| Micronesia |
| Micronuclei, Chromosome-Defective |
| Micronucleus Tests |
| Micronucleus, Germline |
| Micronutrients |
| Microphthalmia-Associated Transcription Factor |
| Microphthalmos |
| Microradiography |
| MicroRNAs |
| Microsatellite Repeats |
| Microscopic Angioscopy |
| Microscopy |
| Microscopy, Acoustic |
| Microscopy, Atomic Force |
| Microscopy, Confocal |
| Microscopy, Electron |
| Microscopy, Electron, Scanning |
| Microscopy, Electron, Scanning Transmission |
| Microscopy, Electron, Transmission |
| Microscopy, Energy-Filtering Transmission Electron |
| Microscopy, Fluorescence |
| Microscopy, Fluorescence, Multiphoton |
| Microscopy, Immunoelectron |
| Microscopy, Interference |
| Microscopy, Phase-Contrast |
| Microscopy, Polarization |
| Microscopy, Scanning Probe |
| Microscopy, Scanning Tunneling |
| Microscopy, Ultraviolet |
| Microscopy, Video |
| Microsomes |
| Microsomes, Liver |
| Microspectrophotometry |
| Microspheres |
| Microsporea |
| Microsporida |
| Microsporidia |
| Microsporidia, Unclassified |
| Microsporidiosis |
| Microsporum |
| Microstomia |
| Microsurgery |
| Microtomy |
| Microtubule Proteins |
| Microtubule-Associated Proteins |
| Microtubule-Organizing Center |
| Microtubules |
| Microvascular Angina |
| Microvilli |
| Microviridae |
| Microvirus |
| Microwaves |
| Mid-Atlantic Region |
| Midazolam |
| Middle Cerebral Artery |
| Middle Ear Ventilation |
| Middle East |
| Middle Lobe Syndrome |
| Midline Thalamic Nuclei |
| Midodrine |
| Midwestern United States |
| Midwifery |
| Mifepristone |
| Migraine Disorders |
| Migraine with Aura |
| Migraine without Aura |
| Mikamycin |
| Mikania |
| Mikulicz' Disease |
| Miliaria |
| Milieu Therapy |
| Military Dentistry |
| Military Medicine |
| Military Nursing |
| Military Personnel |
| Military Psychiatry |
| Milk |
| Milk Banks |
| Milk Ejection |
| Milk Hypersensitivity |
| Milk Proteins |
| Milk Sickness |
| Milk Substitutes |
| Milk Thistle |
| Miller Fisher Syndrome |
| Millettia |
| Milrinone |
| Mimosa |
| Mimosine |
| Mimulus |