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   1459789篇
  免费   103050篇
  国内免费   3477篇
耳鼻咽喉   21294篇
儿科学   43497篇
妇产科学   40885篇
基础医学   203266篇
口腔科学   42569篇
临床医学   125058篇
内科学   287011篇
皮肤病学   31849篇
神经病学   117306篇
特种医学   58379篇
外国民族医学   435篇
外科学   228022篇
综合类   32934篇
现状与发展   7篇
一般理论   613篇
预防医学   103756篇
眼科学   34070篇
药学   108879篇
  6篇
中国医学   3155篇
肿瘤学   83325篇
  2018年   14435篇
  2016年   12600篇
  2015年   14315篇
  2014年   20281篇
  2013年   30746篇
  2012年   40962篇
  2011年   43278篇
  2010年   25493篇
  2009年   24521篇
  2008年   41020篇
  2007年   44782篇
  2006年   44976篇
  2005年   43792篇
  2004年   42646篇
  2003年   41159篇
  2002年   40554篇
  2001年   64896篇
  2000年   66433篇
  1999年   56760篇
  1998年   16146篇
  1997年   14650篇
  1996年   14105篇
  1995年   13339篇
  1994年   12410篇
  1992年   43632篇
  1991年   42148篇
  1990年   41329篇
  1989年   40310篇
  1988年   37721篇
  1987年   37136篇
  1986年   35635篇
  1985年   33937篇
  1984年   25682篇
  1983年   21826篇
  1982年   13668篇
  1981年   12581篇
  1980年   11646篇
  1979年   24520篇
  1978年   17659篇
  1977年   15376篇
  1976年   13869篇
  1975年   15713篇
  1974年   18532篇
  1973年   18002篇
  1972年   17120篇
  1971年   16034篇
  1970年   15192篇
  1969年   14570篇
  1968年   13658篇
  1967年   12177篇
排序方式: 共有10000条查询结果,搜索用时 15 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