| PIF | paratoid isoelectric focusing variant protein; peak inspiratory flow; proinsulin-free; prolactin-inh... |
|---|---|
| PRIH | prolactin release-inhibiting hormone |
| 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... |