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   21297篇
  免费   1878篇
  国内免费   712篇
耳鼻咽喉   74篇
儿科学   337篇
妇产科学   69篇
基础医学   1011篇
口腔科学   50篇
临床医学   2389篇
内科学   8390篇
皮肤病学   30篇
神经病学   384篇
特种医学   1515篇
外国民族医学   6篇
外科学   4736篇
综合类   2858篇
预防医学   328篇
眼科学   76篇
药学   889篇
  19篇
中国医学   236篇
肿瘤学   490篇
  2024年   8篇
  2023年   534篇
  2022年   592篇
  2021年   1156篇
  2020年   1222篇
  2019年   1147篇
  2018年   1091篇
  2017年   806篇
  2016年   772篇
  2015年   868篇
  2014年   1622篇
  2013年   1561篇
  2012年   1041篇
  2011年   1240篇
  2010年   967篇
  2009年   1010篇
  2008年   939篇
  2007年   999篇
  2006年   846篇
  2005年   767篇
  2004年   623篇
  2003年   554篇
  2002年   551篇
  2001年   429篇
  2000年   293篇
  1999年   257篇
  1998年   261篇
  1997年   203篇
  1996年   191篇
  1995年   191篇
  1994年   160篇
  1993年   138篇
  1992年   106篇
  1991年   101篇
  1990年   80篇
  1989年   71篇
  1988年   61篇
  1987年   52篇
  1986年   61篇
  1985年   47篇
  1984年   52篇
  1983年   40篇
  1982年   39篇
  1981年   28篇
  1980年   27篇
  1979年   21篇
  1978年   15篇
  1977年   17篇
  1976年   12篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
1.
ObjectivesThe aim of this study was to test whether optical coherence tomographic (OCT) guidance would provide additional useful information beyond that obtained by angiography and lead to a shift in reperfusion strategy and improved clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) with early infarct artery patency.BackgroundAngiography is limited in assessing the underlying pathophysiological mechanisms of the culprit lesion.MethodsEROSION III (Optical Coherence Tomography–Guided Reperfusion in ST-Segment Elevation Myocardial Infarction With Early Infarct Artery Patency) is an open-label, prospective, multicenter, randomized, controlled study approved by the ethics committees of participating centers. Patients with STEMI who had angiographic diameter stenosis ≤ 70% and TIMI (Thrombolysis In Myocardial Infarction) flow grade 3 at presentation or after antegrade blood flow restoration were recruited and randomized to either OCT guidance or angiographic guidance. The primary efficacy endpoint was the rate of stent implantation.ResultsAmong 246 randomized patients, 226 (91.9%) constituted the per protocol set (112 with OCT guidance and 114 with angiographic guidance). The median diameter stenosis was 54.0% (IQR: 48.0%-61.0%) in the OCT guidance group and 53.5% (IQR: 43.8%-64.0%) in the angiographic guidance group (P = 0.57) before randomization. Stent implantation was performed in 49 of 112 patients (43.8%) in the OCT group and 67 of 114 patients (58.8%) in the angiographic group (P = 0.024), demonstrating a 15% reduction in stent implantation with OCT guidance. In patients treated with stent implantation, OCT guidance was associated with a favorable result with lower residual angiographic diameter stenosis (8.7% ± 3.7% vs 11.8% ± 4.6% in the angiographic guidance group; P < 0.001). Two patients (1 cardiac death, 1 stable angina) met the primary safety endpoint in the OCT guidance group, as did 3 patients (3 cardiac deaths) in the angiographic guidance group (1.8% vs 2.6%; P = 0.67). Reinfarction was not observed in either group. At 1 year, the rates of predefined cardiocerebrovascular events were comparable between the groups (11.6% after OCT guidance vs 9.6% after angiographic guidance; P = 0.66).ConclusionsIn patients with STEMI with early infarct artery patency, OCT guidance compared with angiographic guidance of reperfusion was associated with less stent implantation during primary percutaneous coronary intervention. These favorable results indicate the value of OCT imaging in optimizing the reperfusion strategy of patients with STEMI. (EROSION III: OCT- vs Angio-Based Reperfusion Strategy for STEMI; NCT03571269)  相似文献   
2.
主动脉瘤是一种多因素影响、具有潜在破裂风险的主动脉病理扩张性疾病。根据发病位置主动脉瘤可分为胸主动脉瘤和腹主动脉瘤。胸主动脉瘤的发生与年龄和性别相关性不大,而与遗传因素高度相关;腹主动脉瘤的发生与年龄、性别、动脉粥样硬化等相关,但与遗传关联性较弱。 主动脉瘤一般具有发病隐匿和破裂致死等特征,是严重威胁人类生命健康的慢性疾病,但其发病机制尚不完全清楚。主动脉瘤动物模型是研究人主动脉瘤的重要工具,对阐释主动脉瘤的病理生理学机制、研发和评价主动脉瘤的治疗药物都具有重要意义。当前关于腹主动脉瘤的动物模型有很多,也比较成熟,但是关于胸主动脉瘤的动物模型较少。实际上,多种方法诱导的腹主动脉瘤模型中,也会出现胸主动脉瘤,只不过发病率不同,胸主动脉瘤的发病率较低。本文将主动脉瘤动物模型归纳为非夹层主动脉瘤动物模型和夹层主动脉瘤动物模型,并简要综述这两类模型的构建方法及表型,为人类动脉瘤的防治研究提供参考。  相似文献   
3.
目的 探讨杂交手术在治疗累及弓部的Stanford B型主动脉夹层(TBAD)中的有效性和安全性。方法 前瞻性描述性研究。纳入2020年1月—2021年9月蚌埠医学院第一附属医院血管外科确诊为累及弓部的TBAD患者。其中男16例,女5例;年龄32~81(59.7±12.9)岁。患者均采用外科转流术和胸主动脉腔内修复术相结合设计的新的杂交手术治疗。观察指标:患者手术时间、术中出血量、术中转流血管通畅情况、有无Ⅰ型内漏、术后卧床时间、住院费用、术后住院时间、术后并发症以及死亡等指标。术后随访观察有无支架移位、再干预、支架内血栓形成、支架内再狭窄、移植物感染、各型内漏,转流血管通畅情况及真腔通畅情况。结果 患者手术均成功,术中均未出现Ⅰ型内漏。手术时间为(156.5±19.7)min,术中出血量为(70.2±25.6)mL,术后卧床时间为(4.3±1.7)d。11例患者使用人工血管行转流术,术后住院时间为(9.6±3.1)d,住院费用为(16.6±3.8)万元;另外10例使用自体大隐静脉,术后住院时间为(14.1±6.3)d,住院费用(剔除2例左颈总动脉植入支架病例)为(13.0±1.2)万元。21例患者术后仅1例出现腔隙性脑梗死,其余均未出现内脏缺血、下肢缺血、急性心功能不全、脑卒中、肺动脉栓塞、脑梗死、肺部感染和急性肾损伤等并发症,无死亡病例。21例患者术后随访时间为6~12(10.9±2.4)个月,所有患者支架无偏移,未发现内漏,支架段主动脉形态优良、真腔及血管旁路血流顺畅。患者均无再干预、支架内血栓形成、支架内再狭窄、移植物感染等情况发生。结论 在短中期的疗效观察中,杂交手术治疗累及弓部的TBAD安全、有效。  相似文献   
4.
ObjectiveTo evaluate the long-term incidence and outcome of aortic interventions for medically managed uncomplicated thoracic aortic dissections.MethodsBetween January 2012 and December 2018, 91 patients were discharged home with an uncomplicated, medically treated aortic dissection (involving the descending aorta with or without aortic arch involvement, no ascending involvement). After a median period of 4 (first quartile: 2, third quartile: 11) months, 30 patients (33%) required an aortic intervention. Patient characteristics, radiographic, treatment, and follow-up data were compared for patients with and without aortic interventions. A competing risk regression model was analyzed to identify independent predictors of aortic intervention and to predict the risk for intervention.ResultsPatients who underwent aortic interventions had significantly larger thoracic (P = .041) and abdominal (P = .015) aortic diameters, the dissection was significantly longer (P = .035), there were more communications between both lumina (P = .040), and the first communication was significantly closer to the left subclavian artery (P = .049). A descending thoracic aortic diameter exceeding 45 mm was predictive for an aortic intervention (P = .001; subdistribution hazard ratio: 3.51). The risk for aortic intervention was 27% ± 10% and 36% ± 11% after 1 and 3 years, respectively. Fourteen patients (47%) underwent thoracic endovascular aortic repair, 11 patients (37%) thoracic endovascular aortic repair and left carotid to subclavian bypass, 3 patients (10%) total arch replacement with the frozen elephant trunk technique, and 2 patients (7%) thoracoabdominal aortic replacement. We observed no in-hospital mortality.ConclusionsThe need for secondary aortic interventions in patients with initially medically managed, uncomplicated descending aortic dissections is substantial. The full spectrum of aortic treatment options (endovascular, hybrid, conventional open surgical) is required in these patients.  相似文献   
5.
6.
ObjectivesGuidelines suggest aortic valve replacement (AVR) for low-risk asymptomatic patients. Indications for transcatheter AVR now include low-risk patients, making it imperative to understand state-of-the-art surgical AVR (SAVR) in this population. Therefore, we compared SAVR outcomes in low-risk patients with those expected from Society of Thoracic Surgeons (STS) models and assessed their intermediate-term survival.MethodsFrom January 2005 to January 2017, 3493 isolated SAVRs were performed in 3474 patients with STS predicted risk of mortality <4%. Observed operative mortality and composite major morbidity or mortality were compared with STS-expected outcomes according to calendar year of surgery. Logistic regression analysis was used to identify risk factors for these outcomes. Patients were followed for time-related mortality.ResultsWith 15 observed operative deaths (0.43%) compared with 55 expected (1.6%), the observed:expected ratio was 0.27 for mortality (95% confidence interval [CI], 0.14-0.42), stroke 0.65 (95% CI, 0.41-0.89), and reoperation 0.50 (95% CI, 0.42-0.60). Major morbidity or mortality steadily declined, with probabilities of 8.6%, 6.7%, and 5.2% in 2006, 2011, and 2016, respectively, while STS-expected risk remained at approximately 12%. Mitral valve regurgitation, ventricular hypertrophy, pulmonary, renal, and hepatic failure, coronary artery disease, and earlier surgery date were residual risk factors. Survival was 98%, 91%, and 82% at 1, 5, and 9 years, respectively, superior to that predicted for the US age-race-sex–matched population.ConclusionsSTS risk models overestimate contemporary SAVR risk at a high-volume center, supporting efforts to create a more agile quality assessment program. SAVR in low-risk patients provides durable survival benefit, supporting early surgery and providing a benchmark for transcatheter AVR.  相似文献   
7.
AimsThis review aims to provide an update of available methods for imaging calcification activity and potential therapeutic options.Data SynthesisAortic valve calcification represents the most common heart valve condition requiring treatment among adults in Western societies. No medical therapies are proven to be effective in treating symptoms or reducing disease progression. Therefore, surgical or transcatheter aortic valve replacement remains the only available treatment option. Elevated circulating concentrations of lipoprotein(a) is strongly associated with degenerative aortic stenosis. This relationship was first observed in prospective observational studies, and the causal relationship was confirmed in genetic studies.ConclusionsNew therapeutic targets have been identified and new imaging techniques could be used to test the effectiveness of new agents and further clarify the pathophysiology of AVS. No therapy that specifically lowers Lp (a) levels has been approved for clinical use.  相似文献   
8.
目的探讨急性主动脉夹层患者首发症状与院前延迟的关系,为临床实施院前针对性健康教育提供参考。方法选取急性主动脉夹层患者488例,收集患者首发症状、一般资料、疾病相关因素、院前相关因素及院前时间,分析首发症状与院前延迟的关系。结果患者院前时间为135.5(48.3, 1 735.5) min,其中院前时间≤150 min 253例(51.8%),>150 min(即院前延迟)235例(48.2%);首发症状多为胸背痛[146例(29.9%)],其次为胸前痛124例(25.4%)、腹痛121例(24.8%)。Logistic回归分析发现自觉病情严重程度、胸背痛是院前延迟的保护因素(P<0.01),腹痛、四肢麻木/疼痛是急性主动脉夹层患者院前延迟的危险因素(P<0.05,P<0.01)。结论急性主动脉夹层患者常以胸背痛为首发症状,腹痛与四肢麻木/疼痛非典型症状是导致急性主动脉夹层患者出现院前延迟的主要因素。需对公众加强疾病相关知识的健康教育,早期采取正确的应对方式,积极就医,缩短院前时间。  相似文献   
9.
目的探讨基于微信平台的延续护理在颈动脉狭窄患者行颈动脉支架植入术后的应用效果。方法选择2019年1月—2020年12月于浙江省台州医院行颈动脉支架植入术的120例颈动脉狭窄患者为研究对象,根据随机数字表法将其分为干预组和对照组,各60例。对照组患者应用常规出院指导及随访护理,干预组在对照组的基础上实施基于微信平台的延续护理。采用简易生活质量量表(SF-36)、家庭亲密度与适应性量表中文版(FACESⅡ-CV)、自制治疗依从性调查问卷调查两组患者的生活质量、家庭功能、治疗依从性。结果干预后,干预组患者SF-36评分及FACESⅡ-CV评分、治疗依从性均高于对照组,差异均有统计学意义(P<0.05)。结论基于微信平台的延续护理可以有效提升行颈动脉支架植入术后颈动脉狭窄患者的生活质量、治疗依从性及家庭功能,值得临床应用。  相似文献   
10.
PurposeTo evaluate the feasibility and accuracy of a radiation-free implantation of a thoracic aortic stent graft employing fiberoptic and electromagnetic tracking in an anthropomorphic phantom.Materials and MethodsAn anthropomorphic phantom was manufactured based on computed tomography (CT) angiography data from a patient. An aortic stent graft application system was equipped with a fiber Bragg gratings and 3 electromagnetic sensors. The stent graft was navigated in the phantom by 3 interventionalists using the tracking data generated by both technologies. One implantation procedure was performed. The technical success of the procedure was evaluated using digital subtraction angiography and CT angiography (before and after the intervention). Tracking accuracy was determined at various anatomical landmarks based on separately acquired fluoroscopic images. The mean/maximum errors were measured for the stent graft application system and the tip/end of the stent graft.ResultsThe procedure resulted in technical success with a mean error below 3 mm for the entire application system and <2 mm for the position of the tip of the stent graft. Navigation/implantation and handling of the device were rated sufficiently accurate and on par with comparable, routinely used stent graft application systems.ConclusionsThe study demonstrates successful stent graft implantation during a thoracic endovascular aortic repair procedure employing advanced guidance techniques and avoiding fluoroscopic imaging. This is an essential step in facilitating the implantation of stent grafts and reducing the health risks associated with ionizing radiation during endovascular procedures.  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