全文获取类型
收费全文 | 160802篇 |
免费 | 9208篇 |
国内免费 | 590篇 |
专业分类
耳鼻咽喉 | 1968篇 |
儿科学 | 5486篇 |
妇产科学 | 4195篇 |
基础医学 | 22607篇 |
口腔科学 | 3749篇 |
临床医学 | 12832篇 |
内科学 | 37961篇 |
皮肤病学 | 4920篇 |
神经病学 | 14784篇 |
特种医学 | 3689篇 |
外国民族医学 | 30篇 |
外科学 | 18564篇 |
综合类 | 879篇 |
现状与发展 | 1篇 |
一般理论 | 63篇 |
预防医学 | 14681篇 |
眼科学 | 2641篇 |
药学 | 11274篇 |
中国医学 | 498篇 |
肿瘤学 | 9778篇 |
出版年
2023年 | 1262篇 |
2022年 | 2717篇 |
2021年 | 5168篇 |
2020年 | 2801篇 |
2019年 | 4375篇 |
2018年 | 5015篇 |
2017年 | 3555篇 |
2016年 | 3759篇 |
2015年 | 4042篇 |
2014年 | 5631篇 |
2013年 | 7593篇 |
2012年 | 11083篇 |
2011年 | 11366篇 |
2010年 | 6304篇 |
2009年 | 5683篇 |
2008年 | 8947篇 |
2007年 | 9127篇 |
2006年 | 8704篇 |
2005年 | 8488篇 |
2004年 | 7811篇 |
2003年 | 7237篇 |
2002年 | 6781篇 |
2001年 | 3525篇 |
2000年 | 3593篇 |
1999年 | 3130篇 |
1998年 | 1295篇 |
1997年 | 1021篇 |
1996年 | 835篇 |
1995年 | 752篇 |
1994年 | 639篇 |
1993年 | 587篇 |
1992年 | 1442篇 |
1991年 | 1416篇 |
1990年 | 1265篇 |
1989年 | 1125篇 |
1988年 | 1012篇 |
1987年 | 976篇 |
1986年 | 911篇 |
1985年 | 864篇 |
1984年 | 678篇 |
1983年 | 587篇 |
1982年 | 430篇 |
1979年 | 540篇 |
1978年 | 397篇 |
1975年 | 396篇 |
1974年 | 436篇 |
1973年 | 454篇 |
1972年 | 396篇 |
1971年 | 371篇 |
1970年 | 368篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
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
23.
24.
25.
26.
27.
Increasing evidence suggests that human epidermal melanocytes play an important role in the skin immune system; however, a role of their pigmentation in immune and inflammatory responses is poorly examined. In the study, the expression of Toll‐like receptor 4 (TLR4) and inflammatory cytokines and chemokines by cultured normal melanocytes derived from lightly and darkly pigmented skin was investigated after cell stimulation with lipopolysaccharide (LPS). The basal TLR4 mRNA level in heavily pigmented cells was higher as compared to their lightly pigmented counterparts. Melanocyte exposure to LPS upregulated the expression of TLR4 mRNA and enhanced the DNA‐binding activity of NF‐κB p50 and p65. We found substantial differences in the LPS‐stimulated expression of numerous genes encoding inflammatory cytokines and chemokines between the cells with various melanin contents. In lightly pigmented melanocytes, the most significantly upregulated genes were nicotinamide phosphoribosyltransferase (NAMPT/visfatin), the chemokines CCL2 and CCL20, and IL6, while the genes for CXCL12, IL‐16 and the chemokine receptor CCR4 were the most significantly upregulated in heavily pigmented cells. Moreover, the lightly pigmented melanocytes secreted much more NAMPT, CCL2 and IL‐6. The results of our study suggest modulatory effect of melanogenesis on the immune properties of normal epidermal melanocytes. 相似文献
28.
Jae Eun Choi Tyler Werbel Zhenping Wang Chia Chi Wu Tony L. Yaksh Anna Di Nardo 《Journal of dermatological science》2019,93(1):58-64
Background
Rosacea is a chronic inflammatory skin condition whose etiology has been linked to mast cells and the antimicrobial peptide cathelicidin LL-37. Individuals with refractory disease have demonstrated clinical benefit with periodic injections of onabotulinum toxin, but the mechanism of action is unknown.Objectives
To investigate the molecular mechanism by which botulinum toxin improves rosacea lesions.Methods
Primary human and murine mast cells were pretreated with onabotulinum toxin A or B or control. Mast cell degranulation was evaluated by β-hexosaminidase activity. Expression of botulinum toxin receptor Sv2 was measured by qPCR. The presence of SNAP-25 and VAMP2 was established by immunofluorescence. In vivo rosacea model was established by intradermally injecting LL-37 with or without onabotulinum toxin A pretreatment. Mast cell degranulation was assessed in vivo by histologic counts. Rosacea biomarkers were analyzed by qPCR of mouse skin sections.Results
Onabotulinum toxin A and B inhibited compound 48/80-induced degranulation of both human and murine mast cells. Expression of Sv2 was established in mouse mast cells. Onabotulinum toxin A and B increased cleaved SNAP-25 and decreased VAMP2 staining in mast cells respectively. In mice, injection of onabotulinum toxin A significantly reduced LL-37-induced skin erythema, mast cell degranulation, and mRNA expression of rosacea biomarkers.Conclusions
These findings suggest that onabotulinum toxin reduces rosacea-associated skin inflammation by directly inhibiting mast cell degranulation. Periodic applications of onabotulinum toxin may be an effective therapy for refractory rosacea and deserves further study. 相似文献29.
30.
Tormo Nuria Giménez Estela Martínez-Navarro María Albert Eliseo Navalpotro David Torres Ignacio Gimeno Concepción Navarro David 《European journal of clinical microbiology & infectious diseases》2022,41(4):657-662
European Journal of Clinical Microbiology & Infectious Diseases - We compared the performance of an in-house-developed flow cytometry assay for intracellular cytokine staining (FC-ICS) and a... 相似文献