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   183211篇
  免费   1476篇
  国内免费   75篇
耳鼻咽喉   1169篇
儿科学   6831篇
妇产科学   3248篇
基础医学   17763篇
口腔科学   1747篇
临床医学   13007篇
内科学   32628篇
皮肤病学   864篇
神经病学   17274篇
特种医学   9163篇
外科学   29425篇
综合类   2345篇
一般理论   5篇
预防医学   18720篇
眼科学   2901篇
药学   9975篇
中国医学   676篇
肿瘤学   17021篇
  2023年   102篇
  2022年   232篇
  2021年   347篇
  2020年   231篇
  2019年   283篇
  2018年   22173篇
  2017年   17547篇
  2016年   19740篇
  2015年   1195篇
  2014年   1169篇
  2013年   1187篇
  2012年   7623篇
  2011年   21669篇
  2010年   19142篇
  2009年   11845篇
  2008年   19941篇
  2007年   22210篇
  2006年   1013篇
  2005年   2644篇
  2004年   3778篇
  2003年   4662篇
  2002年   2771篇
  2001年   305篇
  2000年   449篇
  1999年   213篇
  1998年   270篇
  1997年   261篇
  1996年   135篇
  1995年   154篇
  1994年   124篇
  1993年   104篇
  1992年   57篇
  1991年   102篇
  1990年   146篇
  1989年   90篇
  1988年   67篇
  1987年   54篇
  1986年   38篇
  1985年   41篇
  1984年   28篇
  1983年   31篇
  1982年   34篇
  1980年   46篇
  1974年   27篇
  1969年   25篇
  1938年   60篇
  1937年   25篇
  1934年   30篇
  1932年   57篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
112.
Depressive symptoms in older adults are common, but the minority of elderly meet criteria for major depressive disorder. This has led to confusion regarding the recognition of diagnosis, approach to treatment, and monitoring of outcomes in this needy population. Few depressed older adults are willing to seek treatment from psychiatrists or mental health specialists. Treatment approaches to the depressive spectrum of disorders in late life, which encompasses major and minor depressive disorder, dysthymic disorder, and mood disorders related to medical conditions, must include evidence-based algorithms that can be delivered in a variety of health care settings. Several recent multisite trials have advanced the use of collaborative care models and the systematic stepwise approach to the treatment of depression and anxiety states in older adults. This offers the ability to provide effective treatment of depression for older adults, consistent with current guidelines, in primary care and specialized health care settings.  相似文献   
113.
114.
115.
116.
117.
Purpose Reelin is important in the guidance of neuronal stem cells in the central nervous system during normal development. We wished to determine whether reelin is expressed in the retina and cornea after injury. Methods Mice underwent laceration of their retina as well as corneal epithelial debridement. The mice were sacrificed at 3 days, and eyes were fixed and stained for reelin expression and reelin messenger ribonucleic acid (mRNA). Results In normal eyes, reelin was expressed only at very low levels in the ganglion cell layer of the retina and the endothelial cell layer of the cornea. In injured eyes, there was marked expression in reelin immunoreactivity in the retina and cornea. Reelin gene expression was seen in the retina and cornea. Conclusions Reelin is expressed during normal retinogenesis. This study shows that reelin is also upregulated following injury to the retina and cornea. The expression of reelin following injury suggests that reelin may play an important role in regulating stem cell trafficking in neuronal and nonneuronal tissues following injury similar to its role in normal organogenesis. For consideration of publication in Graefe’s Archive for Clinical and Experimental Ophthalmology.  相似文献   
118.
Background A recombinant form of the α2(IV)NC1 domain of type IV collagen has been shown to have potent anti-angiogenic activity although this peptide has not been studied in the context of proliferative retinopathies. In the current investigation we examined the potential for α2(IV)NC1 to regulate retinal microvascular endothelial cell function using a range of in vitro and in vivo assay systems. Materials and methods α2(IV)NC1 at concentrations between 0.1 and 1 μg/ml was added to retinal microvascular endothelial cells (RMECs) followed by assessment of cell attachment, proliferation and survival. This agent was also tested within a novel in vitro three-dimensional retinal angiogenesis assay and the number of angiogenic sprouts quantified. α2(IV)NC1 was also delivered intra-vitreally to mice with oxygen-induced proliferative retinopathy (OIR) and neovascularisation evaluated in comparison with vehicle-treated controls. Results RMECs treated with α2(IV)NC1 (0.1, 0.5 and 1 μg/ml) showed delayed attachment at 3 h post-seeding, although this deficit had been restored at the 6-h time point. BrdU assay of DNA replication revealed that confluent RMECs treated with α2(IV)NC1 showed no measurable response in comparison with vehicle-treated controls. By contrast, proliferation of sub-confluent RMECs was significantly reduced by α2(IV)NC1 at 0.5 μg/ml (P<0.01). α2(IV)NC1 also induced apoptosis in RMECs and inhibited angiogenesis of pre-existing retinal vascular networks in vitro (P<0.001). Intra-vitreal injection of α2(IV)NC1 in the OIR model significantly inhibited pre-retinal neovascularisation compared with vehicle-treated controls (P<0.001). Conclusion α2(IV)NC1 inhibits angiogenesis in the retinal microvasculature. This recombinant protein has potential for the treatment of neovascularisation in proliferative retinopathies. BioStratum Inc. did not sponsor this research in any way. None of the authors are paid consultants with this company.  相似文献   
119.
120.
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