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   50185篇
  免费   3430篇
  国内免费   1901篇
耳鼻咽喉   179篇
儿科学   1034篇
妇产科学   525篇
基础医学   4434篇
口腔科学   444篇
临床医学   5135篇
内科学   10540篇
皮肤病学   293篇
神经病学   3415篇
特种医学   1877篇
外国民族医学   1篇
外科学   4744篇
综合类   8722篇
预防医学   2862篇
眼科学   729篇
药学   6936篇
  22篇
中国医学   2579篇
肿瘤学   1045篇
  2023年   585篇
  2022年   870篇
  2021年   1541篇
  2020年   1443篇
  2019年   1198篇
  2018年   1227篇
  2017年   1406篇
  2016年   1550篇
  2015年   1600篇
  2014年   3165篇
  2013年   3466篇
  2012年   3225篇
  2011年   3528篇
  2010年   2923篇
  2009年   2820篇
  2008年   2977篇
  2007年   2692篇
  2006年   2356篇
  2005年   2161篇
  2004年   1772篇
  2003年   1616篇
  2002年   1348篇
  2001年   1162篇
  2000年   969篇
  1999年   738篇
  1998年   598篇
  1997年   573篇
  1996年   529篇
  1995年   569篇
  1994年   470篇
  1993年   419篇
  1992年   314篇
  1991年   349篇
  1990年   270篇
  1989年   232篇
  1988年   257篇
  1987年   201篇
  1986年   209篇
  1985年   280篇
  1984年   252篇
  1983年   163篇
  1982年   212篇
  1981年   185篇
  1980年   196篇
  1979年   146篇
  1978年   132篇
  1977年   108篇
  1976年   96篇
  1975年   70篇
  1973年   75篇
排序方式: 共有10000条查询结果,搜索用时 15 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.
目的考察半夏泻心汤联合甘精胰岛素注射液对脾弱胃强型2型糖尿病患者血糖及免疫指标的影响。方法选取2019年1月~2020年12月于天津市河西区康复医院诊治的脾弱胃强型2型糖尿病患者120例,随机分为对照组和观察组,每组60例,对照组仅给予甘精胰岛素注射液,观察组给予半夏泻心汤联合甘精胰岛素注射液。比较两组治疗后1个月和3个月患者临床治疗有效率,治疗前、治疗后1个月和3个月糖化血红蛋白(glycosylated hemoglobin,HbA1c)和空腹血糖(fasting plasma glucose,FPG)及免疫细胞CD3+、CD4+、CD8+和CD4+/CD8+水平。结果相比于对照组,观察组治疗后1个月和3个月临床治疗有效率显著提高(P<0.05);两组治疗前血糖和免疫相关指标相比,差异无统计学意义(P>0.05),治疗后1个月和3个月,两组患者HbA1c、FPG和CD8+相比于治疗前均显著降低,而CD3+、CD4+和CD4+/CD8+显著升高(P<0.05);治疗后3个月,两组患者HbA1c、FPG和CD8+相比于治疗后1个月均显著降低,而CD3+、CD4+和CD4+/CD8+显著升高(P<0.05);观察组治疗后1个月和3个月HbA1c、FPG和CD8+相比于对照组均显著降低,而CD3+、CD4+和CD4+/CD8+显著升高(P<0.05)。结论半夏泻心汤联合甘精胰岛素注射液治疗脾弱胃强型2型糖尿病患者的临床效果较好,能够有效降低患者血糖水平,改善机体免疫水平。  相似文献   
3.
目的 考察注射用丹参多酚酸(SAFI)对脑缺血大鼠急性期用药的可行性,明确大鼠脑缺血再灌注后脑血流的变化及其与远期运动功能恢复之间的相关性。方法 将Wistar大鼠随机分为假手术组、模型组及SAFI (21 mg·kg-1)组。SAFI组根据不同给药时机又分为3个亚组,分别是再灌后立即给药组(SAFI 0周)、再灌后1周给药组(SAFI 1周)、再灌后2周给药组(SAFI 2周),每组每天给药1次,连续ip 7 d,为保持一致性,其余时间均ip生理盐水,假手术组及模型组分别ip等量生理盐水。采用线栓法构建大鼠脑缺血再灌注模型,假手术组仅分离血管。通过观测大鼠一般状态、评估大鼠神经功能和脑梗死体积百分比考察SAFI急性期给药的药效作用;利用激光多普勒技术检测大鼠局部脑血流量(rCBF);通过转棒实验和步态实验分析大鼠的运动能力;通过Pearson相关性分析方法评估不同时间点的脑血流变化与远期运动功能恢复之间的相关性。结果 与模型组比较,SAFI 0周组大鼠的神经功能评分显著降低(P<0.01),脑梗死体积百分比显著降低(P<0.01),rCBF显著提升(P<0.05、0.01),死亡率明显下降;与模型组比较,SAFI 0周组大鼠在转棒仪上跌落潜伏期显著增加(P<0.05、0.01),SAFI 0周组大鼠在步态仪上运动速度显著增加(P<0.01),四肢的摆动时间、站立时间和步态周期显著下降(P<0.05、0.01),四肢(除左后肢外)的步幅显著增加(P<0.05、0.01)。与SAFI 1、2周组比较,SAFI 0周组脑梗死体积百分比显著降低(P<0.01),死亡率降低,rCBF显著升高(P<0.05、0.01),明显促进了神经行为学功能及运动功能的恢复。Pearson相关性分析结果表明脑缺血再灌注损伤后早期的脑血流恢复与远期运动功能呈线性相关。结论 SAFI在缺血急性期给药具有一定的可行性;脑缺血后梗死周边区域血流恢复对远期运动功能的恢复至关重要。  相似文献   
4.
BackgroundIschemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat.MethodsRat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed.ResultsPre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators.ConclusionOur result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction.  相似文献   
5.
6.
7.
AimThis review aims to summarize and discuss some of the most relevant clinical trials in epidemiology, diagnostics, and treatment of hypertension published in 2020 and 2021.Data synthesisThe trials included in this review are related to hypertension onset age and risk for future cardiovascular disease, reliability of different blood pressure monitoring methods, role of exercise-induced hypertension, treatment of hypertension in patients with SARS-CoV-2 infection, management of hypertension high-risk patient groups, e.g., in the elderly (≥80 years) and patients with atrial fibrillation, and the interplay between nutrition and hypertension, as well as recent insights into renal denervation for treatment of hypertension.ConclusionsHypertension onset age, nighttime blood pressure levels and a riser pattern are relevant for the prognosis of future cardiovascular diseases. The risk of coronary heart disease appears to increase linearly with increasing exercise systolic blood pressure. Renin-angiotensin system blockers are not associated with an increased risk for a severe course of COVID-19. In elderly patients, a risk-benefit assessment of intensified blood pressure control should be individually evaluated. A J-shaped association between cardiovascular disease and achieved blood pressure could also be demonstrated in patients with atrial fibrillation on anticoagulation. Salt restriction and lifestyle modification remain effective options in treating hypertensive patients at low cardiovascular risk. Sodium glucose co-transporter 2 inhibitors and Glucagon-like peptide-1 receptor agonists show BP-lowering effects. Renal denervation should be considered as an additional or alternative treatment option in selected patients with uncontrolled hypertension.  相似文献   
8.
9.
目的分析拔管后仍存在呼吸衰竭的患者序贯经鼻高流量湿化氧疗(HFNC)失败率及其危险因素。 方法回顾性分析2017年1月1日至2019年3月31日入住福建省立医院ICU气管插管拔管后行序贯HFNC的145例患者。根据HFNC成功与否将其分为HFNC成功组(113例)和HFNC失败组(32例)。比较两组患者的临床资料及实验室指标,并采用Logistic回归分析探究HFNC治疗失败的独立危险因素。 结果HFNC成功组和HFNC失败组患者插管原因(χ2 = 11.224,P = 0.024)、慢性心力衰竭(χ2 = 4.863,P = 0.027)、心脏瓣膜病(χ2 = 6.435,P = 0.011)、呼吸道病原学阳性(χ2 = 8.909,P = 0.003),拔管当天序贯器官衰竭估计评分(Z = 2.138,P = 0.032)、急性病生理学和长期健康评价Ⅱ评分(t = 2.307,P = 0.023),插管期间使用血管活性药物(χ2 = 4.153,P = 0.042)和雾化N-乙酰半胱氨酸(χ2 = 4.531,P = 0.033),拔管前2 d内中性粒细胞计数(t = 2.170,P = 0.032)、淋巴细胞总数<0.8 × 109/L(χ2 = 5.941,P = 0.024)、降钙素原(Z = 2.656,P = 0.008)比较,差异均有统计学意义。多因素Logistic回归分析结果显示,拔管前2 d内外周血淋巴细胞总数<0.8 × 109/L[比值比(OR)= 2.898,95%置信区间(CI)(1.059,7.935),P = 0.038]和呼吸道病原学阳性[OR = 4.617,95%CI(1.463,14.568),P = 0.009]为HFNC失败的独立危险因素。 结论拔管前2 d内外周血淋巴细胞计数<0.8 × 109/L和呼吸道病原体阳性为气管插管拔管后仍存在呼吸衰竭的患者序贯HFNC失败的独立危险因素。  相似文献   
10.
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