Combined effect of the smartphone addiction and physical activity on the depressive symptoms in secondary school students: a cross sectional study in Shanghai, China - Yang, Rui; Tan, Shuoyuan; Abdukerima, Gulqihra; Lu, Ting; Chen, Chen; Song, Lixin; Ji, Bing; Lv, Yipeng; Shi, Jianwei (Frontiers in Psychiatry, 2025)