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   182328篇
  免费   1446篇
  国内免费   41篇
耳鼻咽喉   1254篇
儿科学   6795篇
妇产科学   3158篇
基础医学   17531篇
口腔科学   2379篇
临床医学   12966篇
内科学   32130篇
皮肤病学   841篇
神经病学   17021篇
特种医学   8979篇
外科学   29402篇
综合类   2341篇
一般理论   1篇
预防医学   18952篇
眼科学   2907篇
药学   9967篇
中国医学   688篇
肿瘤学   16503篇
  2023年   102篇
  2022年   237篇
  2021年   385篇
  2020年   268篇
  2019年   345篇
  2018年   22260篇
  2017年   17580篇
  2016年   19772篇
  2015年   1209篇
  2014年   1227篇
  2013年   1207篇
  2012年   7574篇
  2011年   21705篇
  2010年   19150篇
  2009年   11789篇
  2008年   19870篇
  2007年   22103篇
  2006年   833篇
  2005年   2446篇
  2004年   3532篇
  2003年   4477篇
  2002年   2606篇
  2001年   328篇
  2000年   444篇
  1999年   202篇
  1998年   217篇
  1997年   207篇
  1996年   107篇
  1995年   114篇
  1994年   107篇
  1993年   69篇
  1992年   64篇
  1991年   116篇
  1990年   152篇
  1989年   96篇
  1988年   68篇
  1987年   54篇
  1986年   40篇
  1985年   45篇
  1984年   38篇
  1983年   31篇
  1982年   32篇
  1980年   46篇
  1974年   30篇
  1969年   25篇
  1938年   60篇
  1937年   25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 0 毫秒
81.
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   
82.
83.
84.
85.
86.
87.
Currently few subjective measures of Quality of Life (QoL) are available for use in developing countries, which limits their theoretical, methodological, and practical contribution (for example, exploring the relationship between economic development and QoL, and ensuring effective and equitable service provision). One reason for this is the difficulty of ensuring that translated measures preserve conceptual, item, semantic, operational, measurement; and functional equivalence (Herdman, M., Fox-Rushby, J., & Badia, X. (1998). Quality of Life Research, 7, 331), which is illustrated by an account of the translation, pre-piloting, and administration of a new individualised QoL measure, the Global Person Generated Index or 'GPGI'. The GPGI is based on the widely used Patient Generated Index (Ruta, Camfield, & Martin, (2004) Quality of Life Research, 13, 1545.) and offers many of the advantages of the participatory approaches commonly used in developing countries, with added methodological rigour, and quantitative outcomes. It was successfully validated in Bangladesh, Thailand, and Ethiopia, using quantitative and qualitative methods--open-ended, semi-structured interviews (SSIs), conducted immediately post-administration. Both the measure and method of 'qualitative validation' described later in the paper offer an exciting alternative for future researchers and practitioners in this field. The quantitative results suggest the GPGI shows cultural sensitivity, and is able to capture both the areas that are important to respondents, and aspects of life one would expect to impact on QoL in developing countries. There were strong correlation between scores from the GPGI and SSIs for the area of health, and moderate correlations for 'material wellbeing' (MWB)('Material wellbeing' refers to respondents' perceptions of their achievement in the areas of farming, debt reduction, assets, crops, livestock, job, land, property, and agriculture) and children. Weak to moderate correlations were observed between the Satisfaction with Life Scale and the GPGI; however, the highest coefficient was between the GPGI and the most conceptually similar item. Statistically significant differences were seen in GPGI scores between rich and poor, urban and rural respondents, and different countries. Health and material wellbeing scores, derived from the SSIs, also showed a linear relationship with GPGI scores, with a suggestion of curvilinearity at the higher levels, as predicted by a general QoL causal model. In conclusion, the GPGI has great potential for use in this area, especially when supported by extensive interviewer training, and supplemented with a cognitive appraisal schedule.  相似文献   
88.
89.

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   
90.
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   
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