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   14854篇
  免费   1854篇
  国内免费   1030篇
耳鼻咽喉   122篇
儿科学   237篇
妇产科学   93篇
基础医学   1289篇
口腔科学   334篇
临床医学   1781篇
内科学   1689篇
皮肤病学   131篇
神经病学   523篇
特种医学   546篇
外国民族医学   1篇
外科学   1405篇
综合类   3429篇
现状与发展   3篇
预防医学   1382篇
眼科学   353篇
药学   2004篇
  28篇
中国医学   1586篇
肿瘤学   802篇
  2024年   127篇
  2023年   317篇
  2022年   765篇
  2021年   902篇
  2020年   768篇
  2019年   542篇
  2018年   560篇
  2017年   549篇
  2016年   474篇
  2015年   748篇
  2014年   875篇
  2013年   984篇
  2012年   1306篇
  2011年   1331篇
  2010年   1099篇
  2009年   978篇
  2008年   985篇
  2007年   892篇
  2006年   719篇
  2005年   637篇
  2004年   433篇
  2003年   397篇
  2002年   325篇
  2001年   244篇
  2000年   221篇
  1999年   134篇
  1998年   72篇
  1997年   78篇
  1996年   49篇
  1995年   33篇
  1994年   35篇
  1993年   26篇
  1992年   21篇
  1991年   17篇
  1990年   27篇
  1989年   15篇
  1988年   17篇
  1987年   7篇
  1986年   3篇
  1985年   3篇
  1983年   3篇
  1982年   5篇
  1980年   1篇
  1972年   1篇
  1965年   3篇
  1964年   1篇
  1962年   1篇
  1959年   1篇
  1957年   2篇
  1956年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
目的:探讨L型氨基酸转运蛋白1(L-type amino acid transporter 1,LAT)表达水平与非肌层浸润性膀胱癌患者术后复发风险的相关性。方法:选取2021年2月至2022年2月于重庆医科大学附属永川医院接受手术治疗的非肌层浸润性膀胱癌患者108例作为研究对象,采用反转录酶聚合酶链反应测定膀胱癌组织(取自肿瘤所在部位区域)和癌旁组织(取自邻近正常区域组织)LAT1表达含量,对比膀胱癌组织和癌旁组织LAT1表达水平。同时根据膀胱癌组织LAT1表达含量的二分位数将所有患者分为高表达组和低表达组,对比2组临床病理参数。随访观察12个月观察2组术后复发情况,采用Kaplan-Meier曲线分析对比2组术后复发风险,使用多变量Cox比例风险回归模型确定术后复发的影响因素。结果:膀胱癌组织LAT1表达水平(1.80±0.35)较配对的癌旁组织LAT1表达水平(1.05±0.17)高(P<0.05);LAT1高表达组吸烟史、临床分期T1占比较LAT1低表达组高(P<0.05);108例膀胱肿瘤患者术后的平均随访时间为(10.84±1.94)个月,...  相似文献   
32.
随着剖宫产率的逐年上升,剖宫产术后再次妊娠率也随之增加.术后再次妊娠能否经阴道分娩已成为产科医生重视的问题.近年越来越多的研究从剖官产术后阴道分娩的适应证、禁忌证、高危因素、注意事项、缩宫素的应用、影响因素、优越性及危险性等方面探讨阴道试产的可行性.研究证实,剖宫产史并非再次妊娠剖宫产的绝对指征,剖宫产术后阴道分娩与再次剖宫产相比利多弊少,选择合适的病例进行阴道试产是安全可行的.  相似文献   
33.
ObjectiveTo investigate the effects of hand–foot syndrome (HFS) and fatigue on disease progression and survival in patients treated with sorafenib followed by regorafenib for advanced hepatocellular carcinoma.MethodsA retrospective analysis of patients with advanced hepatocellular carcinoma treated with sorafenib in our hospital from 1 October 2018 to 31 October 2021 was performed, and clinical and pathological data and follow-up results were obtained. Patients were divided into groups according to the severity of HFS and fatigue. Survival analysis among the groups was performed using the Kaplan–Meier method, continuous variables were analyzed using the t-test, and factors associated with survival were evaluated using multivariate Cox regression analysis.ResultsThe study included 150 men and 23 women with a mean age of 60.77 years (range: 40–85 years). The median overall survival (OS), progression-free survival (PFS), and time to tumor progression (TTP) increased with increasing severity of HFS. Conversely, the median OS, PFS, and TTP decreased with increasing severity of fatigueConclusionHFS and fatigue were independent risk factors affecting TTP, PFS, and OS among patients treated with sorafenib followed by regorafenib for advanced hepatocellular carcinoma.  相似文献   
34.
目的观察动物口服六味银杏胶囊的急性毒性和长期毒性反应。方法采用最大给药量法测定小鼠口服六味银杏胶囊的急性毒性;以20.0,10.0,5.0 g生药.kg-1.d-13个剂量的六味银杏胶囊(相当于临床用量68、34、17倍)灌胃SD大鼠,连续24周,观察服药24周及停药4周后,大鼠的生长发育、血液学、血液生化学、组织病理指标的变化。结果小鼠1天内口服六味银杏胶囊最大给药量为190.0 g生药/kg,相当于临床用量的700倍。长期毒性实验中,各剂量组与空白对照组比较,大鼠一般状况,体重增长,血液学、血液生化指标,主要脏器系数,肉眼观察及镜下组织形态学观察均无明显差异或异常。结论六味银杏胶囊临床用药范围内应用是比较安全的。  相似文献   
35.
中西医结合治疗系统性红斑狼疮现状及评析   总被引:4,自引:1,他引:4  
系统性红斑狼疮(SLE)是一种以多脏器、多系统损害为主的自身免疫性疾病,多见于青壮年女性,可急性或慢性隐匿性发作,反复恶化与自行缓解常交替进行,病情日趋恶化,晚期常因全身多脏器衰竭、心肾损害而预后不良。我国初步调查SLE患者发病率为20~70/10万人,属高发地区。且近年统计资料显示其年发病率有逐渐上升的趋势,患者亦日趋年轻化。本病目前尚无根治的方法。随着激素类药物及免疫抑制剂的应用,SLE的病死率有下降趋势,在90年代5年、10年、20年生存率已分别达97%、90%和80%。但是由于本病长期反复发作,西医治疗药物许多都有很强的毒副作用,严重影响着病人的生存质量。  相似文献   
36.
获取高分辨率和高反差的生物样品电镜图象受许多因素的影响,它包括切片厚度的选择,电镜的校直合轴、加速电压的选择、以及聚焦方法和曝光时间等。除生物样品制备技术这一重要因素外,必须考虑到上述各因素间的相互关系及其综合选择、然后才有可能获得高质量的生物样品的超微结构图象。  相似文献   
37.
目的 分析深圳市恶性肿瘤死亡特征和分布情况,为政府制定恶性肿瘤的防控策略提供参考依据.方法 采用国际疾病分类标准(ICD-10)进行编码分类,运用描述流行病学研究,对2017年1月1日-2019年12月31日深圳市常住居民恶性肿瘤10 612例死亡病例进行分析,分别计算死亡率、死因顺位等.结果 2017年-2019年间...  相似文献   
38.
BackgroundThe prevalence of sleep‐disordered breathing (SDB) is closely related to the severity of heart failure (HF), and the severity of HF is different in patients with HF of different etiologies. Hypothesis: This study aimed to explore the prevalence of SDB in patients with HFof different etiologies.MethodsHospitalized HF patients were consecutively enrolled. All patients underwent portable overnight cardiorespiratory polygraphy. Patients were divided into five groups according to the etiology of HF: ischemic, hypertensive, myocardial, valvular, and arrhythmic. The prevalence of SDB and clinical data was compared among the five groups.ResultsIn total, 248 patients were enrolled in this study. The prevalence of SDB in HF was 70.6%, with the prevalence of obstructive sleep apnea (OSA) at 47.6% and central sleep apnea (CSA) at 23.0%. Patients were divided into five groups: ischemic, hypertensive, myocardial, valvular, and arrhythmic. The prevalence of SDB among the five groups was 75.3%, 81.4%, 77.8%, 51.9%, and 58.5% (p = .014), respectively. The prevalence of OSA among the five groups was 42.7%, 72.1%, 36.1%, 37.0%, and 49.1% (p = .009), whereas the CSA was 32.6%, 9.3%, 41.7%, 14.8%, and 9.4% (p < .001), respectively.ConclusionsSDB is common in HF patients. The prevalence and types of SDB varied in HF with different etiologies, which may be related to the different severities of HF. SDB was highly prevalent in patients with ischemic, hypertensive, and myocardial HF. Hypertensive HF patients were mainly complicated with OSA, while myocardial HF patients were mainly complicated with CSA. Both conditions were highly prevalent in ischemic HF patients. The prevalence of SDB was relatively low in valvular and arrhythmic HF patients, and OSA was the main type.  相似文献   
39.
This study built theoretical and practical models to evaluate the corrosion resistance of concrete for coastal offshore structures in Vietnam. A mathematical model was developed in the form of a system of nonlinear partial differential equations characterizing the diffusion “free calcium hydroxide” in a solid of a concrete structure. The model describes the process of non-stationary mass conductivity observed in the “concrete structure—marine environment” system under non-uniform arbitrary initial conditions, as well as combined boundary conditions of the second and third kind, taking into account the nonlinear nature of the coefficients of mass conductivity k and mass transfer β. It was shown that the solution of the boundary value problem of non-stationary mass conductivity allows us to conclude about the duration of the service life of a concrete structure, which will be determined by the processes occurring at the interface: in concrete—mass conductivity, depending on the structural and mechanical characteristics of hydraulic structures, and in the liquid phase—mass transfer, determined by the conditions of interaction at the interface of the indicated phases.  相似文献   
40.
Background:The 2020 European Society of Cardiology guidelines do not recommend pretreatment for nonST-segment elevation myocardial infarction (NSTEMI) patients with unclear coronary anatomy, which is inconsistent with our routine preoperative approach to loading P2Y12 receptor inhibitors (e.g., preoperative loading of 300 mg of clopidogrel).Objectives:The purpose of our study was to compare the safety and effectiveness of P2Y12 inhibitors administered before coronary angiography or at least before percutaneous coronary intervention (PCI) with during or after PCI.Methods:Cochrane, PubMed, and Embase databases were searched. The primary effect endpoint and safety endpoint were any-cause death and major bleeding, respectively. Major adverse cardiovascular events, myocardial infarction and revascularization were also analyzed.Results:Our search identified 9 trials. P2Y12 inhibitor pretreatment was associated with lower death from any cause (OR 0.62, 95% CI 0.53–0.72, P < 0.00001) without increasing the risk of bleeding (OR 1.02, 95% CI 0.80–1.30, P = 0.89). However, prasugrel or ticagrelor pretreatment was not associated with a lower risk of mortality (OR 0.70, 95% CI 0.31–1.59, P = 0.40) and increased the risk of bleeding (OR 1.67, 95% CI 1.10–2.54, P = 0.02).Conclusions:In summary, clopidogrel pretreatment was associated with significantly lower mortality, major adverse cardiovascular events, myocardial infarction and revascularization with no increase in major bleeding. However, these advantages were not observed with prasugrel or ticagrelor pretreatment.  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