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   28917篇
  免费   1780篇
  国内免费   1262篇
耳鼻咽喉   353篇
儿科学   554篇
妇产科学   476篇
基础医学   4937篇
口腔科学   387篇
临床医学   2528篇
内科学   4868篇
皮肤病学   296篇
神经病学   1373篇
特种医学   567篇
外科学   2904篇
综合类   4573篇
预防医学   2230篇
眼科学   292篇
药学   2305篇
  3篇
中国医学   399篇
肿瘤学   2914篇
  2024年   10篇
  2023年   178篇
  2022年   464篇
  2021年   587篇
  2020年   539篇
  2019年   421篇
  2018年   524篇
  2017年   562篇
  2016年   673篇
  2015年   731篇
  2014年   1378篇
  2013年   1573篇
  2012年   1730篇
  2011年   2016篇
  2010年   1670篇
  2009年   1723篇
  2008年   1971篇
  2007年   2117篇
  2006年   2059篇
  2005年   2005篇
  2004年   1582篇
  2003年   1483篇
  2002年   1169篇
  2001年   990篇
  2000年   862篇
  1999年   701篇
  1998年   494篇
  1997年   453篇
  1996年   246篇
  1995年   259篇
  1994年   176篇
  1993年   122篇
  1992年   74篇
  1991年   59篇
  1990年   59篇
  1989年   55篇
  1988年   46篇
  1987年   24篇
  1986年   26篇
  1985年   20篇
  1984年   14篇
  1983年   7篇
  1982年   14篇
  1981年   13篇
  1980年   10篇
  1979年   7篇
  1977年   8篇
  1973年   9篇
  1972年   7篇
  1971年   11篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
1.
《Survey of ophthalmology》2023,68(5):940-956
Congenital aniridia is a panocular disorder that is typically characterized by iris hypoplasia and aniridia-associated keratopathy (AAK). AAK results in the progressive loss of corneal transparency and thereby loss of vision. Currently, there is no approved therapy to delay or prevent its progression, and clinical management is challenging because of phenotypic variability and high risk of complications after interventions; however, new insights into the molecular pathogenesis of AAK may help improve its management. Here, we review the current understanding about the pathogenesis and management of AAK. We highlight the biological mechanisms involved in AAK development with the aim to develop future treatment options, including surgical, pharmacological, cell therapies, and gene therapies.  相似文献   
2.
Lipid nanoparticles (LNPs) are becoming popular as a means of delivering therapeutics, including those based on nucleic acids and mRNA. The mRNA-based coronavirus disease 2019 vaccines are perfect examples to highlight the role played by drug delivery systems in advancing human health. The fundamentals of LNPs for the delivery of nucleic acid- and mRNA-based therapeutics, are well established. Thus, future research on LNPs will focus on addressing the following: expanding the scope of drug delivery to different constituents of the human body, expanding the number of diseases that can be targeted, and studying the change in the pharmacokinetics of LNPs under physiological and pathological conditions. This review article provides an overview of recent advances aimed at expanding the application of LNPs, focusing on the pharmacokinetics and advantages of LNPs. In addition, analytical techniques, library construction and screening, rational design, active targeting, and applicability to gene editing therapy have also been discussed.  相似文献   
3.
4.
目的:探究养精种玉汤辅助体外受精-胚胎移植(IVF-ET)对排卵障碍性不孕患者的影响。方法:选取2016年12月至2017年3月邯郸市中心医院收治的排卵障碍性不孕患者82例作为研究对象,按照随机数字表法随机分为对照组与观察组,每组41例。对照组给予促性腺激素释放激素激动剂(Gn)+控制性促排卵+IVF-ET治疗,观察组在此基础上联合养精种玉汤治疗,至HCG日停止服用。治疗后统计2组Gn使用情况、取卵数及妊娠率;检测并比较HCG日2组子宫内膜容受性指标;比较2组妊娠结局及治疗期间相关不良反应发生情况。结果:观察组Gn使用天数及使用剂量均低于对照组,而妊娠率高于对照组(P<0.05或P<0.01);观察组子宫内膜类型为A型患者比例高于对照组,而子宫内膜类型为C型患者比例低于对照组(P<0.05或P<0.01);观察组子宫内膜厚度大于对照组,而子宫内膜动脉血流参数PI及RI均低于对照组(P<0.01);2组不良反应发生率差异无统计学意义(P>0.05),且治疗期间2组血清肝功能指标及血尿常规检测均未发现异常。结论:养精种玉汤辅助IVF-ET可有效增强排卵障碍性不孕患者子宫内膜容受性,提高患者妊娠率并改善其妊娠结局,具有良好的安全性。  相似文献   
5.
6.
背景与目的:在前列腺癌标准化疗方案中,多西他赛(docetaxel,DTX)引起的化疗耐药是引起患者死亡的重要原因之一,然而DTX引起的化疗耐药相关机制尚未知。探讨前列腺癌DTX耐药的作用机制。方法:收集2016年6月—2019年6月在武汉市第三医院进行化疗的40例患者,包括20例DTX耐药和20例DTX敏感患者。人前列腺癌细胞系PC-3在一系列逐渐增加的DTX浓度梯度处理下形成耐药株PC-3/DTX。采用实时荧光定量聚合酶链反应(real-time fluorescence quantitative polymerase chain reaction,RTFQ-PCR)检测miR-503和TLR4 mRNA的表达,采用蛋白质印迹法(Western blot)检测TLR4蛋白的水平,采用双荧光素酶报告基因检测miR-503和TLR4的相互作用,采用四甲基偶氮唑蓝(methyl thiazolyl tetrazolium,MTT)法检测细胞活力,采用流式细胞术检测细胞凋亡。结果:前列腺癌耐药患者组织和耐药细胞系中miR-503的表达较敏感组显著降低(P=0.013),而TLR4显著增加(P=0.005 6)。过表达miR-503显著抑制耐药细胞的增殖,促进凋亡,同时抑制耐药相关蛋白MDR-1的表达,而过表达TLR4则促进细胞的增殖,抑制凋亡,促进耐药相关蛋白MDR-1的表达。结论:miR-503通过靶向调控TLR4的表达影响前列腺癌的DTX耐药。  相似文献   
7.
目的探讨体外转染细胞周期素A2(Cyclin A2)基因对原代大鼠心肌细胞增殖的影响,为心脏再生提供细胞学依据。方法 SD乳鼠12只,分离、培养、鉴定原代乳鼠心肌细胞并分为3组,实验组:转染带有强化绿色荧光蛋白(GFP)和Cyclin A2基因的重组腺病毒(Ad-Cyclin A2-GFP);空病毒组:转染不含目的基因带有GFP的重组腺病毒(Ad-Null-GFP);阴性对照组:未做转染处理,仅加入等量的培养基。利用GFP示踪技术,评估原代心肌细胞转染效率;转染后的细胞继续体外培养3~5d,利用免疫荧光技术分别检测Cyclin A2、磷酸化组蛋白H3(H3P)、心肌肌钙蛋白-T(c Tn T)。结果 1.荧光GFP示踪表明原代心肌细胞的转染效率高达(97±0.74)%;2.免疫荧光标记显示,空病毒组和对照组结果相似;心肌细胞特异性标记蛋白c Tn T分布于细胞质,原代心肌细胞纯度高达(95±0.62)%;心肌细胞Cyclin A2主要在胞核内聚集,少数分布于细胞质。H3P为核蛋白在细胞核内分布。3.转染Cyclin A2后,实验组H3P阳性率明显高于空病毒组和对照组,差异具有统计学意义(P0.05);实验组可见大量多核细胞,以双核为主,伴少量3核细胞。结论腺病毒作为转染载体对原代心肌细胞有很好的侵染效率;Cyclin A2超表达促进原代心肌细胞形成双核。  相似文献   
8.
9.
Autoimmune thyroid diseases (AITD) and Type 1 diabetes (T1D) frequently occur in the same individual pointing to a strong shared genetic susceptibility. Indeed, the co-occurrence of T1D and AITD in the same individual is classified as a variant of the autoimmune polyglandular syndrome type 3 (designated APS3v). Our aim was to identify new genes and mechanisms causing the co-occurrence of T1D + AITD (APS3v) in the same individual using a genome-wide approach. For our discovery set we analyzed 346 Caucasian APS3v patients and 727 gender and ethnicity matched healthy controls. Genotyping was performed using the Illumina Human660W-Quad.v1. The replication set included 185 APS3v patients and 340 controls. Association analyses were performed using the PLINK program, and pathway analyses were performed using the MAGENTA software. We identified multiple signals within the HLA region and conditioning studies suggested that a few of them contributed independently to the strong association of the HLA locus with APS3v. Outside the HLA region, variants in GPR103, a gene not suggested by previous studies of APS3v, T1D, or AITD, showed genome-wide significance (p < 5 × 10−8). In addition, a locus on 1p13 containing the PTPN22 gene showed genome-wide significant associations. Pathway analysis demonstrated that cell cycle, B-cell development, CD40, and CTLA-4 signaling were the major pathways contributing to the pathogenesis of APS3v. These findings suggest that complex mechanisms involving T-cell and B-cell pathways are involved in the strong genetic association between AITD and T1D.  相似文献   
10.
PurposeWe previously demonstrated that the functional inactivation of DAL-1 and TOB1 promotes an aggressive phenotype in gastric cancer cells, but the links between both genes and the survival of patients with gastric cancer are unknown. Here, we investigated the correlations of the expression levels of DAL-1 and TOB1 with the progression of gastric cancer.MethodsA total of 270 patients who underwent resectable gastrectomy were included. The expression of DAL-1 and TOB1 was detected by immunohistochemistry.ResultsLow expression of DAL-1 in cancer tissue was significantly associated with tumor site (p < 0.05), histological grade (p < 0.01), depth of invasion (p < 0.05), lymph node metastasis status (p < 0.05), Lauren classification (p < 0.001), and clinical stage (p < 0.01). A lower level of TOB1 was observed in gastric cancer patients with diffuse type disease compared to patients with either intestinal or mixed type disease (p < 0.001). Additionally, Spearman’s correlation analysis revealed that decreased expression of DAL-1 was positively correlated with low TOB1 expression (r=0.304, p < 0.001). The survival analysis showed that low levels of DAL-1 and TOB1 were significantly associated with poor survival of gastric cancer patients (p <0.001 and p < 0.05, respectively).ConclusionThe downregulation of DAL-1 and TOB1 expression is associated with shorter survival of gastric cancer patients. Hence, DAL-1 and TOB1 may be considered potential novel markers for predicting the outcomes of patients with gastric cancer.  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