| IR | drop of voltage across a resistor produced by a current; ileal resection; immune response; immunizat... |
|---|---|
| ORS | olfactory reference syndrome; oral rehydration solution; oral surgery, oral surgeon; Orthopaedic Res... |
| ER | efficiency ratio; epigastric region; ejection rate; electroresection; emergency room; endoplasmic re... |
| SR | sarcoplasmic reticulum; saturation recovery; scanning radiometer; screen; secretion rate; sedimentat... |
| OCP | octacalcium phosphate; ocular cicatricial pemphigoid; oral case presentation; oral contraceptive pil... |