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   5689篇
  免费   298篇
  国内免费   24篇
耳鼻咽喉   44篇
儿科学   327篇
妇产科学   84篇
基础医学   677篇
口腔科学   91篇
临床医学   412篇
内科学   1220篇
皮肤病学   62篇
神经病学   439篇
特种医学   109篇
外科学   766篇
综合类   150篇
一般理论   1篇
预防医学   325篇
眼科学   225篇
药学   631篇
中国医学   78篇
肿瘤学   370篇
  2023年   52篇
  2022年   101篇
  2021年   229篇
  2020年   97篇
  2019年   146篇
  2018年   198篇
  2017年   132篇
  2016年   156篇
  2015年   178篇
  2014年   248篇
  2013年   328篇
  2012年   432篇
  2011年   455篇
  2010年   249篇
  2009年   212篇
  2008年   319篇
  2007年   302篇
  2006年   250篇
  2005年   254篇
  2004年   194篇
  2003年   177篇
  2002年   182篇
  2001年   83篇
  2000年   80篇
  1999年   82篇
  1998年   55篇
  1997年   28篇
  1996年   35篇
  1995年   27篇
  1993年   28篇
  1992年   40篇
  1991年   56篇
  1990年   56篇
  1989年   42篇
  1988年   34篇
  1987年   40篇
  1986年   25篇
  1985年   47篇
  1984年   31篇
  1983年   27篇
  1982年   23篇
  1981年   16篇
  1980年   16篇
  1979年   20篇
  1978年   23篇
  1977年   19篇
  1974年   15篇
  1973年   23篇
  1971年   17篇
  1969年   18篇
排序方式: 共有6011条查询结果,搜索用时 10 毫秒
101.
Transient neurologic dysfunction is a characteristic feature of migraine. About 20% of migraineurs may experience various symptoms in the absence of any headache at one time or another. Visual auras are the most common auras of migraine, and migraine is considered as the most common cause of transient vision loss in young patients. Sensory auras are the second most common migrainous auras. However, the literature is silent for isolated sensory aura as a migraine equivalent. Herein we report 14 patients with recurrent episodic paresthesia in the limbs and other body parts. All patients fulfilled the diagnostic criteria of “typical aura without headache” of ICHD‐3β. All patients were subjected to various investigations to rule out secondary causes. Ten patients received antimigraine drugs and all showed a positive response to therapy. Recurrent spontaneous paresthesia is quite common in the general population and many patients remain undiagnosed. We speculate that a subset of patients might be related to migrainous sensory auras.  相似文献   
102.
103.
104.
Parkin and the glial cell line–derived neurotrophic factor (GDNF) receptor RET have both been independently linked to the dopaminergic neuron degeneration that underlies Parkinson’s disease (PD). In the present study, we demonstrate that there is genetic crosstalk between parkin and the receptor tyrosine kinase RET in two different mouse models of PD. Mice lacking both parkin and RET exhibited accelerated dopaminergic cell and axonal loss compared with parkin-deficient animals, which showed none, and RET-deficient mice, in which we found moderate degeneration. Transgenic expression of parkin protected the dopaminergic systems of aged RET-deficient mice. Downregulation of either parkin or RET in neuronal cells impaired mitochondrial function and morphology. Parkin expression restored mitochondrial function in GDNF/RET-deficient cells, while GDNF stimulation rescued mitochondrial defects in parkin-deficient cells. In both cases, improved mitochondrial function was the result of activation of the prosurvival NF-κB pathway, which was mediated by RET through the phosphoinositide-3-kinase (PI3K) pathway. Taken together, these observations indicate that parkin and the RET signaling cascade converge to control mitochondrial integrity and thereby properly maintain substantia nigra pars compacta dopaminergic neurons and their innervation in the striatum. The demonstration of crosstalk between parkin and RET highlights the interplay in the protein network that is altered in PD and suggests potential therapeutic targets and strategies to treat PD.  相似文献   
105.
106.
107.
108.
109.

Introduction

The leaves of Clerodendrum phlomidis L.f. have been used in the Indian traditional system of medicine to treat several inflammatory diseases and arthritis. The aim of the present study was to assess the anti-inflammatory and anti-arthritic activities of the leaves of C. phlomidis and to isolate the active principle by bioactivity guided fractionation.

Materials and methods

To find the anti-inflammatory constituents from this plant, fractionations were performed with concurrent bioassays. Carrageenan-induced inflammation and Freund complete adjuvant (FCA)-induced arthritic rat models were used. The anti-inflammatory and anti-arthritic activities of the isolated compound were studied by assessing the histology of the joints, levels of lysosomal enzymes, protein-bound carbohydrates, acute phase protein, etc., in plasma, as well as by estimating the levels and expression of pro-inflammatory cytokines in the joints.

Results

Repeated fractionations and bioassays yielded a novel bioactive compound: 3-hydroxy, 2-methoxy-sodium butanoate. Treatment with this compound reduced the paw edema induced by carrageenan and FCA dose dependently. The levels of lysosomal enzymes and protein-bound carbohydrates decreased significantly upon treatment with the compound. The level of plasma acute phase protein was also decreased compared with control animals. Protein levels and mRNA expression of pro-inflammatory cytokines TNF, IL-1 and IL-6 in the joints were decreased significantly in a dose-dependent manner and the histopathological data also added evidence of the anti-arthritic property of the compound.

Conclusion

The 3-hydroxy,2-methoxy sodium butanoate isolated from plant leaves displays considerable potency in anti-inflammatory action and has a prominent anti-arthritic effect. This is the first report of this natural compound with bioactivity.  相似文献   
110.
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