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   1358099篇
  免费   95917篇
  国内免费   2966篇
耳鼻咽喉   19911篇
儿科学   40866篇
妇产科学   39160篇
基础医学   189978篇
口腔科学   40133篇
临床医学   114847篇
内科学   266706篇
皮肤病学   30837篇
神经病学   108219篇
特种医学   54502篇
外国民族医学   436篇
外科学   211478篇
综合类   31401篇
现状与发展   6篇
一般理论   494篇
预防医学   94056篇
眼科学   32148篇
药学   101567篇
  4篇
中国医学   3004篇
肿瘤学   77229篇
  2018年   12105篇
  2015年   12256篇
  2014年   17291篇
  2013年   26116篇
  2012年   34306篇
  2011年   36189篇
  2010年   21492篇
  2009年   20892篇
  2008年   34866篇
  2007年   38012篇
  2006年   38567篇
  2005年   37408篇
  2004年   36431篇
  2003年   35349篇
  2002年   34857篇
  2001年   63990篇
  2000年   65614篇
  1999年   55691篇
  1998年   14940篇
  1997年   13728篇
  1996年   13190篇
  1995年   12450篇
  1994年   11667篇
  1992年   43003篇
  1991年   41501篇
  1990年   40735篇
  1989年   39731篇
  1988年   37132篇
  1987年   36568篇
  1986年   35047篇
  1985年   33291篇
  1984年   25006篇
  1983年   21234篇
  1982年   12877篇
  1981年   11786篇
  1980年   10964篇
  1979年   24053篇
  1978年   17212篇
  1977年   14970篇
  1976年   13486篇
  1975年   15376篇
  1974年   18197篇
  1973年   17660篇
  1972年   16882篇
  1971年   15785篇
  1970年   14962篇
  1969年   14412篇
  1968年   13497篇
  1967年   12063篇
  1966年   11304篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Summary: A female patient with isovaleric acidaemia had a successful outcome from pregnancy.  相似文献   
32.
33.
34.
35.
To determine if impaired energy metabolism might contribute to some aspects of Alzheimer disease (AD), including the vulnerability of the CA1 region of the hippocampal formation and the altered cytoskeleton evident in neurofibrillary tangles, we examined the effects of metabolic poisons on neuronal damage and cytoskeletal disruption in the hippocampal formation. Intrahippocampal injection of 3-nitropropionic acid (3-NP) and malonic acid resulted in neuronal death, particularly in CA1. Cytoskeletal disruption included loss of dendritic MAP2, but sparing of axonal τ. MK-801 (a noncompetitive NMDA receptor antagonist) did not atenuate the lesions produced by intrahippocampal injection of malonate. MK-801, however, was effective against intrastriatal malonate. Acute systemic 3-NP resulted in neuronal damage and cytoskeletal disruption in the CA1 region of the hippocampal formation, including an extensive loss of MAP2 immuno-reactivity, but sparing of τ. The neuronal loss in CA1 was delayed as compared to striatum. Chronic intraventricular infusion of 3-NP produced a different pattern of neuronal damage. Loss of τ-1 immuno-reactivity was observed in CA3 and CA1 s. oriens, whereas MAP2 immunostaining was preserved. These results demonstrate that chronic and acute administration of metabolic inhibitors produce distinct patterns of neuronal damage and cytoskeletal disruption. The results further suggest a differential involvement of the NMDA receptor in malonate-induced neuronal damage in striatum as compared to the hippocampus. The pattern of neuronal damage and cytoskeletal disruption observed following acute metabolic impairment resembled some aspects of neurofibrillary pathology in AD, but did not result in τ hyperphosphorylation.  相似文献   
36.
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   
37.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  相似文献   
38.
39.
40.
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