主页
学科
搜索
账户
常见问题
当前学科:中级接触网工
题目:
单选
160km/h及以下区段的线岔定位拉出值不大于()。
A . A、400mm
B . B、450mm
C . C、475mm
D . D、500mm
答案:
<查看本题扣1积分>
查看答案
答案不对?请尝试站内搜索
推荐知识点:
患者,男性,34岁,涕中带血1个月余,体检未见异常,外院鼻咽镜示鼻咽咽隐窝变浅,活检示鼻咽高分化鳞癌。放疗一段时间后,患者出现了头痛症状,临床怀疑放射性脑病,首选的检查为()
焊接中碳钢的主要工艺措施是()。
摘果在树桩盆景造型中有以下几种作用()。
频率升高时,会使汽轮发电机组转子加速,离心力增加,造成转子的部件损坏。
某城市2008年的城市人口数为500万,城市人口年平均增长率为3%,则5年后的城市人口预测值为()。
喷码机墨线应在回收口内径的()处。
遗忘的进程是不均衡的,呈现的趋势是()。
回答题: Exercise Being Good or BadCan exercise be a bad thing? Sudden death during or soon after strenuous exertion on the squash court or on the army training grounds, is not unheard of. 51 trained marathon runners are not immune to fatal heart attacks. But no one knows just 52 common these sudden deaths linked to exercise are. The registration andinvestigation of such 53 is very patchy; only a national survey could determine the true 54 of sudden deaths in sports. But the climate of medical opinion is shifting in 55 of exercise, for the person recovering from a heart attack as 56 as the average lazy individual. Training can help the victim of a heart attack bylowering the 57 of oxygen the heart needs at any given level of work 58 the patient can do more before reaching the point where chest pains indicate a heart starved of oxygen. The question is, should middle-aged people, 59 .particular, be screened for signs of heart disease before 60 vigorous exercise?Most cases of sudden death in sport are caused by lethal arrhythmias in the beating of the heart, often in people 61 undiagnosed coronary heart disease. In North America 62 over 35 is advised to have a physical check-up and even an exercise electrocardiogram. The British, on the whole, think all this testing isunnecessary. Not many people die from exercise, 63 , and ECGs ( 心电图 ) are notoriously inaccurate. However, two medical cardiologists at the Victoria Infirmary in Glasgow, advocate screening by exercise ECG for people over 40, or younger people 64 at risk of developing coronary heart disease. Individuals showing a particular abnormality in their ECGs 65 , they say, a 10 to 20 times greater risk of subsequently developing signs of coronary heart disease, or of sudden death.第51题应选:
内科疾病传变规律除伤寒按六经,温病按卫气营血或三焦,内伤杂病按脏腑病机规律传变外,还存在下列哪些传变规律()
属于时间绩效指标的是()