铁基催化剂对胜利褐煤液化的影响

目的：评价以问题为基础的学习（problem-based learning，PBL）相对于传统教学对国内护理专业学生理论考试成绩的影响。方法计算机检索CNKI（1979年至2013年3月）、VIP （1989年至2013年3月）、万方数据库（1982年至2013年3月），收集有关PBL和传统教学的对照研究。在严格质量评价的基础上，使用Stata 10.0软件进行Meta分析。结果共检索到659篇相关文献，经筛选最终纳入22篇文献进行Meta分析。分析结果，合并效应量SMD 合并=0.79，95％CI （0.55，1.03），P=0.000]，提示PBL与传统教学相比，能够提高护理专业学生理论成绩。结论 PBL教学对国内护理专业学生理论成绩的提高有促进作用。由于纳入分析的研究质量差异较大，有必要开展更多设计严谨、大样本的随机对照试验来验证。

Effects of Iron Based Catalysts on Liquefaction of Shengli Lignite

Objective To evaluate the theoretical knowledge level of Chinese nursing students based on the problem-based learning（PBL）versus traditional teaching methods. Methods Databases including CNKI （1979-2013.03）,VIP （1989-2013.03）and Wanfang （1982-2013.03）were searched （up to March,2013）for controlled studies comparing PBL and traditional teaching methods. The quality of included studies was critically evaluated and the data were analyzed by Stata 10.0 software. Results A total of 659 articles were retrieved but only 22 were included. Meta-analyses showed that there were significant differences between PBL and traditional teaching methods in improving theoreti-cal knowledge of nursing students（SMD merge=0.79,95%CI（0.55,1.03）,P=0.000）. Conclusions PBL can improve the theoretical scores of Chinese nursing students. However,the above conclusion needs to be confirmed by more large-scale randomized controlled trials of higher quality due to the limitation of studies include in this paper.