全文获取类型
收费全文 | 200546篇 |
免费 | 15243篇 |
国内免费 | 4530篇 |
专业分类
耳鼻咽喉 | 1702篇 |
儿科学 | 2615篇 |
妇产科学 | 3074篇 |
基础医学 | 24206篇 |
口腔科学 | 3541篇 |
临床医学 | 16889篇 |
内科学 | 23529篇 |
皮肤病学 | 2197篇 |
神经病学 | 12487篇 |
特种医学 | 16623篇 |
外国民族医学 | 1篇 |
外科学 | 15971篇 |
综合类 | 26814篇 |
现状与发展 | 21篇 |
一般理论 | 8篇 |
预防医学 | 15061篇 |
眼科学 | 3256篇 |
药学 | 26031篇 |
57篇 | |
中国医学 | 12725篇 |
肿瘤学 | 13511篇 |
出版年
2024年 | 253篇 |
2023年 | 2256篇 |
2022年 | 3537篇 |
2021年 | 7952篇 |
2020年 | 6512篇 |
2019年 | 6224篇 |
2018年 | 6489篇 |
2017年 | 7236篇 |
2016年 | 7514篇 |
2015年 | 7001篇 |
2014年 | 8648篇 |
2013年 | 12202篇 |
2012年 | 10639篇 |
2011年 | 12690篇 |
2010年 | 8424篇 |
2009年 | 8637篇 |
2008年 | 10101篇 |
2007年 | 10880篇 |
2006年 | 10256篇 |
2005年 | 9394篇 |
2004年 | 8000篇 |
2003年 | 7133篇 |
2002年 | 5656篇 |
2001年 | 5096篇 |
2000年 | 4177篇 |
1999年 | 3525篇 |
1998年 | 2795篇 |
1997年 | 2832篇 |
1996年 | 2516篇 |
1995年 | 2219篇 |
1994年 | 2132篇 |
1993年 | 1765篇 |
1992年 | 1617篇 |
1991年 | 1505篇 |
1990年 | 1302篇 |
1989年 | 1072篇 |
1988年 | 1033篇 |
1987年 | 931篇 |
1986年 | 859篇 |
1985年 | 1243篇 |
1984年 | 998篇 |
1983年 | 752篇 |
1982年 | 775篇 |
1981年 | 642篇 |
1980年 | 620篇 |
1979年 | 496篇 |
1978年 | 319篇 |
1977年 | 270篇 |
1976年 | 262篇 |
1975年 | 189篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
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
12.
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
13.
《Vaccine》2022,40(16):2370-2378
Porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae (M. hyopneumoniae, Mhp) are two of the most common pathogens involved in the porcine respiratory disease complex (PRDC) resulting in significant economic losses worldwide. Vaccination is the most effective approach to disease prevention. Since PRRSV and Mhp co-infections are very common, an efficient dual vaccine against these pathogens is required for the global swine industry. Compared with traditional vaccines, multi-epitope vaccines have several advantages, they are comparatively easy to produce and construct, are chemically stable, and do not have an infectious potential. In this study, to develop a safe and effective vaccine, B cell and T cell epitopes of PRRSV-GP5, PRRSV-M, Mhp-P46, and Mhp-P65 protein had been screened to construct a recombinant epitope protein rEP-PM that has good hydrophilicity, strong antigenicity, and high surface accessibility, and each epitope is independent and complete. After immunization in mice, rEP-PM could induce the production of high levels of antibodies, and it had good immunoreactivity with anti-rEP-PM, anti-PRRSV, and anti-Mhp antibodies. The anti-rEP-PM antibody specifically recognizes proteins from PRRSV and Mhp. Moreover, rEP-PM induced a Th1-dominant cellular immune response in mice. Our results showed that the rEP-PM protein could be a potential candidate for the development of a safe and effective multi-epitope peptide combined vaccine to control PRRSV and Mhp infections. 相似文献
14.
15.
16.
17.
Xiying Fan Glen A. Bjerke Kent Riemondy Li Wang Rui Yi 《Molecular carcinogenesis》2019,58(12):2241-2253
MicroRNAs (miRNAs) play important roles in prostate cancer development. However, it remains unclear how individual miRNAs contribute to the initiation and progression of prostate cancer. Here we show that a basal layer‐enriched miRNA is required for prostate tumorigenesis. We identify miR‐205 as the most highly expressed miRNA and enriched in the basal cells of the prostate. Although miR‐205 is not required for normal prostate development and homeostasis, genetic deletion of miR‐205 in a Pten null tumor model significantly compromises tumor progression and does not promote metastasis. In Pten null basal cells, loss of miR‐205 attenuates pAkt levels and promotes cellular senescence. Furthermore, although overexpression of miR‐205 in prostate cancer cells with luminal phenotypes inhibits cell growth in both human and mouse, miR‐205 has a minimal effect on the growth of a normal human prostate cell line. Taken together, we have provided genetic evidence for a requirement of miR‐205 in the progression of Pten null‐induced prostate cancer. 相似文献
18.
This study is focussed on micro-encapsulation of essential oils in polylactic acid (PLA) and a poly(methyl methacrylate) (PMMA) matrix as well as blends of the same. Microspheres were prepared by the solvent evaporation technique and characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR). The encapsulation efficiencies and release profiles of the essential oils were studied by gas chromatography mass spectrometry (GC-MS) and head-space solid-phase microextraction GC-MS, respectively. Furthermore, the microspheres were tested for antibacterial activity against both Gram-negative and Gram-positive bacterial strains.
The results showed that the microspheres compositions (PLA/PMMA ratio) have significant effect on their characteristics. The process adopted for preparing the microspheres promoted formation of spherical particles at the sizes of 1.5–9.5?µm. The highest encapsulation efficiency of the prepared microspheres was observed in systems consisting of linalool (81.10?±?10.0?wt. % for PLA system and 76.0?±?3.3?wt. % for PMMA system). Confirmation was also made that the release rate of the microspheres was affected by the size of the same. 相似文献
19.
20.
目的探讨继发性附件扭转的CT特征及其诊断效能,构建继发性附件扭转的评分系统。资料与方法收集经手术证实的伴有附件肿物的继发性附件扭转患者37例,以及伴有腹痛、附件肿物的对照组患者34例,分析继发性附件扭转的CT特征,采用受试者工作特征(ROC)曲线评价其诊断效能,构建继发性附件扭转的综合评分系统(AT-CI)。结果与对照组比较,继发性附件扭转以下CT特征发生率较高,包括肿物壁偏心性增厚(X^2=4.41,P<0.05)、附件出血(X^2=12.68,P<0.001)、肿物-子宫之间团块状结构(X^2=13.62,P<0.001)、旋涡征(X^2=10.71,P<0.05)、附件周围脂肪模糊/腹水(X^2=5.82,P<0.05)。其中肿物-子宫之间团块状结构敏感度及诊断价值最高,为81.1%(ROC曲线下面积0.71),旋涡征特异度最高,为91.2%。ATCI诊断效能优于任意单一CT特征(ROC曲线下面积0.83),评分0~2分继发性附件扭转可能性小,3~4分怀疑继发性附件扭转,评分>4分,则高度怀疑继发性附件扭转且特异度为100%。结论继发性附件扭转具有典型的CT特征,包括肿物壁偏心性增厚、附件出血、肿物-子宫之间团块状结构、旋涡征、肿物周围脂肪模糊/腹水。AT-CI是综合了继发性附件扭转全部CT特征的实用评分系统,提高了继发性附件扭转的诊断准确性。 相似文献