首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1088篇
  免费   24篇
各国政治   48篇
工人农民   46篇
世界政治   60篇
外交国际关系   25篇
法律   799篇
中国政治   21篇
政治理论   106篇
综合类   7篇
  2023年   4篇
  2022年   5篇
  2021年   9篇
  2020年   18篇
  2019年   25篇
  2018年   24篇
  2017年   23篇
  2016年   33篇
  2015年   18篇
  2014年   17篇
  2013年   75篇
  2012年   30篇
  2011年   29篇
  2010年   23篇
  2009年   19篇
  2008年   28篇
  2007年   16篇
  2006年   15篇
  2005年   29篇
  2004年   42篇
  2003年   37篇
  2002年   26篇
  2001年   101篇
  2000年   67篇
  1999年   73篇
  1998年   35篇
  1997年   4篇
  1996年   3篇
  1995年   8篇
  1994年   4篇
  1993年   7篇
  1992年   21篇
  1991年   18篇
  1990年   39篇
  1989年   26篇
  1988年   30篇
  1987年   23篇
  1986年   14篇
  1985年   13篇
  1984年   9篇
  1983年   9篇
  1982年   11篇
  1981年   8篇
  1980年   4篇
  1979年   12篇
  1978年   7篇
  1973年   2篇
  1971年   4篇
  1970年   3篇
  1968年   2篇
排序方式: 共有1112条查询结果,搜索用时 15 毫秒
991.
A female driver, 24 weeks pregnant, was wearing a three-point seatbelt in the manner usual for nonpregnant women, when her automobile collided head-on with another vehicle. A cardiotocographic examination after the accident revealed the fetus to be alive. Five days after the accident, however, a cardiotocographic examination showed fetal death. At that time, a transverse ecchymotic band on the lower abdominal wall that had not been observed at the first examination was noticed. Eight days after the accident, the mother delivered a macerated female fetus. At autopsy, the baby showed no abnormality, but there was a hematoma on the placental surface toward the uterus. These results suggest that the fetus died of abruptio placentae associated with incorrect placement of the lap belt.  相似文献   
992.
体位性窒息对心、肺功能影响的实验研究   总被引:1,自引:1,他引:0  
Chen Y  Hu B  Jing H  Cheng H  Zhang X  Wang S 《法医学杂志》2000,16(3):139-140
通过从股静脉将漂浮导管插入肺动脉的方法 ,检测悬挂前、悬挂期间和临终阶段呼吸、肺动脉压、心输出量的变化,探讨体位性窒息对心、肺功能影响及其在死亡中所起作用。结果:(1)悬挂前呼吸频率平稳 ,悬挂期间逐渐加快 ,临终前呈无规律状态 ;(2)悬挂期间及临终时肺动脉压比悬挂前明显升高;(3)悬挂前及悬挂期间的心输出量基本平稳 ,临终时比悬挂前及悬挂期间明显下降。本研究发现 ,悬挂可致呼吸失调 ,机体缺氧 ,导致心、肺功能障碍 ,属肺性死亡。其特征为呼吸停止是原发性的 ,心跳停止是继发的。  相似文献   
993.
GC双检测器技术筛选常见毒(药)物的可行性研究   总被引:3,自引:0,他引:3  
Sun YJ  Wu MT  Zhuo XY  Shen BH  Shen M 《法医学杂志》2000,16(2):81-83
利用气相色谱仪 ,在样品进样经单柱分离后通过Y形管连接至两个不同选择性检测器 (NPD/FID)的方法 ,考察气相色谱操作条件对双检测器响应比值的影响及其该法用于复杂样品测定的可行性。结果表明当实验条件保持不变时 ,NPD/FID响应比值具有较好的重现性。改变检测器操作参数和色谱条件对NPD/FID响应比值都有影响 ,但相对于某一参比物计算得到的相对NPD/FID响应比值受影响很小。样品中待测组份的浓度改变不影响NPD/FID响应比值。在有标准品比对的情况下 ,NPD/FID响应比值或相对NPD/FID响应比值可以作为定性分析的一个参数。  相似文献   
994.
Bao L  Zhang J  Shun Y  Zheng J  Shun H 《法医学杂志》2000,16(3):146-147
目的 :对法医学样品中微量液体血、血痕进行MN分型。方法 :利用抗M、抗N及抗血型糖蛋白A单抗 ,采用双位点一步ELISA方法。结果 :此法可检测的最低全血量约0 065μl,血痕约10~50ng。对455份新鲜血液及200份新鲜血痕的标本均正确检出 ;对58例陈旧血痕的检出率为96 6 %。结论 :此法准确率高且简便、快速 ,具有很大的实用价值。  相似文献   
995.
A cytosolic alanyl aminopeptidase (AAP-S) was purified to homogeneity from human liver cytosol. The molecular weight of the purified enzyme was calculated to be approximately 98,000 on TOF-MS and 90,000 on SDS-PAGE in the presence of beta-ME. These findings suggest that the enzyme exists as a monomeric form in human liver cytosol. The enzyme rapidly hydrolyzed the substrates Ala-, Lys- and Phe-MCAs, and moderately hydrolyzed Met-, Leu-, Tyr- and Lys-Ala-MCAs at pH ranging from 7.5 to 8.0. The order of the K(cat)/K(m) values of AAP-S at the optimal pH was Arg->Arg-Arg->Met->Leu->Lys->Phe->Lys-Ala->Tyr->Ala-MCAs. It was strongly inhibited by bestatin, leuhistin, actinonin, amastatin, 1, 10-phenanthroline, DFP, PCMBS, Zn(2+), Cd(2+), Co(2+), Cu((2+)), Hg(2+) and puromycin. AAP-S was approximately 80 times more sensitive than human seminal plasma AAP (aminopeptidase N, membrane type). The amino acid sequence of the first 60 residues of AAP-S was highly homologous with the N-terminal amino acid sequence of the rat liver puromycin-sensitive enkephalin-degrading aminopeptidase. These physicochemical properties and findings indicate that AAP-S from human liver cytosol is identical to those of other puromycin-sensitive aminopeptidase(s). Furthermore, with immunohistochemistry the enzyme was strongly stained in the cytoplasm of liver cells and renal tubules, and was ubiquitously localized in various human tissues.  相似文献   
996.
Morphological alterations occasionally found in the myocardium of methamphetamine (MAP) abusers include hypertrophy, atrophy, disarrangement of myofibrils and fibrosis. These cardiac alterations have been thought to be due to an indirect action of MAP via catecholamines released by MAP administration. However, the direct effect of MAP on cardiomyocytes is not clear. In previous studies, we showed that cell size of isolated adult rat ventricular cardiomyocytes (ARCs) exposed to MAP was larger than that of untreated cells in culture supplemented with 10% fetal calf serum (FCS). In this study, to determine further the direct effect of MAP on cardiomyocytes, cultured ARCs were exposed to 0.05, 0.1 and 0.5 mM MAP for 7 days in culture medium without FCS following 6-day normal culture in medium containing FCS. Myocyte size was measured and microtubular (MT) structures which were associated with functional disorder of hearts were immunohistochemically observed using confocal microscopy. The size in treated ARCs significantly increased time- and dose-dependently as compared with untreated cells, but it decreased 7 days after exposure to 0.5 mM MAP. The increases in cell size, however, were lower than that in serum-supplemented cultures. MT structures in intact ARCs appeared as a filamentous network throughout the cytoplasm and around the nucleus. MAP exposure for 3 days promoted MT assembly, but in 7-day treated cells, MT and actin structures were injured. These results suggested that MAP directly induced cellular hypertrophy and might lead to cardiac functional disorder.  相似文献   
997.
在欧洲的大学本科和研究生教学中,将韩国研究作为一门单独学科的时间并不长。必须承认,对于多数西方大学来说(尤其在西欧),如果没有韩国政府组织和韩国基金会等机构的直接支持,要把韩国研究作为一门单独的学科,是不可能的。不过,由于认识到了韩国研究的重要性,这些大学中对这个领域感兴趣和在攻读学位时选学韩国问题课程的学生越来越多。  相似文献   
998.
999.
Book reviews     
He Bochuan, China on the Edge: The Crisis of Ecology and Development, Berkeley: Pacific View Press, 1991.

Hu Ping, Zai lixiangyu xianshi zhijian (Between Ideal and Reality). Hong Kong: Tianyuan shuwu, 1990.

Hu Ping, Gei wo yige zhidian (Give me a Fulcrum). Taiwan: Lianjing chuban Gongshi, 1988.

Shi Bo, Waimenggu duli neimu (The inside story of Outer Mongolia's independence) (Beijing: Renmin Zhonguo chubanshe, 1993), 479pp, illustrations, maps.

Michael David Kwan, Broken portraits: Personal encounters with Chinese Students, San Francisco: China Books & Periodicals, 1990.

Liang An Guanxi yu Zhongguo Qiantu: Xueshu Yantaohui Lunwenchi (The Taiwan‐Mainland Relationship and the Future of China: Proceedings of a Scholarly Conference), Taipei, Taiwan: Minchu Jijinhui (Democracy foundation), 1992. 390 pages.  相似文献   

1000.
Fatal falls from great height are a frequently encountered setting in forensic pathology. They present – by virtue of a calculable energy transmission to the body – an ideal model for the assessment of the effects of blunt trauma to a human body.As multislice computed tomography (MSCT) has proven not only to be invaluable in clinical examinations, but also to be a viable tool in post-mortem imaging, especially in the field of osseous injuries, we performed a MSCT scan on 20 victims of falls from great height. We hereby detected fractures and their distributions were compared with the impact energy.Our study suggests a marked increase of extensive damage to different body regions at about 20 kJ and more. The thorax was most often affected, regardless of the amount of impacting energy and the primary impact site. Cranial fracture frequency displayed a biphasic distribution with regard to the impacting energy; they were more frequent in energies of less than 10, and more than 20 kJ, but rarer in the intermediate energy group, namely that of 10–20 kJ.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号