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   1335845篇
  免费   94297篇
  国内免费   2908篇
耳鼻咽喉   19717篇
儿科学   40226篇
妇产科学   38660篇
基础医学   187202篇
口腔科学   39817篇
临床医学   112615篇
内科学   262372篇
皮肤病学   30205篇
神经病学   106359篇
特种医学   53671篇
外国民族医学   435篇
外科学   208206篇
综合类   31046篇
现状与发展   6篇
一般理论   436篇
预防医学   92038篇
眼科学   31360篇
药学   100073篇
  4篇
中国医学   2988篇
肿瘤学   75614篇
  2018年   11737篇
  2015年   11871篇
  2014年   16684篇
  2013年   25237篇
  2012年   32993篇
  2011年   34859篇
  2010年   20728篇
  2009年   20224篇
  2008年   33570篇
  2007年   36674篇
  2006年   37248篇
  2005年   36006篇
  2004年   35081篇
  2003年   34058篇
  2002年   33586篇
  2001年   63614篇
  2000年   65323篇
  1999年   55386篇
  1998年   14650篇
  1997年   13459篇
  1996年   12938篇
  1995年   12221篇
  1994年   11467篇
  1992年   42761篇
  1991年   41281篇
  1990年   40555篇
  1989年   39553篇
  1988年   36964篇
  1987年   36412篇
  1986年   34900篇
  1985年   33103篇
  1984年   24825篇
  1983年   21053篇
  1982年   12667篇
  1981年   11568篇
  1980年   10774篇
  1979年   23924篇
  1978年   17069篇
  1977年   14835篇
  1976年   13387篇
  1975年   15269篇
  1974年   18085篇
  1973年   17563篇
  1972年   16813篇
  1971年   15718篇
  1970年   14914篇
  1969年   14346篇
  1968年   13460篇
  1967年   12015篇
  1966年   11258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