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   4446篇
  免费   1077篇
  国内免费   480篇
耳鼻咽喉   16篇
儿科学   29篇
妇产科学   61篇
基础医学   895篇
口腔科学   83篇
临床医学   463篇
内科学   499篇
皮肤病学   38篇
神经病学   165篇
特种医学   77篇
外国民族医学   1篇
外科学   240篇
综合类   910篇
预防医学   93篇
眼科学   100篇
药学   465篇
中国医学   75篇
肿瘤学   1793篇
  2024年   45篇
  2023年   291篇
  2022年   595篇
  2021年   810篇
  2020年   696篇
  2019年   440篇
  2018年   314篇
  2017年   342篇
  2016年   370篇
  2015年   609篇
  2014年   485篇
  2013年   306篇
  2012年   214篇
  2011年   202篇
  2010年   113篇
  2009年   65篇
  2008年   32篇
  2007年   19篇
  2006年   10篇
  2005年   6篇
  2004年   2篇
  2003年   1篇
  2002年   2篇
  2001年   3篇
  2000年   2篇
  1999年   3篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   3篇
  1992年   1篇
  1990年   2篇
  1989年   4篇
  1985年   3篇
  1984年   3篇
  1983年   2篇
  1979年   1篇
  1978年   1篇
  1973年   1篇
排序方式: 共有6003条查询结果,搜索用时 15 毫秒
31.
32.
IntroductionAlpha-1 antitrypsin deficiency (AATD) is a genetic condition resulting in lung and liver disease with a great clinical variability. MicroRNAs have been identified as disease modifiers; therefore miRNA deregulation could play an important role in disease heterogeneity. Members of miR-320 family are involved in regulating of multiple processes including inflammation, and have potential specific binding sites in the 3′UTR region of SERPINA1 gene. In this study we explore the involvement of miR-320c, a member of this family, in this disease.MethodsFirstly in vitro studies were carried out to demonstrate regulation of SERPINA1 gene by miR-320. Furthermore, the expression of miR-320c was analyzed in the blood of 98 individuals with different AAT serum levels by using quantitative PCR and expression was correlated to clinical parameters of the patients. Finally, HL60 cells were used to analyze induction of miR-320c in inflammatory conditions.ResultsOverexpression of miR-320 members in human HepG2 cells led to inhibition of SERPINA1 expression. Analysis of miR-320c expression in patient's samples revealed significantly increased expression of miR-320c in individuals with pulmonary disease. Additionally, HL60 cells treated with the pro-inflammatory factor lipopolysaccharide (LPS) showed increase in miR-320c expression, suggesting that miR-320c responds to inflammation.ConclusionOur findings demonstrate that miR-320c inhibits SERPINA1 expression in a hepatic cell line and its levels in blood are associated with lung disease in a cohort of patients with different AAT serum levels. These results suggest that miR-320c can play a role in AAT regulation and could be a biomarker of inflammatory processes in pulmonary diseases.  相似文献   
33.
In this study, we investigated the mechanism of miR-200c-3p and SLC6A1 in regulating cell activity of clear cell renal cell carcinoma (CCRCC). The mRNA and miRNA expressions of tissue specimens were analyzed by CapitalBio Corporation (Beijing, China). The expression of SLC6A1 in CCRCC cells was examined through qRT-PCR and western blot. The migration and invasion ability of 786-O cells was testified by transwell assay after transfected. 786-O cell proliferation ability was detected by MTT assay. Dual luciferase reporter assay verified the association between SLC6A1 and miR-200c-3p. SLC6A1 was high expressed and miR-200c-3p was low expressed in CCRCC tissues and cells. Besides, lower SLC6A1 expression indicated longer survival time and higher survival rate. MiR-200c-3p could directly target at SLC6A1 and reduce its expression. MiR-200c-3p inhibited the proliferation, migration and invasion in 786-O cells by down-regulating SLC6A1 expression. The results suggested that the miR-200c-3p served as a suppressor for CCRCC via down-regulating SLC6A1.  相似文献   
34.
MicroRNAs (miRNAs) are 22- to 24-nucleotide, small, non-coding RNAs that bind to the 3′UTR of target genes to control gene expression. Consequently, their dysregulation contributes to many diseases, including diabetes and cancer. miR-22 is up-regulated in numerous metastatic cancers and recent studies have suggested a role for miR-22 in promoting stemness and metastasis. TIP60 is a lysine acetyl-transferase reported to be down-regulated in cancer but the molecular mechanism of this reduction is still unclear. In this study, we identify TIP60 as a target of miR-22. We show a negative correlation in the expression of TIP60 and miR-22 in breast cancer patients, and show that low levels of TIP60 and high levels of miR-22 are associated with poor overall survival. Furthermore, pathway analysis using high miR-22/low TIP60 and low miR-22/high TIP60 breast cancer patient datasets suggests association of TIP60/miR-22 with epithelial-mesenchymal transition (EMT), a key alteration in progression of cancer cells. We show that blocking endogenous miR-22 can restore TIP60 levels, which in turn decreases the migration and invasion capacity of metastatic breast cancer cell line. These results provide mechanistic insight into TIP60 regulation and evidence for the utility of the combination of TIP60 and miR-22 as prognostic indicator of breast cancer progression.  相似文献   
35.
MicroRNAs (miRNAs) regulate gene expression and are involved in cervical cancer. But the molecular mechanism is still unclear. Here, miRNA profile of cervical cancer was performed and demonstrated that miR-486-3p decreased in specimens of cervical cancer patients. In addition, our clinical data show that decreased miR-486-3p was associated with metastasis in cervical cancer patients. ECM1 was predicted and velified as a target gene of miR-486-3p. Overexpression of miR-486-3p inhibited cell growth and metastasis by targeting ECM1. In a conclusion, these findings suggest that miR-486-3p is a tumor suppressor miRNA and induction of miR-486-3p is a potential strategy to inhibit cervical cancer progression.  相似文献   
36.
目的研究去甲基化药物5-AZA对miR-34a和miR-34c在肝癌细胞中表达的影响及其抑制肝癌细胞糖酵解的分子机制。方法用real-time PCR法检测肝癌细胞系中miR-34a/c的表达以及糖酵解途径关键酶的表达;在肝癌细胞中过表达miR-34a、miR-34c或用5-AZA处理肝癌细胞,用乳酸检测试剂盒、葡萄糖检测试剂盒分析miR-34a/c及5-AZA对肝癌细胞BEL7402糖酵解的影响;设计拯救实验研究5-AZA、miR-34a/c与肝癌细胞糖酵解调控的关系。结果 5-AZA可以诱导BEL7402肝癌细胞内源性miR-34a、miR-34c的表达上调(P0.01);过表达miR-34a/c可以抑制糖酵解关键酶LDH-A的表达(P0.05);LDH-A是miR-34a/c的潜在靶基因;敲低miR-34a/c的表达可以降低5-AZA对肝癌细胞BEL7302糖酵解途径的抑制作用。结论 5-AZA通过诱导miR-34a/c表达上调,发挥抑制肝癌细胞代谢方式转换的功能。  相似文献   
37.
MiR-424是miR-16家族成员。近年研究表明miR-424与肿瘤的发生、发展及治疗预后密切相关。本文对miR-424在乳腺癌、宫颈癌、肺癌、肝癌及结直肠癌等多种肿瘤及白血病中的表达变化、作用及机制进行综述。研究发现miR-424的表达受多种因素的影响,miR-424可作为肿瘤诊断、分期、预后的生物标记物,可用于明确肿瘤范围,也可作为肿瘤的治疗靶物。  相似文献   
38.
Gastric cancer is one of the most common cancers in the world; taxol displayed modest efficacy as first-line chemotherapy for gastric cancer, conversely, it has limitations used alone. β-catenin is a multifunctional oncogenic protein and the elevation in expression and activity of β-catenin has been implicated in many cancers. Therefore, we assume that the inhibition of β-catenin can enhanced the efficacy of taxol. The purpose of this study was to investigate the inhibitory effect of miR-200a mimics, FH535 combined with taxol on proliferation and invasion of human gastric cancer cell lines SGC-7901 and BGC-823. In the current study, we identified that the combination of FH535 and miR-200a with taxol had potent growth-inhibitory and pro-apoptotic effects. Further, similar results were also observed in vivo, intratumoral injection of FH535, taxol and miR-200a mimics which also delayed tumor growth in nude mice harboring subcutaneous SGC-7901 xenografts. Collectively, miR-200a and FH535 can enhance the inhibitory effect of taxol on cell proliferation and moderate the invasion of human gastric cancer.  相似文献   
39.
40.
目的 探讨LncRNA Linc00152靶向调控miR-193a-3p对胃癌细胞增殖、侵袭和迁移的影响。方法 采用qRT-PCR法检测正常胃黏膜细胞GES-1及4种胃癌细胞(MGC803、BGC803、SGC7901、AGS)中Linc00152的表达水平。MGC-803细胞分为pcDNA3.1-GFP-Linc00152组、pcDNA3.1-GFP组;AGS细胞分为si-Linc00152组、si-NC组,分别转染相应的Linc00152过表达和抑制载体。qRT-PCR法检测Linc00152、细胞周期素D1(cyclin D1,CCND1)和miR-193a-3p基因的表达水平,CCK-8检测细胞的活性,细胞克隆试验检测细胞的克隆能力,Annexin VFITC/PI染色后采用流式细胞术检测转染细胞凋亡率,Transwell法检测细胞侵袭,荧光素酶报告试验检测Linc00152和miR-193a-3p靶向关系,Western blotting检测Bcl-2、Bax、CCND1、E-钙黏蛋白(E-cadherin)和波形蛋白(Vimentin)的蛋白表达水平。并将si-Linc00152组、si-NC组细胞接种裸鼠,观察裸鼠体质量和一般状态,处死后称重记录肿瘤体积、质量,qRT-PCR法测定肿瘤组织Linc00152、CCND1和miR-193a-3p的表达水平。结果 与GES-1细胞相比,胃癌细胞MGC803、BGC803、SGC7901、AGS中Linc00152的表达升高,其中Linc00152在胃癌MGC803细胞中表达较低,而在胃癌AGS细胞中的表达较高,选用胃癌MGC803、AGS细胞进行后续试验。与pcDNA3.1-GFP组相比,pcDNA3.1-GFP-Linc00152组细胞的活性显著升高,克隆能力增强,细胞凋亡减少,侵袭能力显著上升,CCND1、Bcl-2、波形蛋白的表达显著升高,miR-193a-3p和E-钙黏蛋白的表达显著降低。双荧光素酶报告基因系统检测结果显示,Linc00152可直接调控miR-193a-3p的转录活性,且Linc00152可显著上调MGC-803细胞CCND1蛋白表达。与si-NC组相比,si-Linc00152组的裸鼠体内的异种移植瘤体积和体质量显著下降,CCND1和Linc00152的表达显著下降,miR-193a-3p的表达显著上升。结论 Linc00152可靶向作用于miR-193a-3p促进胃癌细胞增殖、侵袭和迁移,其作用机制与细胞周期、上皮细胞间充质转化以及细胞凋亡有关。  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