COPENHAGEN, April 27 (Xinhua) -- As the World Tai Chi Day approaches, a two-day event promoting Chinese Tai Chi culture was held from Friday to Saturday, attracting hundreds of enthusiasts from across ...

狄拉克的《量子力学原理》是最经典的量子力学教材之一，有诸多开创性的意义。然而其高度精炼与严格的表述，常让初学者望而却步。这部教材的价值在于展现理论物理的逻辑美感，却未必适配基础阶段的知识建构。作为近100年前的著作，该书也必然存在一些内容缺憾。但如果 ...