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   7122篇
  免费   418篇
  国内免费   293篇
耳鼻咽喉   21篇
儿科学   54篇
妇产科学   104篇
基础医学   1393篇
口腔科学   97篇
临床医学   474篇
内科学   1067篇
皮肤病学   81篇
神经病学   1051篇
特种医学   106篇
外科学   404篇
综合类   948篇
预防医学   334篇
眼科学   45篇
药学   600篇
中国医学   412篇
肿瘤学   642篇
  2024年   6篇
  2023年   101篇
  2022年   200篇
  2021年   176篇
  2020年   103篇
  2019年   117篇
  2018年   117篇
  2017年   137篇
  2016年   146篇
  2015年   142篇
  2014年   253篇
  2013年   315篇
  2012年   323篇
  2011年   390篇
  2010年   388篇
  2009年   383篇
  2008年   443篇
  2007年   421篇
  2006年   411篇
  2005年   347篇
  2004年   329篇
  2003年   323篇
  2002年   291篇
  2001年   281篇
  2000年   231篇
  1999年   198篇
  1998年   183篇
  1997年   162篇
  1996年   162篇
  1995年   151篇
  1994年   123篇
  1993年   86篇
  1992年   82篇
  1991年   59篇
  1990年   49篇
  1989年   41篇
  1988年   23篇
  1987年   22篇
  1986年   20篇
  1985年   33篇
  1984年   21篇
  1983年   3篇
  1982年   9篇
  1981年   11篇
  1980年   6篇
  1979年   6篇
  1978年   6篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
排序方式: 共有7833条查询结果,搜索用时 31 毫秒
1.
2.
《Vaccine》2022,40(32):4296-4300
Advanced computational methodologies suggested SARS-CoV-2, nonstructural proteins ORF1AB, ORF3a, as the source of immunodominant peptides for T cell presentation. T cell immunity is long-lasting and compatible with COVID-19 pathology. Based on the supporting clinical data, nonstructural SARS-CoV-2 protein vaccines could provide global immunity against COVID-19.  相似文献   
3.
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   
4.
Over 36 million people worldwide are infected with HIV. Antiretroviral therapy (ART) has proven to be highly effective to prevent HIV-1 transmission, clinical progression and death. Despite this success, the number of HIV-1 infected individuals continues increasing and ART should be taken for life. Therefore, there are two main priorities: the development of preventive vaccines to protect from HIV acquisition and achieve an efficient control of HIV infection in the absence of ART (functional cure). In this sense, in the last few years, there has been a broad interest in new and innovative approaches such as mRNA-based vaccines. RNA-based immunogens represent a promising alternative to conventional vaccines because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration. Some mRNA-based vaccines platforms against infectious diseases have demonstrated encouraging results in animal models and humans. However, their application is still limited because the instability and inefficient in vivo delivery of mRNA. Immunogens, design, immunogenicity, chemical modifications on the molecule or the vaccine delivery methods are all crucial interventions for improvement. In this review we, will present the current knowledge and challenges in this research field. mRNA vaccines hold great promises as part of a combined strategy, for achieving HIV functional cure.  相似文献   
5.
6.
目的 探讨类风湿关节炎患者外周血miR-150-5p、细胞因子信号抑制因子1(suppressor of cytokine signaling 1,SOCS1)mRNA的表达及对类风湿关节炎(Rheumatoid Arthritis,RA)疾病诊断、中医证型判断的意义。方法 纳入符合诊断标准的RA患者57例及健康对照组19例,根据《22个专业95个病种中医诊疗方案》有关RA的中医证候诊断标准,判断RA的中医证型。qPCR检测RA患者及健康对照组miR-150-5p、SOCS1mRNA的相对表达水平,同时检测血常规、肝功能、肾功能等常规指标。双荧光素酶分析方法判断两者是否存在靶向关系。统计分析miR-150-5p、SOCS1 mRNA对RA疾病的诊断意义及其与中医证型的相关性。结果 RA患者外周血miR-150-5p的相对表达水平下调,低于正常人群(t = -19.019,P < 0.05);其表达水平随疾病活动度升高,有下降趋势;患者外周血SOCS1 mRNA的相对表达水平上调,低于正常人群(t = 5.333,P < 0.05);其表达水平随疾病活动度升高,有上升趋势。MiR-150-5p与SOCS1 mRNA有靶向结合关系(P < 0.05)。通过AUC曲线比较,miR-150-5p的相对表达水平区分RA的敏感性及特异性分别为98.1%、92.1%(AUC = 0.972,P < 0.05);SOCS1 mRNA的相对表达水平无法区分RA(AUC = 0.472,P > 0.05)。RA患者中miR-150-5p的相对表达水平低于3.06,RA患者风湿痹阻证、寒湿痹阻证的相对风险分别为8.33、250.00(P < 0.05)。结论 miR-150-5p、SOCS1 mRNA在RA患者中有差异性表达,且有靶向结合关系。miR-150-5p可能是RA的疾病诊断及中医风湿痹阻证、寒湿痹阻证证型诊断的潜在生物标志物。  相似文献   
7.
8.
补肾排毒合剂治疗慢性肾衰竭营养不良60例临床观察   总被引:1,自引:0,他引:1  
目的:观察补肾排毒合剂治疗慢性肾衰竭营养不良的疗效.方法:90例慢性肾衰竭营养不良患者随机分为治疗组60例和对照组30例,并设健康对照组30例.治疗组和对照组在综合治疗的基础上,治疗组加用补肾排毒合剂,对照组加用爱西特和百令胶囊.比较两组肾功能、营养状态和血浆瘦素、神经肽Y的变化.结果:治疗组治疗后BUN、Scr明显降低,与治疗前及对照组相比均有统计学差异(P<0.05).治疗组营养状态好转,与治疗前及对照组相比均有统计学差异(P<0.05).两组慢性肾衰竭营养不良患者治疗前Leptin、NPY水平均高于健康组(P<0.05),治疗后治疗组Leptin、NPY较治疗前下降,有统计学意义(P<0.05),但与对照组相比无统计学差异(P>0.05).结论:补肾排毒合剂治疗慢性肾衰竭营养不良疗效明显,可降低BUN、Scr,改善营养不良状态.  相似文献   
9.
目的:从分子水平研究抗纤Ⅰ号方剂治疗肝纤维化的作用机理。方法:利用CCl4、高脂饮食和乙醇等综合因素制造大鼠肝纤维化模型。模型成功后将大鼠随机分为肝纤维化模型组、中药和西药治疗组。分别治疗42 d后,检测各组大鼠肝组织病理学变化、血清肝功能和肝纤维化指标、免疫组化检测肝组织Ⅰ、Ⅲ型胶原的变化、半定量PCR检测肝组织MMP1、TIMP-1 mRNA表达量的变化。结果:中药组肝组织病理学变化明显优于模型组和西药治疗组;血清肝功能指标中药治疗组ALT和AST(108±24,142±23)显著低于模型组(242±34,248±20)和西药对照组(123±39,216±25,P<0.05);肝纤维化指标中药治疗组HA和LN(270±79,62±10)显著低于模型组(769±67,109±26)和西药对照组(346±62,79±13,P<0.05);中药治疗后能够明显减少肝组织Ⅰ、Ⅲ型胶原以及TIMP-1 mRNA的表达量,但MMP1的表达量无显著差异。结论:抗纤Ⅰ号通过下调TIMP-1mRNA减弱对MMP1的抑制作用,使Ⅰ、Ⅲ型胶原的降解增强而使肝纤维化逆转。  相似文献   
10.
Nerve growth factor (NGF) and NGF receptors were measured in cortex and hippocampus of rats treated with drugs affecting cholinergic neurotransmission. High (Kd= 0.045nM) and low (Kd= 21nM) affinity125I-NGF binding sites were present in both cortical and hippocampal membranes with hippocampus containing higher numbers of both sites than cortex. Chronic treatment of rats with the muscarinic receptor antagonist scopolamine (5 mg/kg, twice daily) decreased the density of high- and low-affinity sites by 50–90% in cortical and hippocampal membranes. These changes were seen after 7 days, but not 3 days, of scopolamine treatment. Chronic infusion of physostigmine (1 mg/kg/day) using minipumps increased the number of high- and low-affinity sites in cortex 3- and 6-fold, respectively. The changes in receptor-binding parameters induced by physostigmine were transient as they were evident after 3 days of treatment, but returned to control levels after 7 days. NGF content in cortex and hippocampus was reduced by about 50% following 7, but not 3, days of chronic physostigmine infusion. In contrast, scopolamine treatment failed to change NGF levels in the cholinergic neuronal target regions but it decreased NGF content in the septal area. The content of NGF mRNA in the cortex measured by Northern blot analysis failed to change following either scopolamine or physostigmine treatment. The results suggest that levels of NGF and NGF receptors in the target regions of cholinergic neurons are regulated by the extent of cholinergic neurotransmitter activity.  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