全文获取类型
收费全文 | 14656篇 |
免费 | 920篇 |
国内免费 | 737篇 |
专业分类
耳鼻咽喉 | 136篇 |
儿科学 | 68篇 |
妇产科学 | 33篇 |
基础医学 | 1140篇 |
口腔科学 | 170篇 |
临床医学 | 2125篇 |
内科学 | 3773篇 |
皮肤病学 | 45篇 |
神经病学 | 1324篇 |
特种医学 | 968篇 |
外科学 | 1058篇 |
综合类 | 2779篇 |
现状与发展 | 1篇 |
预防医学 | 503篇 |
眼科学 | 48篇 |
药学 | 1346篇 |
5篇 | |
中国医学 | 723篇 |
肿瘤学 | 68篇 |
出版年
2024年 | 37篇 |
2023年 | 201篇 |
2022年 | 296篇 |
2021年 | 472篇 |
2020年 | 438篇 |
2019年 | 416篇 |
2018年 | 414篇 |
2017年 | 436篇 |
2016年 | 491篇 |
2015年 | 492篇 |
2014年 | 1068篇 |
2013年 | 1241篇 |
2012年 | 1045篇 |
2011年 | 1087篇 |
2010年 | 936篇 |
2009年 | 876篇 |
2008年 | 852篇 |
2007年 | 806篇 |
2006年 | 736篇 |
2005年 | 594篇 |
2004年 | 505篇 |
2003年 | 381篇 |
2002年 | 345篇 |
2001年 | 258篇 |
2000年 | 201篇 |
1999年 | 179篇 |
1998年 | 163篇 |
1997年 | 175篇 |
1996年 | 130篇 |
1995年 | 105篇 |
1994年 | 110篇 |
1993年 | 92篇 |
1992年 | 89篇 |
1991年 | 83篇 |
1990年 | 66篇 |
1989年 | 60篇 |
1988年 | 57篇 |
1987年 | 46篇 |
1986年 | 38篇 |
1985年 | 53篇 |
1984年 | 42篇 |
1983年 | 28篇 |
1982年 | 33篇 |
1981年 | 20篇 |
1980年 | 27篇 |
1979年 | 13篇 |
1978年 | 22篇 |
1977年 | 13篇 |
1976年 | 14篇 |
1972年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
目的 :观察 3 ,6 (二甲氨基 ) 二苯骈碘杂六环葡萄糖酸盐对AGEP引起的大鼠主动脉平滑肌细胞增殖及牛主动脉内皮细胞内皮素和一氧化氮改变的影响。方法 :采用牛血清白蛋白 (BSA)与不同浓度葡萄糖 (0 ,2 0 ,5 0 ,80mmol·L-1)体外孵育制备糖基化终产物 (AGEP) ,应用 [3 H] TdR掺入法和MTT比色法观察I-93对重度糖化的AGEP诱导的大鼠主动脉平滑肌细胞 (ASMC)增殖的影响 ;应用放射免疫技术及Greiss法观察I -93对AGEP引起的牛主动脉内皮细胞 (BAEC)释放内皮素 1(ET 1)和一氧化氮 (NO)的影响。结果 :I-93 10 -7~ 10 -5mol·L-1能明显抑制AGEP引起的ASMC增殖 ,其 [3 H] TdR掺入量和MTT比色法的最大抑制率分别为79 .4%和 44 .2 %。随AGEP糖浓度的增加 (2 0~ 80mmol·L-1) ,BAEC培养液中ET 1含量亦逐渐上升 [(4 93± 63 )~ (779± 10 5 )ng·L-1] ,I -93 10 -7~ 10 -5mol·L-1能明显抑制重度糖化的AGEP促进ET 1释放的作用 ;I -93对AGEP灭活NO的作用有剂量依赖性抑制效应。结论 :I -93有抑制ASMC增殖的作用 ;对AGEP诱导的BAEC释放ET 1和NO间平衡失调有调节作用 ,在防治阻塞性血管疾病方面I -93具有潜在的应用价值 相似文献
62.
目的:探讨彩超检测高血脂患者颈动脉内膜-中膜厚度及斑块形成的意义,方法:medison-8000Ex高频超声对120例高血脂患者及120例血脂正常者两组,观察其动脉的内膜-中膜厚度及斑块形成情况。结果:血脂升高组,颈总动脉最大内膜-中膜厚度及粥样斑块发生率明显增高。结论:彩超可清晰显示颈动脉内膜-中膜情况,对高血脂引起的动脉粥样硬化检出预报和疗效观察有重要临床意义。 相似文献
63.
Quantification of atherosclerotic plaque components using in vivo MRI and supervised classifiers. 总被引:5,自引:0,他引:5
J M A Hofman W J Branderhorst H M M ten Eikelder V C Cappendijk S Heeneman M E Kooi P A J Hilbers B M ter Haar Romeny 《Magnetic resonance in medicine》2006,55(4):790-799
In this work we aimed to study the possibility of using supervised classifiers to quantify the main components of carotid atherosclerotic plaque in vivo on the basis of multisequence MRI data. MRI data consisting of five MR weightings were obtained from 25 symptomatic subjects. Histological micrographs of endarterectomy specimens from the 25 carotids were used as a standard of reference for training and evaluation. The set of subjects was divided in a training set (12 subjects) and an evaluation set (13 subjects). Four different classifiers and two human MRI readers determined the percentages of calcified tissue, fibrous tissue, lipid core, and intraplaque hemorrhage on the subject level for all subjects in the evaluation set. Quantification of the relatively small amounts of calcium could not be done with statistical significance by either the classifiers or the MRI readers. For the other tissues a simple Bayesian classifier (Bayes) performed better than the other classifiers and the MRI readers. All classifiers performed better than the MRI readers in quantifying the sum of hemorrhage and lipid proportions. The MRI readers overestimated the hemorrhage proportions and tended to underestimate the lipid proportions. In conclusion, this pilot study demonstrates the benefits of algorithmic classifiers for quantifying plaque components. 相似文献
64.
Jonathan Rosman Michael Shapiro Anuragini Pandey Andrew VanTosh Steven R. Bergmann 《Journal of nuclear cardiology》2006,13(3):333-337
BACKGROUND: Coronary artery calcium (CAC) provides evidence of coronary atherosclerosis and has significant prognostic power. Although prior studies have documented a relationship between CAC and hemodynamically significant coronary artery stenosis, the results have not been conclusive. METHODS AND RESULTS: We evaluated 126 consecutive patients who underwent electron beam computed tomography CAC scoring by use of the Agatston method and stress myocardial perfusion imaging (MPI) within 3 months of each other. The analysis revealed no correlation between absolute CAC score and age- and gender-adjusted CAC scores with MPI. Overall, 18% of patients had abnormal MPI results irrespective of their CAC. CONCLUSION: CAC scoring and stress MPI should be thus considered complementary approaches rather than exclusionary in the evaluation of the patient at risk for coronary artery disease. 相似文献
65.
目的 了解二尖瓣环钙化(MAC)与颈动脉粥样硬化之间的关系,探讨MAC能否作为颈动脉粥样硬化的独立预测因子。方法 采用高频超声对156例MAC患者(其中55例为重度MAC患者)及118例年龄、性别与之相匹配的无MAC对照者的颈动脉进行了检测。结果 ①与对照组比较,MAC组及重度MAC组患者高血压和糖尿病的患病率明显增加(P〈0.05);②MAC组颈动脉粥样硬化斑块发生率,颈动脉狭窄≥20%、≥40%及双侧颈动脉狭窄≥40%的发生率均显著高于对照组(P〈0.01),重度MAC组上述指标的改变更为显著(P〈0.01)。此外,重度MAC组颈动脉狭窄≥60%的发生率明显高于对照组(P〈0.05);③MAC组及重度MAc组颈动脉内-中膜厚度(IMT)显著高于对照组(P〈0.01);④单因素及多因素Logistic回归分析结果均表明:MAC是颈动脉狭窄≥40%最有意义的预测因子(P〈0.01)。结论 MAC与颈动脉粥样硬化之间存在十分密切的关系,通过对MAC的检测,能够预测颈动脉粥样硬化的存在及其程度,在临床实际工作中,对于有二尖瓣环钙化的患者应常规进行颈动脉粥样硬化的检查。 相似文献
66.
我们用食饵性高血脂加异种血清反复静脉注射造成动脉内皮免疫性损伤的方法,建立了兔实验性动脉粥样硬化模型,观察了中药川芎对脑血管血液动力学参数(CVHP)的影响。发现川芎组CVHP各项指标均与正常对照组接近,与正常组比较,无显著性差异,颈动脉平均血流量(Qmean)、平均血流速度(Vmean)、最小血流速度(Vmin)、脑血管零压顺应性(CO)和脑血管外周阻力(R)等指标显著优于动脉粥样硬化组(P<0.05~0.01)。本实验结果提示川芎对脑血管功能具有保护作用。 相似文献
67.
目的 探讨冠心病患者与颈动脉粥样硬化之间的发生关系。方法 主要应用彩色多普勒超声技术检测 10 2例冠心病患者的颈动脉 ,对其中 34例进行冠状动脉造影检查。结果 为各组冠心病患者颈动脉管壁内 -中膜厚度 ,斑块指数均显著增高 ,其中心肌梗死患者伴有明显的血流参数异常 ,34例患者冠状动脉造影与颈动脉超声检查符合率为 75 % ,而且冠状动脉病变越重 ,颈动脉硬化发生率越高。结论 颈动脉粥样硬化程度可间接反映冠状动脉病变程度。 相似文献
68.
Petru Liuba Jerker Persson Jukka Luoma Seppo Yl?-Herttuala Erkki Pesonen 《European heart journal》2003,24(6):515-521
BACKGROUND: Atherosclerosis begins early in life. Infections might contribute to the pathogenesis of atherosclerosis. In this study, we investigated whether acute infections in children could alter the carotid wall morphology and the lipid profile. METHODS: Mean carotid intima-media thickness (IMT) was measured by high-resolution ultrasound in 28 hospitalised children (mean age: 5+/-2 years), who fulfilled the diagnostic criteria of acute infections (body temperature, >38 degrees C; C-reactive protein, >15mg/ml, and clinical), and in 20 age- and gender-matched controls. Antibodies against oxidised low-density lipoprotein (anti-oxLDL antibodies), as well as total and high-density lipoprotein cholesterol (HDL-C) were analysed in all children. The infection group was investigated both during the acute illness and 3 months after clinical recovery (post-infection). RESULTS: During the acute illness, the infection group had elevated anti-oxLDL antibodies and decreased HDL-C, as compared to those obtained at 3 months and in controls (p<0.05). These changes in the infection group were followed, at 3 months, by thickening of carotid intima-media. Those who received antibiotics during their acute illness had less carotid thickening than those who were not treated with antibiotics (p<0.05). CONCLUSION: Acute infections in children seem to be accompanied by enhanced oxidative modification of LDL and by decrease in HDL-C. These lipid changes may be followed by thickening of carotid artery intima-media. These findings suggest that, in childhood, acute infections could be associated with increased risk of atherosclerosis, and warrant further studies on this topic. 相似文献
69.
颈动脉分叉血液动力状态的计算流体力学初步研究 总被引:3,自引:2,他引:1
目的应用计算流体力学(CFD)方法结合血管影像显示在体颈动脉分叉的血流动力状态.方法选取1例志愿者,采用Siemens多层螺旋CT机行左侧颈动脉CT血管成像检查(CTA),扫描所得原始图像经计算机后处理后,用CFD方法计算并显示血液动力学各项指标.结果(1)该血管血液流率均值范围为0.04~0.36 m/s,颈外和颈内动脉的内侧壁(均以分叉顶点为参照)可见一高血流速区,球部可见较大片低血流速区;颈动脉分叉及颈内、外动脉近端均可见血液涡流与回流.(2)血液绝对压、静态压和动态压的均值范围分别为100 266.70~101 615.90 Pa、-10 58.34~290.88 Pa、6.12~553.25 Pa;(3)管壁切应力均值范围为0.59~5.35 Pa,在颈动脉球部及颈内动脉后壁显示大范围的低切应力区,最低约为0.25 Pa,颈外动脉前外侧壁存在一小范围低切应力区.结论CFD方法结合血管影像能计算并显示在体颈动脉分叉的个体化血液动力学指标. 相似文献
70.
Balloon occlusion of the internal carotid artery in 40 cases of giant intracavernous aneurysm: technical aspects,cerebral monitoring,and results 总被引:13,自引:2,他引:11
V. Vazquez Añon A. Aymard Y. P. Gobin A. Casasco D. Rüffenacht M. H. Khayata E. Abizanda A. Redondo J. J. Merland 《Neuroradiology》1992,34(3):245-251
Summary We have studied the results of carotid occlusion in the treatment of giant intracavernous carotid artery (ICA) aneurysms in 40 patients. Clinical, angiographic, Doppler and cerebral blood flow (CBF) criteria for tolerance of occlusion are discussed. The patients had headaches (47.5%), cranial nerve compression (87.5%), decreased visual acuity (20%), ruptured aneurysm (15%) and 5% were asymptomatic. Balloon occlusion tests were performed under light sedation anaesthesia: a successful test required perfect clinical tolerance and adequate angiographic collateral circulation in arterial, parenchymatous, and venous phases. Additional criteria include xenon 133 CBF measurements, and transcranial Doppler sonography of the middle cerebral artery. According to these criteria, 5 patients did not tolerate test occlusion and required an extra-intracranial (EC-IC) bypass. Mean follow-up was 4.7 years. All patients were radiologically cured of their ancurysm, and in 35 the symptoms resolved, although 3 had persistent ocular motor nerve palsies, and in 4 visual defects were unchanged. Complications were 1 permanent and 3 transient neurological deficits. Balloon occlusion of the ICA is an effective, reliable form of treatment for intracavernous giant aneurysm and should replace surgical ligation of the cervical carotid artery. With CBF or Doppler monitoring, the risk of neurological deficit is diminished. EC-IC bypass prior to ICA occlusion is indicated if test occlusion is not tolerated. 相似文献