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   3360489篇
  免费   250813篇
  国内免费   6343篇
耳鼻咽喉   51751篇
儿科学   103960篇
妇产科学   94154篇
基础医学   477818篇
口腔科学   98830篇
临床医学   296128篇
内科学   652248篇
皮肤病学   74234篇
神经病学   277602篇
特种医学   133927篇
外国民族医学   1251篇
外科学   508927篇
综合类   78671篇
现状与发展   7篇
一般理论   1316篇
预防医学   256749篇
眼科学   82940篇
药学   248026篇
  8篇
中国医学   6430篇
肿瘤学   172668篇
  2018年   31884篇
  2016年   27547篇
  2015年   33153篇
  2014年   47051篇
  2013年   71328篇
  2012年   92861篇
  2011年   97792篇
  2010年   58931篇
  2009年   57089篇
  2008年   93623篇
  2007年   100058篇
  2006年   101326篇
  2005年   98488篇
  2004年   94771篇
  2003年   90929篇
  2002年   89086篇
  2001年   150167篇
  2000年   155218篇
  1999年   131826篇
  1998年   38223篇
  1997年   34882篇
  1996年   34325篇
  1995年   33315篇
  1994年   31254篇
  1993年   29051篇
  1992年   106078篇
  1991年   102230篇
  1990年   99169篇
  1989年   95937篇
  1988年   89155篇
  1987年   87888篇
  1986年   83691篇
  1985年   79913篇
  1984年   60628篇
  1983年   51598篇
  1982年   31720篇
  1981年   28386篇
  1980年   26631篇
  1979年   57413篇
  1978年   40915篇
  1977年   34959篇
  1976年   32247篇
  1975年   35098篇
  1974年   42518篇
  1973年   40810篇
  1972年   38569篇
  1971年   35845篇
  1970年   33848篇
  1969年   31887篇
  1968年   29278篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Summary: A female patient with isovaleric acidaemia had a successful outcome from pregnancy.  相似文献   
52.
53.
54.
55.
56.
57.
58.
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   
59.
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   
60.
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