图书馆购买的很多数据库是可以实现手机访问的,其中一部分数据库有移动客户端(app),下列哪个数据库暂时还没有移动客户端( ) A. Web of Knowledge B. American Chemical Society(ACS) C. EBSCOHost平台 D. ISI EMERGINGMARKETS
【单选题】A disk is rotating about its central axis like a merry-go-round (旋转木马) . The angular position θ (t) of a reference line on the disk is given by θ = -1.00 – 0.60 t + 0.25 t 2 . How is the expression f...