
- Ovarian dwarfism 29 studies
- Ovarian epithelial cancer 491 studies
- Ovarian Failure, Premature 21 studies
- Ovarian Hyperstimulation Syndrome 10 studies
- Ovarian low malignant potential tumor 2 studies
- Ovarian Neoplasms 774 studies
- Overdose 3 studies
- Overnutrition 992 studies
- Overweight 1082 studies
- Oxalosis 6 studies
Clinical Trials Authorship and Review
Clinical Trials content is provided directly by the U.S. National Institutes of Health via ClinicalTrials.gov and is not reviewed separately by ClinicalTrialsFeeds.org. Every page of specific clinical trials information contains a unique identifier which can be used to find further details directly from the National Institutes of Health.
