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   178036篇
  免费   1165篇
  国内免费   19篇
耳鼻咽喉   1128篇
儿科学   6742篇
妇产科学   3074篇
基础医学   17024篇
口腔科学   1542篇
临床医学   12627篇
内科学   31358篇
皮肤病学   743篇
神经病学   16755篇
特种医学   8943篇
外科学   29007篇
综合类   2330篇
一般理论   1篇
预防医学   18303篇
眼科学   2792篇
药学   9626篇
中国医学   626篇
肿瘤学   16599篇
  2023年   28篇
  2022年   54篇
  2021年   99篇
  2020年   66篇
  2019年   115篇
  2018年   21997篇
  2017年   17410篇
  2016年   19570篇
  2015年   984篇
  2014年   890篇
  2013年   915篇
  2012年   7190篇
  2011年   21219篇
  2010年   18912篇
  2009年   11618篇
  2008年   19652篇
  2007年   21868篇
  2006年   718篇
  2005年   2335篇
  2004年   3549篇
  2003年   4535篇
  2002年   2618篇
  2001年   291篇
  2000年   415篇
  1999年   191篇
  1998年   235篇
  1997年   234篇
  1996年   115篇
  1995年   129篇
  1994年   111篇
  1993年   74篇
  1992年   48篇
  1991年   97篇
  1990年   129篇
  1989年   81篇
  1988年   57篇
  1987年   44篇
  1986年   24篇
  1985年   31篇
  1984年   23篇
  1982年   27篇
  1980年   40篇
  1974年   21篇
  1939年   20篇
  1938年   60篇
  1937年   25篇
  1935年   22篇
  1934年   30篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
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   
62.
63.
64.
65.
66.
67.

Background  

This study aimed to investigate the signs of oral dryness in relation to different salivary variables and to correlate subjective complaints of oral dryness with salivary flow rate.  相似文献   
68.
Introduction Hypothalamic hamartomas are congenital malformations. Clinically, they can be asymptomatic, but they cause seizures, mental retardation and precocious puberty in many cases. Case report A 20-day-old boy with hypothalamic hamartoma and bilateral anophthalmia was presented. Except those, no other congenital anomaly was detected. Conclusion This is a rare case of hypothalamic hamartoma with bilateral anophthalmia. The mutations at SOX2 has an important role in the developing brain and eyes.  相似文献   
69.
Introduction Suprasellar arachnoid cysts are uncommon developmental anomalies that are most often diagnosed in childhood. Because the natural history and pathogenesis of these remain poorly defined, optimal treatment guidelines are not yet established.Case report We report a case of spontaneous disappearance of a suprasellar arachnoid cyst that persisted after a ventriculoperitoneal shunt performed 10 years earlier. A 5-year-old boy presented with impaired visual acuity and urinary incontinence. Magnetic resonance (MR) imaging showed a large suprasellar cyst with noncommunicating hydrocephalus. A ventriculoperitoneal shunt was put in place to alleviate current aggravation of hydrocephalus symptoms. Because of the persistent size of the cyst and signs of brainstem compression on a repeat computed tomography (CT), we recommended surgical exploration and decompression. However, the boy’s parents declined any further surgical treatment, and the patient was subsequently lost to follow-up for 10 years. When the patient returned to our clinic at the age of 15 years, a repeat MR scan showed a complete disappearance of the cyst. His family denied any significant interval history.Discussion This case represents only the third reported case of spontaneous disappearance of a suprasellar arachnoid cyst. We discuss possible mechanisms and clinical characteristics of the disappearance of the arachnoid cyst with review of the literature.  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