Effects of Qingda granule on patients with grade 1 hypertension at low-medium risk: study protocol for a randomized, controlled, double-blind clinical trial. - Long, Lin-zi; Chu, Jian-feng; Qu, Hua; Yang, Qiao-ning; Lu, Yan; Fu, Chang-geng; Peng, Jun; Chen, Ke-ji (Trials, 2023)