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   303篇
  免费   24篇
  国内免费   31篇
儿科学   30篇
妇产科学   4篇
基础医学   21篇
口腔科学   13篇
临床医学   50篇
内科学   63篇
皮肤病学   1篇
神经病学   15篇
特种医学   55篇
外科学   9篇
综合类   21篇
预防医学   16篇
眼科学   4篇
药学   43篇
中国医学   1篇
肿瘤学   12篇
  2023年   1篇
  2022年   2篇
  2021年   1篇
  2020年   1篇
  2019年   3篇
  2018年   3篇
  2017年   4篇
  2016年   1篇
  2015年   3篇
  2014年   9篇
  2013年   12篇
  2012年   5篇
  2011年   6篇
  2010年   9篇
  2009年   15篇
  2008年   11篇
  2007年   20篇
  2006年   10篇
  2005年   7篇
  2004年   4篇
  2003年   2篇
  2002年   4篇
  2001年   4篇
  2000年   1篇
  1999年   13篇
  1998年   13篇
  1997年   17篇
  1996年   15篇
  1995年   13篇
  1994年   19篇
  1993年   14篇
  1992年   9篇
  1991年   9篇
  1990年   6篇
  1989年   11篇
  1988年   6篇
  1987年   9篇
  1986年   7篇
  1985年   8篇
  1984年   4篇
  1983年   3篇
  1982年   8篇
  1981年   11篇
  1980年   3篇
  1979年   4篇
  1978年   2篇
  1977年   3篇
  1976年   7篇
  1975年   5篇
  1974年   1篇
排序方式: 共有358条查询结果,搜索用时 15 毫秒
81.
硝基甘油对狗缺血区冠脉循环的作用   总被引:1,自引:0,他引:1  
用实验性犬冠脉狭窄模型,冠脉内恒流灌注硝基甘油0.5μg/kg.min-1,使冠脉血流量(CBF)增加、远端小动脉压(DCP)、冠脉血管总阻力(RT)、小冠脉血管阻力(RS)及冠状静脉低切血粘(ηb)减少;而主动脉压和心率无明显变化。恒流灌注硝基甘油1μg/kg.min-1时,在开始5min内冠脉循环的变化同上,并伴大冠脉血管阻力(RL)减少,10 min后出现CBF减少和RT,RL及ηb增加。结果提示,硝基甘油有缓解和加重心肌缺血的双重作用,其作用可能与剂量张扩张远端小动脉压的程度有关。  相似文献   
82.
ABSTRACT. The pulsed Doppler principle enables us to study the bloodflow velocity at specific points in the heart and great vessels. In such aorto-pulmonary connections as patent dnctus arteriosus, aorto-pulmonary window and truncus arteriosus the bloodflow velocity patterns are typical of the malformation. Based on knowledge of these abnormal flow patterns the diagnoses of these malformations can be made.  相似文献   
83.
84.
85.
中国大陆地区妇女骨质疏松筛选工具探讨   总被引:3,自引:0,他引:3  
目的建立适用于中国大陆地区40岁及以上妇女的骨质疏松(osteoporosis,OP)筛选工具。方法以20~39岁妇女腰椎骨密度的均数和标准差作为参考值计算T—score。以双能X线骨密度仪(dual—energy X—ray absorptiometry,DxA)的测量结果作为金标准,采用二分类的Bayes判别分析,建立判别函数。结果我国大陆地区40岁及以上妇女OP筛选工具(osteoporosis screening tool for Chinese,OSTC)为:体重-2×年龄+50。判别准则为OSTC〉0为无OP危险性,OSTC≤0为有OP危险性。OSTC的正判率为75.78%,灵敏度为76.8%,特异度为75.1%,Kappa值为0.51(P=0.000),说明OSTC与DXA的判定结果一致性尚可。结论OSTC是一个简便的OP筛选工具。根据年龄、体重两个变量的简单计算,即可对我国大陆地区40岁及以上的妇女进行OP危险性的筛选。但OSTC没有得到外部数据的验证,其优劣还有待进一步评价。  相似文献   
86.
During venoarterial extracorporeal membrane oxygenation the right carotid artery is ligated in a hypoxic neonate. The aim of the present study was to compare the morphology and metabolism of the left and right basal ganglia in 10 neonates after extracorporeal membrane oxygenation, using proton magnetic resonance imaging and spectroscopy. Data could be obtained in 9 neonates. No significant metabolic differences were found between either the left or right basal ganglia, despite a small right-sided thalamic infarct in one child. Metabolism was normal in all cases. All the infants showed symmetrical neurodevelopment.

Conclusion: Ligation of the right carotid artery for venoarterial extracorporeal membrane oxygenation did not produce persistent changes in brain metabolism in the basal ganglia in this small group of patients.  相似文献   
87.
88.
C-reactive protein (CRP), a marker of inflammation, has been associated with cardiovascular disease. Risk of cardiovascular disease is increased in migraineurs with aura. Results from a clinical report, case–control and a cohort study suggest that CRP is elevated in migraineurs compared with non-migraineurs. We examined the proposed association in a case–control study nested within two large population-based studies. The relationship between migraine and CRP (high-sensitivity CRP) was studied in 5906 men and women aged 55.0 ± 8.5 years in the Reykjavik Study and 1345 men and women aged 27.7 ± 5.5 years from the Reykjavik Study for the Young. A modified version of the International Headache Society's criteria was used to categorize people into migraineurs (two or more symptoms) or non-migraineurs. Migraineurs with visual or sensory symptoms were further defined as having migraine with aura (MA) or without aura (MO). Multivariable-adjusted CRP levels were similar in migraineurs and non-migraineurs for men (0.83 vs. 0.79 mg/l, P  = 0.44) and for women (0.87 vs. 0.87 mg/l, P  = 0.90). When further stratified by migraine aura and age, no differences were found between non-migraineurs, MO and MA among men. In women, CRP levels were borderline higher in those with MO compared with non-migraineurs and those with MA (1.01 mg/l vs. 0.81 and 0.75 mg/l, P  = 0.08 and P  = 0.08) in age group 19–34 years, but significantly lower in age group 60–81 years (0.52 mg/l vs. 1.07 and 1.01 mg/l, P  = 0.007 and P  = 0.03). CRP levels were not increased among migraine sufferers compared with non-migraineurs. Older women migraineurs without aura had lower CRP values than non-migraineurs and migraineurs with aura.  相似文献   
89.
Two hundred and forty-six apparently healthy pregnant women aged 19-40 years, without symptoms were recruited (147 recruited during the dry season and 99 recruited during the rainy season) for the present study. Blood examinations for malaria parasites, Plasmodium falciparum specific-IgG concentration and serological reactivity with P. falciparum-histidine rich protein-2 (HRP-2) antigens were conducted on all the pregnant women during the dry and rainy seasons of the year. During the dry season, 109 (74%) of the recruited pregnant women without symptoms had P. falciparum parasitaemia, while 79 (80%) of the recruited pregnant women without symptoms had P. falciparum parasitaemia during the rainy season. However, the P. falciparum malaria parasites density was significantly raised during the dry season compared with that of in the rainy season (p < 0.05). Serological analysis with P. falciparum histidine rich protein-2 antigen (HRP-2) showed 108 (73%) and 71 (77%) of the pregnant women without symptoms as seropositive during the dry and rainy seasons respectively. The P. falciparum specific-IgG concentration was similar during both seasons in the HRP-2 seropositive pregnant women without symptoms (p > 0.05). The results showed no seasonal tide in the incidences of asymptomatic P. falciparum parasitaemia; however, the significantly raised parasitaemia during the dry season may suggest possible increased parasites tolerance. The P. falciparum specific-IgG concentration during both seasons may not be the primary effector mechanism offering tolerance in asymptomatic parasitaemia in pregnant women.  相似文献   
90.
TheFirstWorldChineseCongresofDigestionwasheldinBeijingfromOctober20to22,1998inthebeautifulcapitalcityofBeijing.Thespecificaim...  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