A.必須設(shè)立對(duì)照 B.隨機(jī)分配實(shí)驗(yàn)對(duì)象到實(shí)驗(yàn)組和對(duì)照組 C.實(shí)驗(yàn)進(jìn)行的方向是隨著實(shí)驗(yàn)開始向前進(jìn)行的 D.對(duì)實(shí)驗(yàn)組施加控制的干預(yù)措施或消除某種因素 E.以上都正確
A.Iodine Deficiency Disease B.Iodine Deficiency Disorders C.Iodine Defect Disease D.Iodine Defect Disorders E.Iodide Deficiency Disease
A.鐵 B.鈣 C.砷 D.氟 E.硒