Radiation occurs from three natural sources: radioactive material in the environment, such as in soil, rock, or building materials; cosmic rays; and substances in the human body, such as radioactive potassium in bone and radioactive carbon in tissues. These natural sources account for an exposure of about 100 millirems a year for the average American.
The largest single source of man-made radiation in medical x-rays, yet most scientists agree that hazards from this source are not as great as those from weapons-test fallout, since strontium-90 and carbon-14 become incorporated into the body, hence delivering radiation for an entire lifetime. (46) The issue is, however, by no means uncontroversial; indeed, the last two decades have witnessed intensified examination and dispute about the effects of low-level radiation.
A survey conducted in Britain confirmed that an abnormally high percentage of patients suffering from arthritis of the spine who had been treat
| When I was walking down the street the
other day, I happened to notice a small brown leather wallet lying on the
sidewalk. I picked it up and opened it to see if I could find out the owner’s
name. There was nothing inside it except some change and an old photograph--a
picture of a woman and a young girl about twelve years old, who looked like the
woman’s daughter. I put the photograph back and took the wallet to the police
station, where I handed it to the desk sergeant. Before I left, the sergeant
took down my name and address in case the owner might want to write and thank
me. That evening I went to have dinner with my aunt and uncle. They had also invited a young woman so that there would be four people at the table. Her face was familiar. I was quite sure that we had not met before, but I couldn’t remember where I had seen her. In the course of conve A. find some money B. find some gold C. find the owner’ s name D. find the owner’s photograph [单项选择]以下对健康检查的目的论述错误的一项是（）。
A. 尽早对有疾病或有身体缺陷的儿童采取矫治措施 B. 了解儿童生长发育和健康状况 C. 杜绝疾病的发生 D. 尽早发现儿童的疾病或身体缺陷 [单选题]扑救高层建筑火灾，进攻起点层一般选择在
A. 着火层下一、二层 B. 着火层 C.着火上层 D. 着火层上一、二层 [判断题]供电调度员发布停电作业命令时，受令人认真复诵，经确认无误后，方可给命令编号和批准时间，受令人要填写“接触网停电作业命令票”。
A.正确 B.错误 [单选题]在融合空域运行的XII级别无人机驾驶员，应至少持有带有飞机或直升机等级的()
A.商照和仪表等级 B.私照 C.商照 [单选题]【多选题】《中华人民共和国特种设备安全法》规定, 使用特种 设备未按照规定办理使用登记的,责令限期改正;逾期未改正的, 责令停止使用有关特种设备,处( )以上( C)以下罚款。
A.1 万元 B.2 万元 C.10 万元 [单项选择]医患沟通的含义是指
A. 思想沟通和语言沟通、心理沟通 B. 思想沟通和情感沟通、心理沟通 C. 思想沟通和情感沟通、语言沟通 D. 情感沟通和语言沟通、知识沟通 E. 知识沟通和思想沟通、心理沟通 [单选题]下列不属于妇科急腹症特点的是
A.与月经周期有关 B.常可出现腹膜刺激征 C.以下腹部或盆腔内痛为主 D.常伴有白带增多、阴道流血 E.有停经史、月经不规则 [单选题]进站预告信号或接近信号机的灯光熄灭、显示不明或显示不正确时，均视为进站信号机为( )状态。(技规)
A.关闭 B.开放 C.引导 [判断题]据研究，世界上只有中国是严格按照人的等级来划分建筑的等级。
[多选题] 关于远期结售汇违约处理， 下列说法正确的有（ ） 。
A. 经办行按市价对违约金额进行反向平盘 B. 违约产生的亏损由客户承担 C. 只能进行全额违约， 不存在部分违约 D. 违约产生的收益可由经办行按照商业原则进行处理 [单选题] 高等教育的经济功能主要表现在( )。
A. 高校是培养政治精英的摇篮 B. 高校是人实现社会化的场所 C. 高校是文化传承的基地 D. 高校是科技创新的重镇 我来回答: 提交
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