| Ketosis |
| Ketosteroids |
| Ketotifen |
| Khellin |
| Ki-67 Antigen |
| Kidd Blood-Group System |
| Kidney |
| Kidney Calculi |
| Kidney Calices |
| Kidney Concentrating Ability |
| Kidney Cortex |
| Kidney Cortex Necrosis |
| Kidney Diseases, Cystic |
| Kidney Failure |
| Kidney Failure, Acute |
| Kidney Failure, Chronic |
| Kidney Glomerulus |
| Kidney Medulla |
| Kidney Neoplasms |
| Kidney Papillary Necrosis |
| Kidney Pelvis |
| Kidney Transplantation |
| Kidney Tubular Necrosis, Acute |
| Kidney Tubules, Collecting |
| Kidney Tubules, Distal |
| Kidney Tubules, Proximal |
| Kidney, Artificial |
| Killer Cells |
| Killer Cells, Lymphokine-Activated |
| Killer Cells, Natural |
| Killifishes |
| Kindling (Neurology) |
| Kinesics |
| Kinesin |
| Kinesiology, Applied |
| Kinesis |
| Kinesthesis |
| Kinetics |
| Kinetin |
| Kinetocardiography |
| Kinetochores |
| Kinetofragminophorea |
| Kinetoplastida |
| King's Evil |
| Kingella |
| Kingella kingae |
| Kininogen, High-Molecular-Weight |
| Kininogen, Low-Molecular-Weight |
| Kininogens |
| Kinins |
| Kirsten murine sarcoma virus |
| Kitasamycin |
| Klatskin's Tumor |
| Klebsiella |
| Klebsiella Infections |
| Klebsiella oxytoca |
| Klebsiella pneumoniae |
| Kleine-Levin Syndrome |
| Klinefelter Syndrome |
| Klippel-Feil Syndrome |
| Klippel-Trenaunay-Weber Syndrome |
| Kluver-Bucy Syndrome |
| Kluyvera |
| Kluyveromyces |
| Knee Dislocation |
| Knee Injuries |
| Knee Prosthesis |
| Knowledge |
| Knowledge Bases |
| Knowledge of Results (Psychology) |
| Korarchaeota |
| Korean War |
| Koro |
| Korsakoff Syndrome |
| Krameriaceae |
| Kringles |
| Krukenberg Tumor |
| Kruppel-Like Transcription Factors |
| Krypton |
| Krypton Radioisotopes |
| Kunzea |
| Kupffer Cells |
| Kuru |
| Kv Channel-Interacting Proteins |
| Kv1.1 Potassium Channel |
| Kv1.2 Potassium Channel |
| Kv1.3 Potassium Channel |
| Kv1.4 Potassium Channel |
| Kv1.5 Potassium Channel |
| Kv1.6 Potassium Channel |