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   132073篇
  免费   13372篇
  国内免费   7534篇
耳鼻咽喉   823篇
儿科学   1073篇
妇产科学   1637篇
基础医学   31700篇
口腔科学   3258篇
临床医学   9077篇
内科学   19794篇
皮肤病学   2021篇
神经病学   8351篇
特种医学   2633篇
外国民族医学   80篇
外科学   12247篇
综合类   20856篇
现状与发展   24篇
一般理论   2篇
预防医学   3560篇
眼科学   2860篇
药学   12301篇
  44篇
中国医学   4390篇
肿瘤学   16248篇
  2024年   264篇
  2023年   1692篇
  2022年   3345篇
  2021年   4563篇
  2020年   4219篇
  2019年   3677篇
  2018年   3658篇
  2017年   4367篇
  2016年   5113篇
  2015年   5583篇
  2014年   8402篇
  2013年   10044篇
  2012年   7881篇
  2011年   8980篇
  2010年   7218篇
  2009年   6891篇
  2008年   7273篇
  2007年   7452篇
  2006年   6703篇
  2005年   5903篇
  2004年   4908篇
  2003年   4026篇
  2002年   3219篇
  2001年   2822篇
  2000年   2486篇
  1999年   2095篇
  1998年   1990篇
  1997年   1827篇
  1996年   1656篇
  1995年   1722篇
  1994年   1536篇
  1993年   1296篇
  1992年   1059篇
  1991年   1034篇
  1990年   872篇
  1989年   844篇
  1988年   732篇
  1987年   631篇
  1986年   511篇
  1985年   751篇
  1984年   676篇
  1983年   486篇
  1982年   578篇
  1981年   445篇
  1980年   388篇
  1979年   334篇
  1978年   225篇
  1977年   180篇
  1976年   163篇
  1975年   65篇
排序方式: 共有10000条查询结果,搜索用时 24 毫秒
71.
ABSTRACT

Purpose

New instrument-based techniques for anterior chamber (AC) cell counting can offer automation and objectivity above clinician assessment. This review aims to identify such instruments and its correlation with clinician estimates.  相似文献   
72.
《Molecular immunology》2015,63(2):296-304
Regulatory B cells (Bregs) are defined by their ability to restrain inflammatory responses both in vivo and in vitro. Interleukin 10 (IL-10) production by Bregs is thought to be central to their ability to regulate inflammation, largely due to IL-10s’ ability to suppress pro-inflammatory cytokine production by effector lymphocytes and to maintain the differentiation of regulatory T cells (Tregs). However, with an increase in available published data, it has become evident that Bregs utilize a number of suppressive mechanisms in order to alter the activation of a variety of different lymphocytes. Here, we summarize the multiplicity of cellular targets of Breg-mediated suppression and describe the mechanisms employed by Bregs to suppress chronic inflammatory responses.  相似文献   
73.
ObjectiveProgrammed death ligand 1 (PD-L1) has been reported to be connected to prognosis in individuals with malignant pleural mesothelioma (MPM), although there is no consensus based on data from previous studies. Accordingly, this quantitative meta-analysis investigated prognostic and clinicopathological utility of PD-L1 in patients with MPM.MethodsA comprehensive search of the PubMed, Web of Science, Embase, and Cochrane Library databases for articles published up to October 4, 2019 was performed. Studies using immunohistochemical techniques to detect/quantify the expression of PD-L1 in MPM tissue were enrolled in the analysis. The combined hazard ratio (HR) and corresponding 95% confidence interval (CI) was applied to assess the association between PD-L1 expression and overall survival (OS).ResultsA total of 11 studies comprising 1606 patients was included in the present meta-analysis. For OS, pooled data revealed an HR of 1.50 (95% CI 1.32–1.70; p < 0.001), suggesting that patients with PD-L1 overexpression experience inferior OS. Subgroup analysis revealed that elevated PD-L1 remained a significant prognostic indicator for worse OS, irrespective of sample size, cut-off value, ethnicity, and Newcastle-Ottawa Scale score. Moreover, PD-L1 overexpression was associated with non-epithelioid histology (odds ratio 4.30 [95% CI 1.89–9.74]; p < 0.001).ConclusionsResults of this meta-analysis show that elevated expression of PD-L1 could be a factor predicting poorer survival in patients with MPM.  相似文献   
74.
75.
Abstract

The autoimmune condition Hashimoto’s thyroiditis (HT) is a disease wherein lymphocytes mediate the autoimmune damage and destruction of the thyroid gland. There are currently no effective means of treating HT, with the primary strategies of thyroid hormone therapy, surgery, or immunomodulatory therapy being associated with serious risks and side effects. There is thus a clear and urgent need to identify novel treatments for HT. In this study, we utilize female SD rats induced HT to evaluated the ability of transplanted MSCs to regulate Th17/Treg interactions in a rat Hashimoto’s thyroiditis (HT) model system. The results showed that Rats in the HT model group exhibited increased thyroid autoantibody levels consistent with successful model development, whereas these levels were lower in rats treated with MSCs. There were also fewer thyroid lesions and less lymphoid infiltration of the thyroid in MSC-treated rats relative to HT model rats, as well as fewer Th17 cells and more Treg cells – an observation consistent with the cytokine analyses. All of these showed that MSCs can regulate Th17/Treg interactions in a rat Hashimoto’s thyroiditis (HT) model system. It suggested that transplanted MSCs could be a potential immunotherapy strategy for the treatment of Hashimoto’s thyroiditis.  相似文献   
76.
目的:探讨醛-酮还原酶家族7成员A3(AKR7A3)在肺腺癌中的异常表达及与临床病理特征的关系,并探究其临床意义。方法:采用生物信息学数据库分析、免疫组化、Western Blot、Real-time PCR等方法对肺腺癌组织及不同细胞中AKR7A3的表达进行检测与分析。结果:Oncomine数据库分析结果显示,在肺腺癌中,AKR7A3的表达普遍高于正常肺组织,分别为正常肺组织的1.811倍(P=0.022)、1.356倍(P<0.01)、1.413倍(P=0.002)。Kaplan-Meier Plotter数据库分析结果显示,AKR7A3高表达的患者较低表达的患者生存时间缩短,差异具有统计学意义(P=0.003 7)。免疫组化染色显示肺腺癌组织中AKR7A3的表达较癌旁增高,在与临床病理特征的相关性分析中,发现其与肿瘤分化程度(P<0.01)、淋巴结转移情况(P=0.029)以及TNM分期(P<0.01)相关,且会造成患者生存时间缩短(P=0.031)。Cox多因素分析表明AKR7A3可能是影响肺腺癌患者预后的独立危险因素(P=0.012)。Western Blot及Real-time PCR实验提示不同肺腺癌细胞中AKR7A3蛋白及mRNA表达普遍增高。结论:AKR7A3在肺腺癌中表达增高,对预后有不良影响,有促进肿瘤发生发展的作用。  相似文献   
77.
Immune dysregulation is a cardinal feature of autoimmune diseases and chronic microbial infections. In particular, regulatory T cells are downregulated in autoimmune diseases while upregulated in chronic microbial infections. FOXP3 is the master regulator of Treg development. Treg-specific demethylated region (TSDR) is a highly conserved locus on the FOXP3 gene that is fully demethylated in natural Tregs but methylated in effector T cells. In our study, we used high resolution melt-polymerase chain reaction (HRM-PCR) to determine the FOXP3 TSDR methylation status in autoimmune diseases and chronic microbial infections. We found that FOXP3 TSDR to have the highest mean melting temperature (highly methylated) in active SLE patients compared to all the other groups (p?<?0.001). The psoriasis group also had a significantly high mean melting temperature (78.62?±?0.20) when compared with the inactive SLE group (78.49?±?0.29, p?<?0.05) and control group (78.44?±?0.25, p?<?0.01). There was no significant difference in melting temperature between inactive SLE and healthy controls. Disease activity in SLE was directly associated with methylation of the FOXP3 TSDR. On the other hand, patients with chronic microbial infections had significantly lower FOXP3 TSDR mean melting temperature (demethylated) when compared with healthy controls (78.28?±?0.21 vs 78.44?±?0.25, p?<?0.05). Our results suggest that the use of HRM-PCR to detect FOXP3 TSDR methylation status is a reliable and easy method to predict natural regulatory T cell levels in peripheral blood in different disease conditions. Determining FOXP3 TSDR methylation status can be a useful tool in diagnosis, and monitoring the severity of autoimmune diseases and chronic microbial infections.  相似文献   
78.
Sirt5 is known to functionally regulate mitochondrial proteins by altering posttranslational modifications, including lysine desuccinylation. While roles for Sirt5 as either a tumor promoter or suppressor, or in chemoresistance, have been implicated in other cancers, the function of Sirt5 in cutaneous melanoma has not been well examined. Therefore, to determine whether Sirt5 is necessary for BrafV600E‐mediated melanoma formation and/or disease progression, we crossed a genetically engineered murine melanoma model (TyrCreERT2/+; BrafLSLV600E/+; Ptenflox/flox) to Sirt5?/? knockout animals. In addition, we tested for synergism with a selective BRAF (V600E) inhibitor in Sirt5?/? mouse melanoma cells. Taken together, this report demonstrates that, in these models, Sirt5 is dispensable for BrafV600E‐mediated cutaneous melanoma formation and growth in vivo, and does not improve sensitivity to a selective BRAF inhibitor.  相似文献   
79.
内镜治疗技术的发展进一步推动了早期胃癌的微创治疗。然而,随之而来的问题是,部分接受内镜治疗的病人会出现非治愈性切除。早期胃癌内镜治疗后非治愈性病人的后续处理原则值得进一步关注。结合欧洲肿瘤内科学会(ESMO)、美国国家综合癌症网络(NCCN)及日本胃癌学会等国际指南及相关临床研究并回顾分析单中心数据后可得出结论,eCura-C的病人具有相对较高的癌残留风险,在与病人充分沟通后可考虑追加手术,但仍有较高的术后病理学无癌残留的风险。术式选择和切除范围可参考早期胃癌相关规定。如何准确预测非治愈性病人的淋巴结转移仍是未来的重点。前哨淋巴结活检及腹腔镜内镜联合手术是未来的发展方向。  相似文献   
80.
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