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   224882篇
  免费   17547篇
  国内免费   7051篇
耳鼻咽喉   1338篇
儿科学   7749篇
妇产科学   1753篇
基础医学   19869篇
口腔科学   3793篇
临床医学   23712篇
内科学   56169篇
皮肤病学   2815篇
神经病学   26608篇
特种医学   6544篇
外国民族医学   4篇
外科学   17277篇
综合类   30450篇
现状与发展   31篇
一般理论   11篇
预防医学   18218篇
眼科学   2726篇
药学   15685篇
  197篇
中国医学   10359篇
肿瘤学   4172篇
  2024年   452篇
  2023年   4552篇
  2022年   6959篇
  2021年   12340篇
  2020年   11534篇
  2019年   9310篇
  2018年   9145篇
  2017年   8672篇
  2016年   8859篇
  2015年   8428篇
  2014年   15982篇
  2013年   17720篇
  2012年   13533篇
  2011年   13927篇
  2010年   10944篇
  2009年   10461篇
  2008年   10470篇
  2007年   10122篇
  2006年   9012篇
  2005年   7443篇
  2004年   6317篇
  2003年   5440篇
  2002年   4583篇
  2001年   3964篇
  2000年   3308篇
  1999年   2828篇
  1998年   2708篇
  1997年   2386篇
  1996年   2141篇
  1995年   1939篇
  1994年   1784篇
  1993年   1518篇
  1992年   1453篇
  1991年   1279篇
  1990年   1011篇
  1989年   860篇
  1988年   805篇
  1987年   732篇
  1986年   634篇
  1985年   772篇
  1984年   630篇
  1983年   399篇
  1982年   464篇
  1981年   390篇
  1980年   288篇
  1979年   253篇
  1978年   190篇
  1977年   169篇
  1976年   137篇
  1975年   56篇
排序方式: 共有10000条查询结果,搜索用时 484 毫秒
21.
胆囊切除术是公认的胆囊良性疾病的治愈手段,国内外学术界对于手术适应证和手术时机已有明确共识。近年来,“保胆手术”治疗胆囊良性疾病颇受热议,一些医生将“保护胆囊”的学术观点等同于“保留胆囊”的手术技术,这种误解可能导致病人出现差异性的预后。因此,临床医师应明晰“保护胆囊”理念与“保胆手术”的差别,对胆囊良性疾病的诊疗原则有正确的理解和应用。  相似文献   
22.
Inflammatory bowel disease (IBD) is a chronic disease that requires chronic treatment throughout the evolution of the disease, with a complex physiopathology that entails great challenges for the development of new and specific treatments for ulcerative colitis and Crohn´s disease. The anti-tumor necrosis factor alpha therapy has impacted the clinical course of IBD in those patients who do not respond to conventional treatment, so there is a need to develop new therapies and markers of treatment response. Various pathways involved in the development of the disease are known and the new therapies have focused on blocking the inflammatory process at the gastrointestinal level by oral, intravenous, subcutaneous, and topical route. All these new therapies can lead to more personalized treatments with higher success rates and fewer relapses. These treatments have not only focused on clinical remission, but also on achieving macroscopic changes at the endoscopic level and microscopic changes by achieving mucosal healing. These treatments are mainly based on modifying signaling pathways, by blocking receptors or ligands, reducing cell migration and maintaining the integrity of the epithelial barrier. Therefore, this review presents the efficacy and safety of the new treatments that are currently under study and the advances that have been made in this area in recent years.  相似文献   
23.
24.
25.
目的 调查社区老年人常见的14种慢性病共病情况及不良生活方式共存现象。 方法 采用方便抽样的方法抽取厦门市社区906例老年人群为研究对象,使用自设问卷调查研究对象的慢病共存及不良方式共存现象,使用检验和多因素logistic回归方法进行分析。结果 共纳入906例老年人,慢性病患病率为79.5%,老年人慢性病共病患病率为58.9%。主要的不良生活方式是BMI异常(46.8%)、饮酒(40.5%)、睡眠时间少(37.9%)、缺乏锻炼(35.2%)、吸烟(32.8%)等。多因素logistic回归分析显示,女性(OR=2.232,95%CI:1.474~3.380,P<0.001)、高龄(OR=2.038,95%CI:1.234~3.365,P=0.001)、有慢性病家族史(OR=2.854,95%CI:1.943~4.194,P<0.001)、肥胖(OR=2.571,95%CI:1.096~6.033,P=0.030)、饮酒(OR=3.582,95%CI:2.531~5.071,P<0.001)、吸烟(OR=1.789,95%CI:1.172~2.732,P=0.007)、嗜盐(OR=1.818,95%CI:1.170~2.823,P=0.008)、嗜油(OR=2.023,95%CI:1.153~3.550,P=0.010)、睡眠质量差(OR=2.091,95%CI:1.360~3.215,P=0.001)的老年人,慢性病共病的比例高。 结论 厦门市社区老年人慢性病共病和不良生活方式共存现象严重。肥胖、饮酒、吸烟、嗜盐、嗜油、睡眠质量差等行为生活方式是慢性病重要的可干预因素,社区工作者应提高社区居民对健康生活方式重要性的认识,促使其主动改变不良生活方式并长期坚持健康的生活方式,以降低其慢性病的发病风险,减少其伤残程度,提高生活质量。  相似文献   
26.
Major depressive disorder and other neuropsychiatric disorders are often managed with long-term use of antidepressant medication. Fluoxetine, an SSRI antidepressant, is widely used as a first-line treatment for neuropsychiatric disorders. However, fluoxetine has also been shown to increase the risk of metabolic diseases such as non-alcoholic fatty liver disease. Fluoxetine has been shown to increase hepatic lipid accumulation in vivo and in vitro. In addition, fluoxetine has been shown to alter the production of prostaglandins which have also been implicated in the development of non-alcoholic fatty liver disease. The goal of this study was to assess the effect of fluoxetine exposure on the prostaglandin biosynthetic pathway and lipid accumulation in a hepatic cell line (H4-II-E-C3 cells). Fluoxetine treatment increased mRNA expression of prostaglandin biosynthetic enzymes (Ptgs1, Ptgs2, and Ptgds), PPAR gamma (Pparg), and PPAR gamma downstream targets involved in fatty acid uptake (Cd36, Fatp2, and Fatp5) as well as production of 15-deoxy-Δ12,14PGJ2 a PPAR gamma ligand. The effects of fluoxetine to induce lipid accumulation were attenuated with a PTGS1 specific inhibitor (SC-560), whereas inhibition of PTGS2 had no effect. Moreover, SC-560 attenuated 15-deoxy-Δ12,14PGJ2 production and expression of PPAR gamma downstream target genes. Taken together these results suggest that fluoxetine-induced lipid abnormalities appear to be mediated via PTGS1 and its downstream product 15d-PGJ2 and suggest a novel therapeutic target to prevent some of the adverse effects of fluoxetine treatment.  相似文献   
27.
目的 基于文本挖掘技术和生物医学数据库对新型冠状病毒肺炎(COVID-19)相关文献进行数据挖掘分析,探究COVID-19及其主要症状发热、咳嗽、呼吸障碍相关基因靶点,筛选潜在有效的化学药和中药。方法 使用GenCLiP 3网站获取COVID-19和其主要症状咳嗽、发热、呼吸障碍共4个关键词的共有靶点,在METASCAPE数据库中对其进行基因本体(GO)和通路富集分析,再利用String数据库和Cytoscape软件构建共有靶点的蛋白质相互作用网络,筛选获得核心基因,运用DGIdb数据库、SymMap数据库针对核心基因进行中西医治疗药物预测。结果 获得COVID-19及其主要症状共有基因靶点28个,其中有IL2、IL1B、CCL2等核心基因16个,使用DGIdb数据库筛选获得与16个关键靶点相互作用的化学药包括沙利度胺、来氟米特、环孢素等28种,中药包括虎杖、黄芪、芦荟等70味。结论 COVID-19及其主要症状的病理机制可能和CD4、KNG1、VEGFA等28个共有基因相关,可能通过介导TNF、IL-17等信号通路参与COVID-19病理过程。潜在有效药物可能通过作用相关靶点通路起到治疗COVID-19的作用。  相似文献   
28.
阿尔茨海默病是一种进行性且不可逆转的神经系统疾病,由于视网膜和中枢神经系统有相似的胚胎起源和生理特征,眼科检查可提供简单无创的诊断方法。光学相干断层扫描技术(OCT)能够精确地测量视网膜各个组织层面的厚度,以评估视网膜的退行性改变,光学相干断层扫描血管成像(OCTA)可以提供高分辨率三维成像,从而更直观地检测视网膜血管的变化,间接地反映脑神经元和血管的病理特征。就OCT测量视网膜厚度及OCTA测量视网膜血流变化在阿尔茨海默病诊断中的研究进展进行综述。  相似文献   
29.
30.
Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC). Progression to cancer typically occurs in a stepwise fashion through worsening dysplasia and ultimately, invasive neoplasia. Established EAC with deep involvement of the esophageal wall and/or metastatic disease is invariably associated with poor long-term survival rates. This guides the rationale of surveillance of Barrett’s in an attempt to treat lesions at an earlier, and potentially curative stage. The last two decades have seen a paradigm shift in management of Barrett’s with rapid expansion in the role of endoscopic eradication therapy (EET) for management of dysplastic and early neoplastic BE, and there have been substantial changes to international consensus guidelines for management of early BE based on evolving evidence. This review aims to assist the physician in the therapeutic decision-making process with patients by comprehensive review and summary of literature surrounding natural history of Barrett’s by histological stage, and the effectiveness of interventions in attenuating the risk posed by its natural history. Key findings were as follows. Non-dysplastic Barrett’s is associated with extremely low risk of progression, and interventions cannot be justified. The annual risk of cancer progression in low grade dysplasia is between 1%-3%; EET can be offered though evidence for its benefit remains confined to highly select settings. High-grade dysplasia progresses to cancer in 5%-10% per year; EET is similarly effective to and less morbid than surgery and should be routinely performed for this indication. Risk of nodal metastases in intramucosal cancer is 2%-4%, which is comparable to operative mortality rate, so EET is usually preferred. Submucosal cancer is associated with nodal metastases in 14%-41% hence surgery remains standard of care, except for select situations.  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