以下各药中,既可补肾阴,又可补肾阳且能固精缩尿的是
A.紫河车
B.沙苑子
C.菟丝子
D.锁阳
E.蛤蚧
参考答案:C
Let R and S be the relation respectively: Relation R: A B C Relation S: B C D 1 2 3 2 3 4 6 7 8 2 3 5 The number of tuplesthat the result of the expression R ∞ S (Here is the natural join of relations R and S) is
A.3
B.4
C.6
D.9
检测HBV感染最直接敏感的指标是血液中的()
A.HBsAg
B.HBeAg
C.HBcAg
D.抗HBe
E.HBV-DNA