英语语法分析

We performed a double-blind, multicenter study, comparing MMX mesalamine vs placebo for the treatment of active ulcerative colitis.

我们进行了一项双盲，多中心研究，比较了美沙美拉明与美沙酮对安慰剂治疗活动性溃疡性结肠炎的疗效。

This multicenter trial questions the benefits of DHA supplementation during pregnancy.

这项试验质疑了在孕期服用DHA补充剂的益处。

Epidemiology investigation on AS: To adopt the multicenter, maximus sample clinical survey.

AS临床流行病学调查：采用多中心，大样本临床调查。