Methods One of the two classes of 78 nursing students in Grade 2003 and two of the four classes of total 225 students in Grade 2004 were randomized as experimental group and the rest as control group.

• 方法2003级护理专业本科2个班共78人,2004级护理专业专科4个班共225人,采用抽签法随机抽取2003级护理专业本科1个班、2004级护理专业专科2个班为试验组,其余为对照组。