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   194976篇
  免费   15096篇
  国内免费   4745篇
耳鼻咽喉   1483篇
儿科学   2906篇
妇产科学   3234篇
基础医学   25472篇
口腔科学   3689篇
临床医学   14236篇
内科学   24884篇
皮肤病学   2431篇
神经病学   12961篇
特种医学   7602篇
外国民族医学   3篇
外科学   16074篇
综合类   26181篇
现状与发展   27篇
一般理论   8篇
预防医学   15727篇
眼科学   2494篇
药学   28400篇
  58篇
中国医学   13401篇
肿瘤学   13546篇
  2024年   157篇
  2023年   2399篇
  2022年   3399篇
  2021年   7517篇
  2020年   6582篇
  2019年   6564篇
  2018年   6686篇
  2017年   7271篇
  2016年   7393篇
  2015年   7030篇
  2014年   8356篇
  2013年   12457篇
  2012年   10032篇
  2011年   12119篇
  2010年   7744篇
  2009年   7839篇
  2008年   9454篇
  2007年   10269篇
  2006年   9684篇
  2005年   8984篇
  2004年   7626篇
  2003年   6876篇
  2002年   5415篇
  2001年   4813篇
  2000年   4080篇
  1999年   3421篇
  1998年   2579篇
  1997年   2647篇
  1996年   2463篇
  1995年   2336篇
  1994年   2232篇
  1993年   1875篇
  1992年   1714篇
  1991年   1633篇
  1990年   1363篇
  1989年   1137篇
  1988年   1098篇
  1987年   977篇
  1986年   915篇
  1985年   1299篇
  1984年   1050篇
  1983年   793篇
  1982年   825篇
  1981年   677篇
  1980年   653篇
  1979年   516篇
  1978年   341篇
  1977年   288篇
  1976年   262篇
  1975年   198篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
61.
《Saudi Pharmaceutical Journal》2022,30(11):1665-1671
5-fluorouracil (5FU) is widely used to treat colorectal cancer (CC) and its main mechanisms of anticancer action are through generation of ROS which often result in inflammation. Here, we test the effect of Lycopene against 5FU in Caco2 cell line. Caco2 cells were exposed to 3 µg/ml of 5FU alone or with 60, 90, 120 µg/ml of lycopene. This was followed by assessment of cytotoxicity, oxidative stress, and gene expression of inflammatory genes. Our findings showed that Lycopene and 5FU co-exposure induced dose-dependent cytotoxic effect without compromising the membrane integrity based on the LDH assay. Lycopene also significantly enhanced 5FU-induced SOD activity and GSH level compared to control for all mixture concentrations (p < 0.01). Lycopene alone and combination with 5FU-induced expression of IL-1β, TNF-α, and IL-6. Furthermore, IFN-γ expression was significantly enhanced by only mixture of lycopene (90 µg/ml) and 5FU (p < 0.05). In conclusion, Lycopene supplementation with 5FU therapy resulted in improvement in antioxidant parameters such as catalase and GSH levels giving the cell capacity to cope with 5FU-mediated oxidative stress. Lycopene also enhanced IFN-γ expression in the presence of 5FU, which may activate antitumor effects further enhancing the cancer killing effect of 5FU.  相似文献   
62.

目的:探讨血清尿酸(SUA)、胱抑素C(CysC)水平与糖尿病视网膜病变(DR)的关系。

方法:前瞻性研究。选取2019-05/2021-05本院收治无DR的2型糖尿病(T2DM)患者53例和DR患者83例,DR患者中包括非增殖型糖尿病视网膜病变(NPDR)47例、增殖型糖尿病视网膜病变(PDR)36例。另选取同期体检中心体检健康者48人作为对照组。比较受试者血清学指标,尿酸氧化酶法检测SUA水平,免疫比浊法检测血清CysC含量,Spearman相关性分析血清SUA、CysC与其他血清学指标的相关性,多因素线性逐步回归法分析血清SUA、CysC的影响因素,使用受试者工作特征曲线(ROC)分析血清SUA、CysC对DR预测效能。

结果:T2DM组、NPDR组和PDR组的体质量指数(BMI)、收缩压(SBP)均明显高于对照组(均P<0.05),PDR组的SBP均明显高于T2DM组和NPDR组(均P<0.05),NPDR组和PDR组糖尿病病程均明显高于T2DM组(均P<0.05),PDR组糖尿病病程明显高于NPDR组(P<0.05)。对照组、T2DM组、NPDR组、PDR组纳入对象中空腹血糖(FPG)、糖化血红蛋白(HbA1c)、SUA、CysC水平呈逐渐明显升高趋势(均P<0.001),PDR组的低密度脂蛋白胆固醇(LDL-C)、甘油三酯(TG)水平明显高于对照组(均P<0.05),而高密度脂蛋白胆固醇(HDL-C)水平明显低于对照组(P<0.05)。血清SUA水平与FPG、HbA1c、TC、TG水平呈正相关(rs=0.564、0.631、0.513、0.408,P<0.001),与HDL-C、LDL-C无相关性(rs=-0.061、0.035,P>0.05); 血清 CysC水平与FPG、HbA1c、TC、TG水平呈正相关(rs=0.524、0.692、0.395、0.435,P<0.001),与HDL-C、LDL-C无相关性(rs=-0.012、0.049,P>0.05),FPG、HbA1c、TC、TG是血清SUA、CysC水平影响因素(P<0.001)。SUA、CysC联合检测时曲线下面积(AUC)(0.892,95%CI:0.840~0.944,敏感性71.1%,特异性94.3%)显著高于其单独检测AUC\〖SUA(0.807,95%CI:0.735~0.879,敏感性69.9%,特异性75.5%)、CysC(0.763,95%CI:0.684~0.841,敏感性69.9%,特异性75.5%)\〗(均P<0.05)。

结论:随着DR病情严重程度加重而血清SUA、CysC水平逐渐升高。血清SUA、CysC联合检测可提高DR诊断预测效能。  相似文献   

63.
Cyanidin-3-glucoside (C3G) is a well-known natural anthocyanin with antioxidant and anti-inflammatory properties. In this study, we explored the role and action mechanism of C3G in high glucose (HG)-induced damage of human nucleus pulposus cells (HNPCs). Cell viability was assessed by CCK-8 assay. TUNEL assay was performed for detecting apoptotic rate. Western blot was performed to determine the expression levels of cl-caspase-3, caspase-3, Bax, Bim, collagen II, aggrecan, MMP-3, MMP-13, and ADAMTS5. Reactive oxygen species (ROS) generation was analyzed using DCFH-DA staining. The Nrf2 was knocked down or overexpressed in HNPCs through transfection with si-Nrf2 or pcDNA3.0-Nrf2. C3G treatment (12.5, 25, and 50 μM) improved cell viability of HNPCs under HG condition. HG-induced cell apoptosis of HNPCs was attenuated by C3G with decreased apoptotic rate and relative levels of cl-caspase-3/caspase-3, Bax, and Bim. C3G treatment caused significant increase in expression levels of collagen II and aggrecan and decrease in the relative levels of MMP-3, MMP-13, and ADAMTS5. After treatment with C3G, ROS generation in HNPCs was markedly reduced. Treatment with N-acetylcysteine (NAC) reversed HG-induced cell apoptosis and extracellular matrix (ECM) degradation. C3G treatment induced the expression of Nrf2 and HO-1 in HG-induced HNPCs. Moreover, knockdown of Nrf2 reversed the inhibitory effect of C3G on ROS production. Summarily, C3G exerted a protective effect on ROS-mediated cellular damage in HNPCs under HG condition, which was attributed to the induction of the Nrf2/HO-1 signaling pathway.  相似文献   
64.
目的:通过检索《针灸大成》中与气海穴治疗作用相关的文献条文,总结气海穴在治疗各系统疾病中运用频次较高的疾病及其配穴规律,为临床针灸对气海穴的使用提供理论支持。方法:以《中华医典》(第五版)中《针灸大成》作为文献检索来源,将气海穴及气海穴的别称“脖胦”“下肓”“丹田”“肓之原”“肓原”“下言”和“气泽”为检索词,用计算机检索工具及人工检索相结合的方法检索符合要求的文献条文,通过建立本研究的数据库,频次分析、条形统计图比较分析等方法,总结出气海穴在治疗各系统疾病中的运用频次及其配穴规律。结果:在《针灸大成》所涉及的条文中,气海穴尤善治疗内科疾病,在治疗内科疾病中排名前3位的是脾胃系病症、气血津液疾病、肾系病症和妇科疾病,气海穴配穴习惯为上下配穴法,同名经配穴法,以及前后配穴法,其中主要为前后配穴法和同名经配穴法。结论:气海穴《针灸大成》中单穴应用占比最高,而在气海穴众多配穴中,运用了本经配穴法、上下配穴法、前后配穴法,配穴归经主要来自任脉和足太阳膀胱经。同名经配穴法,同气相求,可增加疗效;与气海穴配伍较多的足太阳膀胱经以背腧穴为主,此为前后配穴法,亦称腹背阴阳配穴法,腹部为阴,腰背为阳,前后配穴法可起到“从阳引阴”亦可“从阴引阳”的作用,以达到调节阴阳,调和脏法,调畅经络的目的。  相似文献   
65.
Myelofibrosis is a heterogeneous myeloproliferative neoplasm characterized by chronic inflammation, progressive bone marrow failure, and hepatosplenic extramedullary hematopoiesis. Treatments like Janus kinase inhibitor monotherapy (e.g., ruxolitinib) provide significant spleen and symptom relief but demonstrate limited ability to lead to a durable disease modification. There is an urgent unmet medical need for treatments with a novel mechanism of action that can modify the underlying pathophysiology and affect the disease course of myelofibrosis. This review highlights the role of B-cell lymphoma (BCL) protein BCL-extra large (BCL-XL) in disease pathogenesis and the potential role that navitoclax, a BCL-extra large/BCL-2 inhibitor, may have in myelofibrosis treatment.  相似文献   
66.
67.
ObjectiveWith this case report, we would like to highlight the importance of a multidisciplinary approach and atypical findings of congenital high airway obstruction sequence (CHAOS), anhydramnios, and renal dysgenesis in the prenatal diagnosis of Fraser syndrome (FS).Case reportA 25-year-old primigravida at 19 weeks of routine anomaly scan revealed abnormal sonographic findings such as fetal bilateral dysplastic small kidneys and gross oligohydramnios. The further detailed evaluation revealed that both fetal lungs were hyperechogenic with prominent (dilated) trachea and bronchi suggestive of CHAOS. Based on these findings, a diagnosis of FS was suspected. The couple was counseled and the pregnancy was terminated. The postmortem evaluation and novel homozygous variant in the FRAS1 gene confirmed the diagnosis of FS.ConclusionThe diagnosis and counseling of the patient were supported by a well-coordinated, multidisciplinary approach involving an obstetrician, a fetal medicine specialist, a medical geneticist, and a fetal pathologist.  相似文献   
68.
69.
70.
International recommendations encourage liberal administration of oxygen to patients having surgery under general anaesthesia, ostensibly to reduce surgical site infection. However, the optimal oxygen regimen to minimise postoperative complications and enhance recovery from surgery remains uncertain. The hospital operating theatre randomised oxygen (HOT-ROX) trial is a multicentre, patient- and assessor-blinded, parallel-group, randomised clinical trial designed to assess the effect of a restricted, standard care, or liberal peri-operative oxygen therapy regimen on days alive and at home after surgery in adults undergoing prolonged non-cardiac surgery under general anaesthesia. Here, we report the findings of the internal vanguard feasibility phase of the trial undertaken in four large metropolitan hospitals in Australia and New Zealand that included the first 210 patients of a planned overall 2640 trial sample, with eight pre-specified endpoints evaluating protocol implementation and safety. We screened a total of 956 participants between 1 September 2019 and 26 January 2021, with data from 210 participants included in the analysis. Median (IQR [range]) time-weighted average intra-operative FiO2 was 0.30 (0.26–0.35 [0.20–0.59]) and 0.47 (0.44–0.51 [0.37–0.68]) for restricted and standard care, respectively (mean difference (95%CI) 0.17 (0.14–0.20), p < 0.001). Median time-weighted average intra-operative FiO2 was 0.83 (0.80–0.85 [0.70–0.91]) for liberal oxygen therapy (mean difference (95%CI) compared with standard care 0.36 (0.33–0.39), p < 0.001). All feasibility endpoints were met. There were no significant patient adverse events. These data support the feasibility of proceeding with the HOT-ROX trial without major protocol modifications.  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