简述加快烟草育种进程的方法?
患者男,15岁,因“发现阴囊肿物3个月余”来诊。查体:囊肿呈实性结节状。初诊意见:间叶组织恶性肿瘤。最特异的免疫组织化学检查是() ["desmin","SMA","myogenin","vimentin","acti"]
某施工企业年末资产总额为1258560元,年末流动负债为215310元,年末长期负债为185200元,则该企业年末的资产负债率为()。 ["A.11.72% ","B.14.72% ","C.17.11% ","D.31.82%"]
哪种细胞免疫表型有助于鉴别骨髓瘤细胞和正常浆细胞() ["CD38","CD56","CD95","CD22","C1q"]
关于骨肿瘤的生化检查,下列哪项是错误的() ["广泛溶骨性转移,血清钙常升高","成骨性骨肿瘤,血清碱性磷酸酶升高","前列腺癌播散,血清酸性磷酸酶升高","浆细胞骨髓瘤,总蛋白浓度升高","血清碱性磷酸酶正常,可排除恶性肿瘤"]
简述回交的遗传效应?