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   206626篇
  免费   2689篇
  国内免费   160篇
耳鼻咽喉   1431篇
儿科学   7044篇
妇产科学   3359篇
基础医学   20682篇
口腔科学   2518篇
临床医学   14371篇
内科学   38209篇
皮肤病学   1496篇
神经病学   18577篇
特种医学   10090篇
外科学   34260篇
综合类   2471篇
一般理论   1篇
预防医学   19043篇
眼科学   3413篇
药学   11873篇
中国医学   668篇
肿瘤学   19969篇
  2023年   157篇
  2022年   336篇
  2021年   585篇
  2020年   341篇
  2019年   436篇
  2018年   22388篇
  2017年   17768篇
  2016年   19940篇
  2015年   1474篇
  2014年   1523篇
  2013年   1670篇
  2012年   8291篇
  2011年   22409篇
  2010年   19619篇
  2009年   12226篇
  2008年   20700篇
  2007年   22899篇
  2006年   1918篇
  2005年   3601篇
  2004年   4687篇
  2003年   5635篇
  2002年   3732篇
  2001年   1556篇
  2000年   1729篇
  1999年   1355篇
  1998年   602篇
  1997年   539篇
  1996年   391篇
  1995年   384篇
  1994年   344篇
  1993年   300篇
  1992年   858篇
  1991年   806篇
  1990年   859篇
  1989年   778篇
  1988年   765篇
  1987年   665篇
  1986年   638篇
  1985年   632篇
  1984年   412篇
  1983年   346篇
  1982年   173篇
  1980年   171篇
  1979年   321篇
  1978年   216篇
  1977年   154篇
  1975年   154篇
  1974年   232篇
  1973年   152篇
  1972年   165篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
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   
85.
86.
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   
87.
88.
89.
90.
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