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
| Communication is the sending of
information or news from one person to another. If human beings could not
communicate with one another, each person would have to learn everything for
himself. Although animals as well as men can communicate, so far as we know,
they can express only the simple emotions like pain, joy, fear, hunger, anger
and love. Some animals have a more advanced form of language using sounds, and
others use a wide range of sounds and face movements, but we still have much to
learn abo A. We should learn everything for ourselves. B. We would become unable to speak. C. We couldn’t live happily. D. We might have to do everything by ourselves. [单项选择]在睡眠中被噩梦突然惊醒，引起恐惧不安、心有余悸的睡眠行为障碍，是指（）
A. 睡眠-觉醒节律障碍 B. 睡行症 C. 梦魇 D. 夜惊 E. 失眠症 [单选题]患者，男，48 岁。发现乙肝病毒阳性 20 年，进来消瘦。CT 示肝脏有多个结节，肺部也有多个结节
从形态特征上您认为肝脏最准确的诊断是 A.结节性肝硬化 B. 肝细胞腺瘤 C. 肝结节性再生性增生 D. 局灶性结节状增生 E. 肝癌 [单项选择]“当事人中心”咨询理论是由（）提出来的。
A. 罗杰斯 B. 马斯洛 C. 弗洛伊德 D. 艾理斯 [判断题]《普安规》施工和维修作业须设置驻站联络员、现场防护员，且不得临时调换。
A.正确 B.错误 [单选题]转K6型交叉杆安全链松余量为( )。
A.80～115 mm B.80～100 mm C.80～120 mm D.80～125 mm [单选题]统一战线中存在两个联盟,其中处于基本和主要地位的是( )。
A.工人阶级和可以合作的地主阶级的联盟 B.工人阶级同农民阶级和其他劳动人民的联盟 C.工人阶级同民族资产阶级的联盟 D.工人阶级同一部分大资产阶级的联盟 [判断题]在半强式有效市场里，如果某上市公司公布了良好的业绩预增信息，股民此时迅速买入则可以获利。( )
[多选题]头孢曲松钠这种临床应用广泛的抗生素，如果和某些药物一起服用就会导致药效减弱、副作用增强的现象，在没有认识到这个问题时曾出现病人致死的案例，医学上称之为配伍禁忌。卫生主管部门在调查研究的基础上，没有禁止这种药物的使用，而是要求在药品使用说明书上写清配伍禁忌的有关情况说明。这一事例说明（）。
A.A认识是一个永远不能达到真理的过程 B.B认识是一个追求终极真理的过程 C.C认识是一个永无止境的无限发展过程 D.D认识是一个包含矛盾的辩证发展过程 E.E应该在普遍联系中客观地认识事物的性质和作用 我来回答: 提交
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