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   3430430篇
  免费   241334篇
  国内免费   9375篇
耳鼻咽喉   48379篇
儿科学   111459篇
妇产科学   97265篇
基础医学   481771篇
口腔科学   97186篇
临床医学   308493篇
内科学   669738篇
皮肤病学   81693篇
神经病学   279967篇
特种医学   132670篇
外国民族医学   1122篇
外科学   516414篇
综合类   72785篇
现状与发展   11篇
一般理论   1301篇
预防医学   256868篇
眼科学   79096篇
药学   252471篇
  12篇
中国医学   7127篇
肿瘤学   185311篇
  2018年   35987篇
  2017年   27945篇
  2016年   32156篇
  2015年   36208篇
  2014年   50075篇
  2013年   75581篇
  2012年   99753篇
  2011年   105654篇
  2010年   63744篇
  2009年   61119篇
  2008年   99334篇
  2007年   106304篇
  2006年   107853篇
  2005年   103741篇
  2004年   100199篇
  2003年   97059篇
  2002年   93951篇
  2001年   160872篇
  2000年   164938篇
  1999年   139514篇
  1998年   40151篇
  1997年   35817篇
  1996年   35460篇
  1995年   34215篇
  1994年   31556篇
  1993年   29592篇
  1992年   109073篇
  1991年   105318篇
  1990年   102331篇
  1989年   99256篇
  1988年   91553篇
  1987年   89806篇
  1986年   84829篇
  1985年   81075篇
  1984年   60764篇
  1983年   51624篇
  1982年   30927篇
  1981年   27709篇
  1979年   55252篇
  1978年   39255篇
  1977年   33841篇
  1976年   31034篇
  1975年   34024篇
  1974年   40105篇
  1973年   38498篇
  1972年   36376篇
  1971年   33948篇
  1970年   31661篇
  1969年   30542篇
  1968年   28342篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
53.
54.
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.  相似文献   
55.
56.
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   
57.
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   
58.
Abstrakt 1. Ein nicht ausgefülltes und nicht unterschriebenes Aufkl?rungsformular in der Krankenakte bildet ein Indiz nicht für, sondern gegen die Durchführung eines Aufkl?rungsgespr?chs. 2. Wenn vor dem ?rztlichen Eingriff überhaupt keine Aufkl?rung erfolgt, genügt für den Beginn der Verj?hrung eines auf eine Aufkl?rungspflichtverletzung gestützten Anspruchs die Kenntnis vom Eintritt schwerwiegender Komplikationen. Nicht erforderlich ist das Wissen, dass sich ein typisches Risiko des Eingriffs verwirklicht hat.  相似文献   
59.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  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