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   1574642篇
  免费   107537篇
  国内免费   3278篇
耳鼻咽喉   23175篇
儿科学   48809篇
妇产科学   47120篇
基础医学   223959篇
口腔科学   46179篇
临床医学   132539篇
内科学   305817篇
皮肤病学   35362篇
神经病学   123032篇
特种医学   62728篇
外国民族医学   476篇
外科学   244816篇
综合类   37463篇
现状与发展   6篇
一般理论   580篇
预防医学   108938篇
眼科学   37100篇
药学   117192篇
  4篇
中国医学   3628篇
肿瘤学   86534篇
  2018年   14749篇
  2016年   13138篇
  2015年   14732篇
  2014年   20474篇
  2013年   31318篇
  2012年   40473篇
  2011年   42716篇
  2010年   25924篇
  2009年   24853篇
  2008年   40784篇
  2007年   44548篇
  2006年   44968篇
  2005年   43401篇
  2004年   42160篇
  2003年   40753篇
  2002年   39961篇
  2001年   73540篇
  2000年   75443篇
  1999年   63897篇
  1998年   17083篇
  1997年   15670篇
  1996年   15027篇
  1995年   14202篇
  1994年   13299篇
  1992年   49161篇
  1991年   47888篇
  1990年   47052篇
  1989年   45847篇
  1988年   42659篇
  1987年   41984篇
  1986年   40186篇
  1985年   38230篇
  1984年   28601篇
  1983年   24307篇
  1982年   14620篇
  1981年   13226篇
  1979年   27483篇
  1978年   19615篇
  1977年   17022篇
  1976年   15396篇
  1975年   17557篇
  1974年   20786篇
  1973年   20344篇
  1972年   19364篇
  1971年   18143篇
  1970年   17278篇
  1969年   16490篇
  1968年   15565篇
  1967年   14009篇
  1966年   13139篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Severe tuberculosis (TB) requiring intensive care unit (ICU) care is rare but commonly known to be of markedly bad prognosis. The present study aimed to describe this condition and to determine the mortality rate and risk factors associated with mortality. Patients with confirmed TB admitted to ICU between 1990 and 2001 were retrospectively identified and enrolled. Clinical, radiological and bacteriological data at admission and during hospital stay were recorded. A multivariate analysis was performed to identify the predictive factors for mortality. A total of 58 TB patients (12 females, mean age 48 yrs) admitted to ICU were included. Mean Acute Physiology and Chronic Health Evaluation (APACHE) II score at admission was 13.1+/-5.6 and 22 of 58 (37.9%) patients required mechanical ventilation. The in-hospital mortality was 15 of 58 (25.9%); 13 (22.4%) patients died in the ICU. The mean survival of patients who died was 53.6 days (range 1-229), with 50% of the patients dying within the first 32 days. The factors independently associated with mortality were: acute renal failure, need for mechanical ventilation, chronic pancreatitis, sepsis, acute respiratory distress syndrome, and nosocomial pneumonia. These data indicate a high mortality of patients with tuberculosis requiring intensive care unit care and identifies new independently associated risk factors.  相似文献   
22.
Low molecular weight heparins are widely used in the prophylaxis and treatment of thrombotic disorders. The effect of low molecular weight heparins on coagulation was examined ultrastructurally in an animal model. A test and a control group was formed, each consisting of five rabbits. Nadroparine (225 Institute of Chaoy Unit/kg twice daily) was applied to the test group for 10 days. The control group received 1 ml saline solution subcutaneously. Blood and vascular tissue samples collected at the end of the 10th day were evaluated under a JEM 100 B electron microscope. Platelet degranulation and agglutination was observed in the control group. Fibrin materials were detected in the cytoplasms and surroundings of degranulated platelets. Erythrocyte accumulation was remarkable on the vascular endothelium with intact coagulation periods. In the test group, outer membranes of platelets, hyalomere, and granular structures in the granulomeres were detected to be nearly intact. There were rare erythrocytes in the large vascular lumens. The aggregation phase had occurred but no agglutination was detected. Nadroparine seems to preserve consistency of lipoprotein membranes of platelets and granular structures containing enzymes, which contribute to the coagulation mechanisms.  相似文献   
23.
Summary: A female patient with isovaleric acidaemia had a successful outcome from pregnancy.  相似文献   
24.
25.
26.
27.
AIM: Cardiovascular risk factors can be present in children and young adults. We previously found abnormal microvascular function in children who had glucose intolerance and insulin resistance. The aim of the present study was to investigate whether they also have abnormalities in left ventricular mass (LVM) and arterial stiffness. METHODS: We measured heart dimensions and LVM using echocardiography, and arterial stiffness using pulse wave analysis in 23 children with good glucose handling (postfeeding glucose: 3.9 to 5 mmol/L) and 21 with poor glucose handling (7.7 to 11.4 mmol/L). RESULTS: The time to pulse reflection was slightly shorter in the poorer glucose handlers (mean+/-SD: 143+/-10 vs 153+/-20 ms, P=0.04), suggestive of increased arterial stiffness. Also in this group, there were significant relationships between intraventricular septal thickness, blood pressure and body mass index, but not in the normal glucose handlers. CONCLUSIONS: We have found that normal children who are in the lowest quintile of glucose tolerance in comparison with their peers are exhibiting the first signs of arterial stiffening. In addition, we have seen the beginnings of a relationship between blood pressure, body mass index and left ventricular enlargement in this group. While these changes may not yet be clinically significant, their emergence might be further evidence of early predisposition to cardiovascular disease.  相似文献   
28.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  相似文献   
29.
30.
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