白头翁汤的组成中不含有以下哪种药物()
A.黄连
B.黄芩
C.黄柏
D.秦皮
参考答案:B
电子商务的一般框架分为四个层次和两个支柱。四个层次自底向上依次是:网络层、 (27) 、报文和信息传播层和贸易服务层;两个支柱是 (28) 和相关技术标准。
A.应用层 B.商业传输层 C.系统运作层 D.多媒体信息发布层
Should RGS (regulator of G protein signaling) proteins be classified as GEFs (guanine nucleotide exchange factors) or GAPs (GTPase activating proteins) Explain what role this activity plays in modulating G-protein-mediated responses in animals and yeasts.