PET探测原理是基于（）。 A.光电效应 B.康普顿效应 C.湮灭辐射 D.轫致辐射 发布时间：2017-06-01 07:58 │ 来源：www.tikuol.com 题型：单项选择题 问题： PET探测原理是基于（）。A.光电效应B.康普顿效应C.湮灭辐射D.轫致辐射E.电子对生成效应
题型：单项选择题 肠系膜上动脉狭窄的声像图特点是（）。①肠系膜上动脉管壁增厚并强回声斑块或血栓②CDFI：狭窄处及其远端呈杂色血流③禁食时狭窄处Vmax明显高于正常，舒张早期反向血流消失④禁食时狭窄处Vmax减低，舒张期反向血流减低A.①②④B.①②③C.①②D.以上各项均不是 查看答案
题型：单项选择题 完形填空 Tess went to her bedroom and pulled a glass jar from its hiding place. She poured all the coins out on the floor and counted it __1__. Then cautiously placing the __2__back in the jar, she made her way six blocks to the chemist's. She waited for the chemist to give her some __3__, but he was busy talking with a well-dressed gentleman at that moment.__4__she took a quarter from her jar and banged it on the glass counter. That did it! "And what do you want?" the chemist asked in an __5__tone of voice. He turned back__6__expecting a reply to his question. "I want to buy a __7__," Tess answered back to the chemist in the same annoyed tone. "My brother Andrew is really, really __8__. Daddy says only a miracle can save him. And I believe I can find it here. How much does it cost?" InstInstantly they __9__ talking. The well-dressed gentleman came up to Tess, and __10_ to ask how much money she had on her. "One dollar and eleven cents," Tess answered. "And it's all the money I have." "Well, what a coincidence(巧合). A dollar and eleven cents-the _11_ price of a miracle for your little brother," smiled the man. Actually, the gentleman was an expert surgeon in his field. He performed an _12_ on Andrew without charge and it wasn't long _13_ Andrew recovered. Mom and Dad were always _14_ how much the operation would have cost. Tess smiled. Only she knew exactly how much a miracle cost…one dollar and eleven cents…plus the _15_ of a little child.( )1. A. carefully( )2. A. currency ( )3. A. admission( )4. A. So ( )5. A. astonished( )6. A. by ( )7. A. pill ( )8. A. sick ( )9. A. started( )10. A. went down( )11. A. basic ( )12. A. action ( )13. A. after( )14. A. knowing( )15. A. faithB. contently B. cash B. attentionB. And B. appreciatedB. for B. miracle B. weak B. stopped B. broke down B. low B. experimentB. when B. wonderingB. chat C. carelessly C. change C. attractionC. But C. annoyed C. beyond C. medicine C. unhappy C. continued C. settled down C. exact C. operation C. until C. doubting C. fantasy D. considerately D. collection D. adjustment D. Or D. amused D. without D. drug D. naughty D. considered D. bent down D. average D. assignment D. before D. realizing D. curiosity 查看答案
题型：单项选择题 邮运单代单使用的原因是（）。A、出现货物分批运输，前后批次是同一承运人运输B、中途站临时拉卸邮件C、出现邮件分批运输，前后批次不是同一承运人运输D、始发站或中转站将航空邮运结算单遗失 查看答案