3369416 RCTs randomized controlled trials 59357 1526299 RCT randomized controlled trial 19414 3355683 RCT's randomized clinical trials 8 3369550 RCTS randomized clinical trials 7 3408767 RTCs randomized clinical trials 7 1565713 RTC randomized clinical trials 2 3861911 RRCTs randomized clinical trials 1