血凝素是流感病毒的主要表面抗原,诱导机体产生中和抗体。
确定在本地区建港后,选择建港具体地点起决定性因素的是() ["港口与城市协调关系","当地的自然条件","港口集疏运方式","环保要求"]
在中国()时代自然事物真正作为审美对象进入人的视野。
Which statement about data center access layer design modes is correct?() [" The access layer is the first oversubscription point in a data center design."," When using a Layer 2 loop-free design, VLANs are extended into the aggregation layer."," When using a Layer 2 looped design, VLANs are not extended into the aggregation layer."," When using a Layer 3 design, stateful services requiring Layer 2 connectivity are provisionedfrom the aggregation layer."," The data center access layer provides the physical-level connections to the server resourcesand only operates at Layer 3."]
下列说法错误的是() ["点涡的形成与粘性力有关。","实际流体中,点涡的强度随时间的变化而变化。","涡强沿着涡管是不变的。","涡管的形状一定是圆的。"]
某企业本月生产甲产品,月初在产品费用与本月投入生产费用合计为20000元,月末 在产品费用为1500元。该产成品发生可修复废品损失1000元;发生不可修复废品成本2000元;废品残料作价500元入库;由过失人赔偿300元。甲产品合格品187件。计算合格品单位成本。