单选题下列不符合良性畸胎瘤的描述是

单选题下列不符合萎缩的描述是

单选题 舅外甥女之间X连锁基因的近婚系数是 ( ) A、0 B、1/64 C、1/16 D、1/8 E、3/16

单选题激素作用的一般特性不包括

单选题食管癌最常见的组织学类型是

单选题真核基因组结构特点不包括

单选题British cancer' researchers have found that childhood leukaemia is caused by an infection and clusters of cases around industrial sites are the result of population mixing that increases exposure. The research published in the British Journal of Cancer backs up a 1988 theory that some as yet unidentified infection caused leukaemia--not the environmental factors widely blamed for the disease. "Childhood leukaemia appears to be an unusual result of a common infection," said Sir Richard Doll, an internationally-known cancer expert who first linked tobacco with lung cancer in 1950. "A virus is the most likely explanation. You would get an increased risk of it if you Suddenly put a lot of people from large towns in a rural area, where you might have people who had not been exposed to the infection. " Doll was commenting on the new findings by researchers at Newcastle University, which focused on a cluster of leukaemia cases around the Sellafield nuclear reprocessing plant in Cumbria in northern England. Scientists have been trying to establish why there was more leukaemia in children around the Sellafield area, but have failed to establish a link with radiation or pollution. The Newcastle University research by Heather Dickinson and Louise Parker showed the cluster of cases could have been predicted because of the amount of population mixing going on in the area, as large numbers of construction workers and nuclear staff moved into a rural setting. "Our study shows that population mixing can account for the (Sellafield) leukaemia cluster and that all children, whether their parents are incomers or locals, are at a higher risk if they are born in an area of high population mixing," Dickinson said in a statement issued by the Cancer Research Campaign, which publishes the British Journal of Cancer. Their paper adds crucial weight to the 1988 theory put forward by Leo Kinlen, a cancer epidemiologist at Oxford University, who said that exposure to a common unidentified infection through population mixing resulted in the disease.

单选题分泌活动日节律最为明显，清晨后可达分泌高峰的激素是

单选题下列结构中不属前庭器官的是

单选题关于局部神经元回路，不正确的论述是

单选题交叉性栓塞不发生于

单选题对于突触前抑制特点的描述，恰当的是

单选题女子尿中17－氧类固醇主要是哪种肾上腺皮质激素的代谢产物

单选题霍奇金淋巴瘤中陷窝细胞多出现在

单选题心肌的等长调节，通过改变下列哪个因素来调节心脏的泵血功能

单选题钙调蛋白参与多种酶作用的调控，它属于

单选题心率加快时以下列哪项升高为主( ) A．收缩压 B．舒张压 C．脉压 D．平均动脉压 E．中心静脉压

单选题下列不符合前列腺增生症的描述是

单选题下列符合肥大的病变是

单选题十二指肠球部可见直径约1 cm的圆形溃疡，不符合该患者疾病的描述是