全文获取类型
收费全文 | 441288篇 |
免费 | 39847篇 |
国内免费 | 16546篇 |
专业分类
耳鼻咽喉 | 2757篇 |
儿科学 | 10283篇 |
妇产科学 | 6188篇 |
基础医学 | 66438篇 |
口腔科学 | 8689篇 |
临床医学 | 35528篇 |
内科学 | 63438篇 |
皮肤病学 | 6367篇 |
神经病学 | 27742篇 |
特种医学 | 8449篇 |
外国民族医学 | 113篇 |
外科学 | 32702篇 |
综合类 | 61796篇 |
现状与发展 | 56篇 |
一般理论 | 28篇 |
预防医学 | 24705篇 |
眼科学 | 8641篇 |
药学 | 73530篇 |
72篇 | |
中国医学 | 18718篇 |
肿瘤学 | 41441篇 |
出版年
2024年 | 702篇 |
2023年 | 5663篇 |
2022年 | 8936篇 |
2021年 | 16129篇 |
2020年 | 14225篇 |
2019年 | 15420篇 |
2018年 | 15043篇 |
2017年 | 15579篇 |
2016年 | 15482篇 |
2015年 | 16882篇 |
2014年 | 25865篇 |
2013年 | 32408篇 |
2012年 | 26129篇 |
2011年 | 29710篇 |
2010年 | 25194篇 |
2009年 | 24051篇 |
2008年 | 23358篇 |
2007年 | 23256篇 |
2006年 | 21054篇 |
2005年 | 19115篇 |
2004年 | 16433篇 |
2003年 | 14379篇 |
2002年 | 11165篇 |
2001年 | 10208篇 |
2000年 | 8400篇 |
1999年 | 7528篇 |
1998年 | 5974篇 |
1997年 | 5408篇 |
1996年 | 5055篇 |
1995年 | 4547篇 |
1994年 | 4010篇 |
1993年 | 3456篇 |
1992年 | 3056篇 |
1991年 | 2669篇 |
1990年 | 2279篇 |
1989年 | 2024篇 |
1988年 | 1787篇 |
1987年 | 1477篇 |
1986年 | 1261篇 |
1985年 | 1832篇 |
1984年 | 1857篇 |
1983年 | 1263篇 |
1982年 | 1455篇 |
1981年 | 1153篇 |
1980年 | 967篇 |
1979年 | 798篇 |
1978年 | 667篇 |
1977年 | 533篇 |
1976年 | 544篇 |
1975年 | 385篇 |
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
21.
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
22.
23.
《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
24.
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
25.
Kevin Kyung Ho Choi Santosh Sanagapalli 《World journal of gastrointestinal oncology》2022,14(3):568-586
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
26.
Weina Cheng Yazhi Wang Jingxian Liu Xiaofei Li Ming Yu Cancan Duan Liu Liu Jianyong Zhang 《Journal of applied toxicology : JAT》2022,42(6):970-980
Cantharidin (CTD) is an effective antitumor agent. However, it exhibits significant hepatotoxicity, the mechanism of which remains unclear. In this study, biochemical and histopathological analyses complemented with ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS)-based targeted metabolomic analysis of bile acids (BAs) were employed to investigate CTD-induced hepatotoxicity in rats. Sixteen male and female Sprague–Dawley rats were randomly divided into two groups: control and CTD (1.0 mg/kg) groups. Serum and liver samples were collected after 28 days of intervention. Biochemical, histopathological, and BA metabolomic analyses were performed for all samples. Further, the key biomarkers of CTD-induced hepatotoxicity were identified via multivariate and metabolic pathway analyses. In addition, metabolite–gene–enzyme network and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used to identify the signaling pathways related to CTD-induced hepatotoxicity. The results revealed significantly increased levels of biochemical indices (alanine aminotransferase, aspartate aminotransferase, and total bile acid). Histopathological analysis revealed that the hepatocytes were damaged. Further, 20 endogenous BAs were quantitated via UHPLC-MS/MS, and multivariate and metabolic pathway analyses of BAs revealed that hyocholic acid, cholic acid, and chenodeoxycholic acid were the key biomarkers of CTD-induced hepatotoxicity. Meanwhile, primary and secondary BA biosynthesis and taurine and hypotaurine metabolism were found to be associated with the mechanism by which CTD induced hepatotoxicity in rats. This study provides useful insights for research on the mechanism of CTD-induced hepatotoxicity. 相似文献
27.
28.
目的 探讨滋肾育胎丸加减方预防抗磷脂抗体(ACA)阳性者不良妊娠结局的效果及机制研究。方法 选取2016年2月至2019年2月我院收治的89例ACA阳性,先兆性流产或有习惯性流产(RSA)史患者,将采用西医治疗的40例作为对照组,将采用西医联合滋肾育胎丸加减方治疗的49例作为观察组,比较两组中医证候疗效、中医证候积分、ACA-IgA、ACA-IgM、ACA-IgG、凝血指标[血小板聚集功能(PAF)、活化蛋白C(PC)、抗凝血酶(AT)、纤溶酶原激活抑制物-1(PAI-1)]、Th1/Th2细胞因子[干扰素γ(IFN-γ)、白介素-2(IL-2)、白介素-4(IL-4)、白介素-10(IL-10)]、妊娠结局、安全性。结果 治疗2周后检测ACA,观察组2例未降低,对照组11例未降低,观察组未降低患者占比低于对照组(P<0.05);观察组总有效率100.00%高于对照组85.00%(P<0.05);观察组治疗4周、7周后中医证候积分低于对照组(P<0.05);观察组治疗4周、7周后ACA-IgA、ACA-IgM、ACA-IgG低于对照组(P<0.05);观察组治疗4周、7周后PAF、PAI-1低于对照组,PC、AT高于对照组(P<0.05);观察组治疗4周、7周后IFN-γ、IL-2低于对照组,IL-4、IL-10高于对照组(P<0.05);观察组活产率95.92%高于对照组80.00%(P<0.05);组间不良反应总发生率比较,差异无统计学意义(P>0.05)。结论 动态监测ACA对滋肾育胎丸加减方精准应用具有指导意义,指导滋肾育胎丸加减方通过调理脏腑、气血、经络功能,改善先兆性流产或有RSA史患者临床症状及凝血因子指标,降低ACA水平,并可改善患者免疫耐受功能,提高胎儿活产率,且安全性高。 相似文献
29.
《Research in social & administrative pharmacy》2022,18(9):3694-3698
In this paper, we argue that understanding and addressing the problem of poor-quality medical products requires a more interdisciplinary approach than has been evident to date. While prospective studies based on rigorous standardized methodologies are the gold standard for measuring the prevalence of poor-quality medical products and understanding their distribution nationally and internationally, they should be complemented by social science research to unpack the complex set of social, economic, and governance factors that underlie these patterns. In the following sections, we discuss specific examples of prospective quality surveys and of social science studies, highlighting the value of cross-sector partnerships in driving high-quality, policy-relevant research in this area. 相似文献
30.
Guo-Quan Shi Huajun Zhu & Zhen-Guo Yan 《Communications In Computational Physics》2022,31(4):1215-1241
A priori subcell limiting approach is developed for high-order flux reconstruction/correction procedure via reconstruction (FR/CPR) methods on two-dimensional unstructured quadrilateral meshes. Firstly, a modified indicator based on
modal energy coefficients is proposed to detect troubled cells, where discontinuities
exist. Then, troubled cells are decomposed into nonuniform subcells and each subcell has one solution point. A second-order finite difference shock-capturing scheme
based on nonuniform nonlinear weighted (NNW) interpolation is constructed to perform the calculation on troubled cells while smooth cells are calculated by the CPR
method. Numerical investigations show that the proposed subcell limiting strategy on
unstructured quadrilateral meshes is robust in shock-capturing. 相似文献