| RF | radial fiber; radio frequency; receptive field; regurgitant fraction; Reitland-Franklin [unit]; rela... |
|---|---|
| RI | radiation intensity; radioactive isotope; radioimmunology; recession index; recombinant inbred [stra... |
| RIF | radiological interface; release-inhibiting factor; rifampin; right iliac fossa; rosette-inhibiting f... |
| RR | radiation reaction; radiation response; rate ratio; rational recovery [group]; recovery room; relati... |
| RRR | regular rhythm and rate; renin release rate (or ratio) |