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   1441504篇
  免费   101715篇
  国内免费   3302篇
耳鼻咽喉   20914篇
儿科学   42812篇
妇产科学   40531篇
基础医学   202312篇
口腔科学   42096篇
临床医学   123569篇
内科学   283841篇
皮肤病学   32215篇
神经病学   117559篇
特种医学   58103篇
外国民族医学   448篇
外科学   223143篇
综合类   32229篇
现状与发展   6篇
一般理论   514篇
预防医学   100450篇
眼科学   33312篇
药学   107239篇
  4篇
中国医学   3139篇
肿瘤学   82085篇
  2018年   14184篇
  2016年   12782篇
  2015年   14404篇
  2014年   19996篇
  2013年   29573篇
  2012年   39682篇
  2011年   41645篇
  2010年   24710篇
  2009年   23864篇
  2008年   39464篇
  2007年   43098篇
  2006年   43288篇
  2005年   41937篇
  2004年   40652篇
  2003年   38998篇
  2002年   38463篇
  2001年   65634篇
  2000年   67174篇
  1999年   57153篇
  1998年   15910篇
  1997年   14489篇
  1996年   13775篇
  1995年   13039篇
  1994年   12162篇
  1992年   43950篇
  1991年   42387篇
  1990年   41665篇
  1989年   40614篇
  1988年   37896篇
  1987年   37322篇
  1986年   35795篇
  1985年   34017篇
  1984年   25532篇
  1983年   21662篇
  1982年   13229篇
  1981年   12021篇
  1979年   24468篇
  1978年   17508篇
  1977年   15233篇
  1976年   13719篇
  1975年   15629篇
  1974年   18469篇
  1973年   17926篇
  1972年   17167篇
  1971年   16039篇
  1970年   15231篇
  1969年   14647篇
  1968年   13697篇
  1967年   12313篇
  1966年   11466篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
41.
Summary: A female patient with isovaleric acidaemia had a successful outcome from pregnancy.  相似文献   
42.
43.
44.
45.
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   
46.
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   
47.
48.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  相似文献   
49.
50.
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