| RI | radiation intensity; radioactive isotope; radioimmunology; recession index; recombinant inbred [stra... |
|---|---|
| RRE, RR&E | round, regular, and equal [pupils] |
| RRR | regular rhythm and rate; renin release rate (or ratio) |
| RR&R | regular rate and rhythm |
| RSA | rabbit serum albumin; regular spiking activity; relative specific activity; relative standard accura... |