Most devastatingly, however, there are no randomized, double-blinded placebo controlled clinical trials that compare the success of quitting smoking by using smokeless tobacco versus using a placebo.

然而，极具讽刺的是，通过使用无烟烟草戒烟与使用安慰对照组相比，临床对照控制组没有进行随机的双盲试验。

youdao

Trials were included if they were randomized, double-blinded, and controlled with placebo or active comparator.

这些试验包括，是否是随机，双盲，安慰剂对照或活动比较仪。

youdao

A total of 19 trials (16,390 patients) were included and these were all randomized, double-blinded and controlled with a placebo or with an active comparator.

总共有19个研究包含在内（有16390人参与），所有的研究都是随机的、双盲的、有安慰剂对照或者其他有效的对照。

youdao

Dr. Hartwell, who wasn't involved in the study, said social-network trials aren't likely to replace conventional randomized, double-blinded, placebo-controlled trials, the gold-standard for generating medical evidence.

WSJ: ALS Study Falls Short, But Use of Social Media Holds Promise