全文获取类型
收费全文 | 138377篇 |
免费 | 48102篇 |
国内免费 | 467篇 |
专业分类
耳鼻咽喉 | 2416篇 |
儿科学 | 5533篇 |
妇产科学 | 1901篇 |
基础医学 | 25643篇 |
口腔科学 | 6360篇 |
临床医学 | 18703篇 |
内科学 | 35472篇 |
皮肤病学 | 9329篇 |
神经病学 | 18892篇 |
特种医学 | 5382篇 |
外科学 | 20892篇 |
综合类 | 643篇 |
现状与发展 | 1篇 |
一般理论 | 46篇 |
预防医学 | 8941篇 |
眼科学 | 2879篇 |
药学 | 10944篇 |
中国医学 | 1431篇 |
肿瘤学 | 11538篇 |
出版年
2023年 | 515篇 |
2022年 | 1094篇 |
2021年 | 3047篇 |
2020年 | 5902篇 |
2019年 | 12037篇 |
2018年 | 11678篇 |
2017年 | 12471篇 |
2016年 | 13661篇 |
2015年 | 14085篇 |
2014年 | 14398篇 |
2013年 | 15546篇 |
2012年 | 9262篇 |
2011年 | 9107篇 |
2010年 | 11533篇 |
2009年 | 7523篇 |
2008年 | 5752篇 |
2007年 | 4589篇 |
2006年 | 4294篇 |
2005年 | 3896篇 |
2004年 | 3535篇 |
2003年 | 3222篇 |
2002年 | 3093篇 |
2001年 | 1857篇 |
2000年 | 1739篇 |
1999年 | 1177篇 |
1998年 | 481篇 |
1997年 | 434篇 |
1996年 | 399篇 |
1995年 | 352篇 |
1994年 | 291篇 |
1993年 | 311篇 |
1992年 | 666篇 |
1991年 | 676篇 |
1990年 | 589篇 |
1989年 | 628篇 |
1988年 | 623篇 |
1987年 | 619篇 |
1986年 | 541篇 |
1985年 | 538篇 |
1984年 | 443篇 |
1983年 | 361篇 |
1982年 | 280篇 |
1981年 | 268篇 |
1980年 | 232篇 |
1979年 | 329篇 |
1978年 | 276篇 |
1977年 | 200篇 |
1974年 | 218篇 |
1973年 | 231篇 |
1972年 | 187篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Enrique Luengo Izaskun Buendia Cristina Fernndez‐Mendívil Paula Trigo‐Alonso Pilar Negredo Patrycja Michalska Borja Hernndez‐García Cristina Snchez‐Ramos Juan A. Bernal Tsuneya Ikezu Rafael Len Manuela G. Lpez 《Journal of pineal research》2019,67(1)
Alterations in autophagy are increasingly being recognized in the pathogenesis of proteinopathies like Alzheimer's disease (AD). This study was conducted to evaluate whether melatonin treatment could provide beneficial effects in an Alzheimer model related to tauopathy by improving the autophagic flux and, thereby, prevent cognitive decline. The injection of AAV‐hTauP301L viral vectors and treatment/injection with okadaic acid were used to achieve mouse and human ex vivo, and in vivo tau‐related models. Melatonin (10 μmol/L) impeded oxidative stress, tau hyperphosphorylation, and cell death by restoring autophagy flux in the ex vivo models. In the in vivo studies, intracerebroventricular injection of AAV‐hTauP301L increased oxidative stress, neuroinflammation, and tau hyperphosphorylation in the hippocampus 7 days after the injection, without inducing cognitive impairment; however, when animals were maintained for 28 days, cognitive decline was apparent. Interestingly, late melatonin treatment (10 mg/kg), starting once the alterations mentioned above were established (from day 7 to day 28), reduced oxidative stress, neuroinflammation, tau hyperphosphorylation, and caspase‐3 activation; these observations correlated with restoration of the autophagy flux and memory improvement. This study highlights the importance of autophagic dysregulation in tauopathy and how administration of pharmacological doses of melatonin, once tauopathy is initiated, can restore the autophagy flux, reduce proteinopathy, and prevent cognitive decline. We therefore propose exogenous melatonin supplementation or the development of melatonin derivatives to improve autophagy flux for the treatment of proteinopathies like AD. 相似文献
62.
63.
64.
65.
66.
Very preterm children are at increased risk of reduced processing speed at 5 years of age,predicted by typical complications of prematurity and prenatal smoking 下载免费PDF全文
67.
Melatonin reduces oxidative stress and improves vascular function in pulmonary hypertensive newborn sheep 下载免费PDF全文
Flavio Torres Alejandro González‐Candia Camilo Montt Germán Ebensperger Magdalena Chubretovic María Serón‐Ferré Roberto V. Reyes Aníbal J. Llanos Emilio A. Herrera 《Journal of pineal research》2015,58(3):362-373
Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN. 相似文献
68.
Spontaneous generation of functional osteoclasts from synovial fluid mononuclear cells as a model of inflammatory osteoclastogenesis 下载免费PDF全文
Stinne R. Greisen Halldór Bjarki Einarsson Malene Hvid Ellen‐Margrethe Hauge Bent Deleuran Tue Wenzel Kragstrup 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2015,123(9):779-786
In osteoimmunology, osteoclastogenesis is understood in the context of the immune system. Today, the in vitro model for osteoclastogenesis necessitates the addition of recombinant human receptor activator of nuclear factor kappa‐B ligand (RANKL) and macrophage colony‐stimulating factor (M‐CSF). The peripheral joints of patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) are characterized by an immune‐mediated inflammation that can lead to bone destruction. Here, we evaluate spontaneous in vitro osteoclastogenesis in cultures of synovial fluid mononuclear cells (SFMCs) activated only in vivo. SFMCs were isolated and cultured for 21 days at 0.5–1.0 × 106 cells/mL in culture medium. SFMCs and healthy control peripheral blood monocytes were cultured with RANKL and M‐CSF as controls. Tartrate‐resistant acid phosphatase (TRAP) positive multinucleated cells were found in the SFMC cultures after 21 days. These cells expressed the osteoclast genes calcitonin receptor, cathepsin K, and integrin β3, formed lacunae on dentin plates and secreted matrix metalloproteinase 9 (MMP9) and TRAP. Adding RANKL and M‐CSF potentiated this secretion. In conclusion, we show that SFMCs from inflamed peripheral joints can spontaneously develop into functionally active osteoclasts ex vivo. Our study provides a simple in vitro model for studying inflammatory osteoclastogenesis. 相似文献
69.
70.