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   2473968篇
  免费   201813篇
  国内免费   4718篇
耳鼻咽喉   35515篇
儿科学   75299篇
妇产科学   64858篇
基础医学   347534篇
口腔科学   69805篇
临床医学   225490篇
内科学   488175篇
皮肤病学   49291篇
神经病学   209506篇
特种医学   99813篇
外国民族医学   886篇
外科学   376237篇
综合类   57719篇
现状与发展   2篇
一般理论   1135篇
预防医学   200325篇
眼科学   57705篇
药学   184476篇
  6篇
中国医学   4492篇
肿瘤学   132230篇
  2018年   26239篇
  2017年   20295篇
  2016年   22205篇
  2015年   25175篇
  2014年   36348篇
  2013年   55298篇
  2012年   74990篇
  2011年   78996篇
  2010年   46325篇
  2009年   44412篇
  2008年   74912篇
  2007年   79596篇
  2006年   80212篇
  2005年   78475篇
  2004年   75527篇
  2003年   72876篇
  2002年   71916篇
  2001年   113331篇
  2000年   117219篇
  1999年   99334篇
  1998年   29073篇
  1997年   26442篇
  1996年   26385篇
  1995年   25480篇
  1994年   23912篇
  1993年   22308篇
  1992年   79946篇
  1991年   77002篇
  1990年   74099篇
  1989年   71331篇
  1988年   66378篇
  1987年   65319篇
  1986年   61878篇
  1985年   59031篇
  1984年   44893篇
  1983年   38307篇
  1982年   23740篇
  1981年   21220篇
  1980年   19785篇
  1979年   41755篇
  1978年   29505篇
  1977年   24816篇
  1976年   23243篇
  1975年   24350篇
  1974年   30006篇
  1973年   28390篇
  1972年   26461篇
  1971年   24389篇
  1970年   22956篇
  1969年   21257篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Summary: A female patient with isovaleric acidaemia had a successful outcome from pregnancy.  相似文献   
63.
64.
65.
66.
67.
68.
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   
69.
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   
70.
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