Fig. 2From: Effectiveness of a combined problem-based learning and flipped classroom teaching method in ophthalmic clinical skill trainingThe comparison of preparation time in postgraduates with or without clinical experience in two groups. a the comparison of pre-class preparation time in all postgraduates; b the comparison of post-class preparation time in all postgraduates. *P < 0.05, **P < 0.01, ***P < 0.001Back to article page