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   379篇
  免费   81篇
  国内免费   24篇
耳鼻咽喉   3篇
儿科学   3篇
妇产科学   28篇
基础医学   99篇
口腔科学   14篇
临床医学   33篇
内科学   51篇
皮肤病学   9篇
神经病学   15篇
特种医学   15篇
外科学   41篇
综合类   33篇
预防医学   14篇
眼科学   4篇
药学   40篇
中国医学   8篇
肿瘤学   74篇
  2024年   5篇
  2023年   26篇
  2022年   68篇
  2021年   77篇
  2020年   57篇
  2019年   39篇
  2018年   34篇
  2017年   41篇
  2016年   22篇
  2015年   11篇
  2014年   20篇
  2013年   17篇
  2012年   6篇
  2011年   10篇
  2010年   7篇
  2009年   12篇
  2008年   8篇
  2007年   9篇
  2006年   9篇
  2005年   2篇
  2004年   3篇
  2003年   1篇
排序方式: 共有484条查询结果,搜索用时 15 毫秒
1.
动脉粥样硬化是一种慢性炎症性疾病,粥样斑块慢性聚集并沉积于大中型动脉内膜,导致严重的狭窄和血运障碍,引发组织器官缺血缺氧。纳米药物相对于传统药物在动脉粥样硬化治疗中因其具有独特的优势而广泛受到关注。本文重点综述几种纳米靶向颗粒(系统)和外泌体靶向载药系统在抗动脉粥样硬化研究中的应用,简述代表性纳米材料的合成过程,对其靶向性进行分析,并概述纳米药物的益处和内在挑战。尽管面临着一些需要解决和完善的挑战,但是纳米颗粒和外泌体靶向载药治疗的前景广阔,并有望将其推广应用于临床实践中。  相似文献   
2.
目的:探讨M1型巨噬细胞源外泌体对卵泡膜细胞活力的影响及其作用机制。方法:采用脂多糖(LPS)处理Raw264.7小鼠巨噬细胞,构建M1型巨噬细胞模型及巨噬细胞-卵泡膜细胞共培养体系。超速离心法分离巨噬细胞分泌的外泌体;通过电镜、Western blot和纳米流式检测仪鉴定外泌体。体外分离培养小鼠卵泡膜细胞,与PKH67荧光标记的外泌体共孵育,观察卵泡膜细胞摄取外泌体的情况。CCK-8法检测细胞活力,流式细胞术分析细胞周期分布,q PCR及Western blot检测细胞周期蛋白依赖性激酶抑制因子1B(CDKN1B)的表达。结果:在巨噬细胞-卵泡膜细胞共培养体系中,LPS诱导的M1型巨噬细胞通过外泌体增强卵泡膜细胞活力。电镜、Western blot及纳米流式检测结果显示,巨噬细胞源外泌体被成功分离。PKH67标记的外泌体与卵泡膜细胞共孵育实验证实卵泡膜细胞能摄取大量巨噬细胞源外泌体。这些外泌体可增强卵泡膜细胞的活力,使卵泡膜细胞G0/G1期比例下降,S期比例升高,且卵泡膜细胞CDKN1B的m RNA及蛋白相对表达量均明显低于对照组。结论:卵泡膜细胞能摄取巨噬细胞分泌的外泌体。M1型巨噬细胞源外泌体通过抑制CDKN1B的表达而增强卵泡膜细胞的活力。  相似文献   
3.
Preterm delivery is a major obstetric health problem contributing to poor neonatal outcome including low birth weight, respiratory distress syndrome, gastrointestinal, immunologic, central nervous system, hearing, and vision problems. Worldwide, approximately 15 million babies are born prematurely each year. The critical question which remains is how to identify women destined to deliver preterm from those who will achieve a term delivery. Prostaglandins, in all mammals, are important in the parturient process. Increased intrauterine prostaglandin production is associated with labor and in fact prostaglandin E2 (PGE2) or analogs are widely used clinically for cervical ripening and labor induction. Measurements of circulating eicosanoids have been problematic because of the rapid and major clearance by the lungs and then kidneys resulting in very low concentrations in plasma. Moreover, since eicosanoids are produced by all mammalian tissues, the sources of the measured eicosanoids are unknown. Our understanding of how cells communicate has undergone a paradigm shift with the recognition of the role of exosomes in intercellular signaling. Recent publications have identified enzymes and products of arachidonic acid metabolism (eicosanoids) within exosomes. This review will explore the potential roles of exosomes in eicosanoid functions that are critical in preterm labor and delivery.  相似文献   
4.
Multiple pregnancies resulting from the transfer of more than one embryo pose a significant threat to offspring born through Assisted Reproductive Treatments (ART). Transferring one embryo at a time would eliminate this risk. However, current approaches of identifying the highest quality embryo to transfer are either unreliable (e.g. morphology assessment) or highly invasive and potentially detrimental to embryos (e.g. PGD). Approaches for non-invasive embryo selection would be a major advancement that would increase efficiency and reduce both the costs and the risks associated with ART. Exosomes are a particular subtype of extracellular vesicles (EVs) that are secreted from a wide range of cells, including placental and endometrium cells. Exosomes are very stable vesicles that contain a broad spectrum of molecules, including proteins, mRNAs and miRNAs. Very little is known about this form of cell-to-cell communication in the context of ovarian follicular biology and implantation, but emerging data suggest that exosomes secreted by the blastocyst could influence gene expression and receptivity of endometrial cells thereby controlling its own implantation. Here we review emerging findings regarding exosomal signalling in reproductive biology and the prospects for mapping blastocyst-derived exosomal profiles as a means for supporting single embryo transfer policies.  相似文献   
5.
外泌体(exosomes)是直径在30~100 nm,内含RNA、脂质和蛋白质的纳米级囊泡,来源于细胞内溶酶体微粒内陷形成的多囊泡体,与细胞膜融合后释放到胞外,是肿瘤微环境中细胞间通讯和遗传物质的重要载体。肿瘤在发生、发展过程中可通过外泌体与肿瘤微环境中的免疫细胞、内皮细胞和肿瘤相关成纤维细胞之间相互作用从而促进肿瘤的进展,其携带蛋白质、脂质和核酸等内容物释放到细胞外随着体液运输改变肿瘤微环境、促进肿瘤细胞增殖、加快血管形成及促进癌症发展;肿瘤微环境是由肿瘤细胞、巨噬细胞、成纤维细胞及细胞外基质等共同构成的局部稳态环境,在癌症的发生、复发、转移和化疗耐药等过程中发挥重要的作用。本综述着重讨论外泌体的生物学特性及对肿瘤微环境的影响,为研究及诊断治疗肿瘤提供新的思路。  相似文献   
6.
肿瘤治疗过程中会出现很多严重的不良反应,如何将药物特异性导向癌细胞就成为了肿瘤治疗中亟需解决的问 题。外泌体是由细胞分泌的、纳米级别的、双层脂质的盘状囊泡结构。正常细胞与肿瘤细胞均可分泌外泌体,供体细胞分泌的 外泌体携带着蛋白质、脂质和核糖核酸(包括microRNA和lncRNA),可直接被同组织内其周围的受体细胞所吸收;同时外泌体 几乎存在于唾液、血液、尿液、脑脊髓液等所有体液中,通过体液运输被不同组织内受体细胞所吸收,为受体细胞的生长提供必 要的营养物质。肿瘤细胞中往往可对外释放出高于正常组织的外泌体,在肿瘤发展过程中外泌体对肿瘤的生长、转移和血管 生成起到重要的作用;同时癌细胞所分泌的外泌体中有着可用来区别与其他细胞外泌体不同的特征性分子,可作为肿瘤临床 诊断的分子标志物,也可作为肿瘤分级、精准治疗及预后评估的重要依据。鉴于此,本文收集国外内相关研究资料,对外泌体 的生物学特征进行总结,并综述了其在临床肿瘤诊断、治疗中的作用及应用潜力,并对外泌体进一步的发展方向进行展望,以 期能为外泌体在临床肿瘤精准治疗中的应用提供理论支持。  相似文献   
7.
8.
ObjectiveExosomes have been shown to play a strong role in intercellular communication. While GMSCs have been extensively studied, less research exists on exosomes derived from GMSCs, especially on how exosomes affect macrophages. This study aimed to investigate the impact of GMSC-derived exosomes on macrophage polarization and phenotype under inflammatory conditions.MethodsExosomes were isolated from GMSCs-conditioned media by ultracentrifugation (UC) and characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western blot (WB). In vitro, GMSC-derived exosomes were co-incubated with macrophages for 24 h in the absence or presence of M1 polarizing conditions in the six-well plate. The protein and mRNA expression levels of M1 and M2 macrophage markers were detected and the supernatants were collected for an enzyme-linked immunosorbent assay (ELISA).ResultsExosomes were successfully isolated from GMSCs. Macrophages co-cultured with exosomes showed significantly decreased levels of the M1 markers Tumor Necrosis Factor-α (TNF-α), Interleukin-12 (IL-12), CD86 and Interleukin-1β (IL-1β). By contrast, M2 marker Interleukin-10 (IL-10) levels moderately increased. Meanwhile, similar results were acquired in the cell culture supernatants.ConclusionGMSC-derived exosomes may promote M1 macrophage transformation into M2 macrophages, reducing the pro-inflammatory factors produced by M1 macrophages.  相似文献   
9.
Alzheimer’s disease (AD), manifested by memory loss and a decline in cognitive functions, is the most prevalent neurodegenerative disease accounting for 60–80 % of dementia cases. But, to-date, there is no effective treatment available to slow or stop the progression of AD. Exosomes are small extracellular vesicles that carry constituents, such as functional messenger RNAs, non-coding RNAs, proteins, lipids, DNA, and other bioactive substances of their source cells. In the brain, exosomes are likely to be sourced by almost all cell types and involve in cell communication to regulate cellular functions. The yet, accumulated evidence on the roles of exosomes and their constituents in the AD pathological process suggests their significance as additional biomarkers and therapeutic targets for AD. This review summarizes the current reported research findings on exosomes roles in the pathogenesis, diagnosis, and treatment of AD.  相似文献   
10.
IntroductionApheresis platelets (APs) are clinically and crucially important in the prevention and treatment of bleeding in patients with thrombocytopenia or cancer. However, few researchers have addressed the variation of supernatant metabolites and exosome proteins in APs during storage and their effects on cancer cell proliferation.ObjectiveThis study was designed to explore the change rules of the metabolites and exosomal proteins of APs during storage and their effects on cancer cell proliferation.MethodsMetabolomics and proteomics were separately applied to analyze the variation of AP supernatant metabolites and exosomal proteins between freshly prepared day-0 and day-5 terminal-stored APs. Cell counting kit (CCK)-8 assay was performed to detect the effects of AP supernatants and exosomes on the proliferation of cancer cells.ResultsWe found that the supernatant metabolites and exosomal proteins in APs were significantly different on day 0 and day 5, and that many differential metabolites and exosomal proteins were associated with cancer characteristics. Furthermore, the day-5 AP supernatants had a greater inhibition of the proliferation of K562, HepG2, and HCT116 cancer cells, but the day-5 AP exosomes had no significant effect on the proliferation of these cancer cells.ConclusionThe variant terminal-stored AP supernatants may inhibit the proliferation of cancer cells but the variant terminal AP exosomes have no effect on cancer cell proliferation.  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