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   160篇
  免费   13篇
  国内免费   45篇
耳鼻咽喉   5篇
儿科学   13篇
妇产科学   5篇
基础医学   23篇
口腔科学   3篇
临床医学   40篇
内科学   25篇
皮肤病学   2篇
神经病学   15篇
特种医学   12篇
外科学   6篇
综合类   8篇
一般理论   1篇
预防医学   11篇
眼科学   1篇
药学   20篇
肿瘤学   28篇
  2022年   1篇
  2021年   3篇
  2020年   1篇
  2019年   2篇
  2018年   5篇
  2017年   4篇
  2016年   6篇
  2015年   8篇
  2014年   6篇
  2013年   6篇
  2012年   8篇
  2011年   7篇
  2010年   4篇
  2009年   8篇
  2008年   10篇
  2007年   35篇
  2006年   11篇
  2005年   11篇
  2004年   3篇
  2003年   9篇
  2002年   7篇
  2001年   10篇
  2000年   14篇
  1999年   2篇
  1998年   11篇
  1997年   1篇
  1996年   3篇
  1995年   3篇
  1994年   2篇
  1993年   3篇
  1992年   2篇
  1991年   2篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1979年   1篇
排序方式: 共有218条查询结果,搜索用时 15 毫秒
1.
亮氨酸脑啡肽的电子结构及构效关系研究   总被引:1,自引:0,他引:1  
对亮氨酸脑啡肽进行了量子化学(INDO)计算,研究其电子结构特征,讨论其活性部位、作用机理及构效关系。同吗啡和R31833进行了活性部位的电子结构与空间结构比较,推断它们的活性药效结构具有共同特点,与阿片受体相互作用时作用方式相同,作用部位有对应关系,因而具有相同的药理性质。  相似文献   
2.
ObjectivesUnderstanding the level of investment needed for the 2021-2030 decade is important as the global community faces the next strategic period for vaccines and immunization programs. To assist with this goal, we estimated the aggregate costs of immunization programs for ten vaccines in 94 low- and middle-income countries from 2011 to 2030.MethodWe calculated vaccine, immunization delivery and stockpile costs for 94 low- and middle-income countries leveraging the latest available data sources. We conducted scenario analyses to vary assumptions about the relationship between delivery cost and coverage as well as vaccine prices for fully self-financing countries.ResultsThe total aggregate cost of immunization programs in 94 countries for 10 vaccines from 2011 to 2030 is $70.8 billion (confidence interval: $56.6-$93.3) under the base case scenario and $84.1 billion ($72.8-$102.7) under an incremental delivery cost scenario, with an increasing trend over two decades. The relative proportion of vaccine and delivery costs for pneumococcal conjugate, human papillomavirus, and rotavirus vaccines increase as more countries introduce these vaccines. Nine countries in accelerated transition phase bear the highest burden of the costs in the next decade, and uncertainty with vaccine prices for the 17 fully self-financing countries could lead to total costs that are 1.3-13.1 times higher than the base case scenario.ConclusionResource mobilization efforts at the global and country levels will be needed to reach the level of investment needed for the coming decade. Global-level initiatives and targeted strategies for transitioning countries will help ensure the sustainability of immunization programs.  相似文献   
3.
As the mortality of pediatric cancers has decreased, focus on neuropsychological morbidities of treatment sequelae have increased. Neuropsychological evaluations are essential diagnostic tools that assess cognitive functioning and neurobiological integrity. These tests provide vital information to support ongoing medical care, documenting cognitive morbidity and response to interventions. We frame standards for neuropsychological monitoring of pediatric patients with CNS malignancy or who received cancer‐directed therapies involving the CNS and discuss billing for these services in the United States in the context of clinical research. We describe a cost‐effective, efficient model of neuropsychological monitoring that may increases access to neuropsychological care. Pediatr Blood Cancer © 2015 Wiley Periodicals, Inc.  相似文献   
4.
目的:神经断端保留小间隙的静脉桥接模拟神经外膜形成神经再生室,为周围神经再生创造了良好的生理环境,从而保证神经束的良好对合。实验采用部分脱乙酰甲壳质作为套管材料,用小间隙桥接方法修复坐骨神经损伤,观察套管内的神经再生情况,并与传统外膜缝合法进行比较。方法:实验于2001-01/2002-10在北京大学人民医院创伤骨科实验室完成。①主要材料:实验所用中空圆柱形套管为北京大学人民医院与中国纺织科学院共同发明的一种部分脱乙酰甲壳质生物套管(专利号:01136314.2)。实验中所用套管尺寸为:管长4 mm,壁厚0.1 mm,内径1.5 mm。②实验动物:健康成年雄性SD大鼠20只,随机分成2大组,每组10只,每一大组全部10只动物的左腿坐骨神经为一组,右腿坐骨神经为另一组,每组10根坐骨神经。另取5只同样大鼠双侧坐骨神经未做处理作为正常对照组。③实验方法:外膜原位缝合组:切断坐骨神经,显微镜下神经外膜原位缝合;生物套管小间隙原位桥接组:切断坐骨神经,显微镜下小间隙套管桥接;断端旋转180°外膜缝合组:切断坐骨神经,显微镜下远端旋转180°后,神经外膜缝合;断端旋转180°生物套管小间隙桥接组:切断坐骨神经,显微镜下远端旋转180°后,小间隙套管桥接。④实验评估:术后第7,14,21,28,42天取坐骨神经,进行免疫组织化学染色及观察。结果:再生神经延套管中央走行,7 d时已有部分纤维通过2 mm间隙,14 d时有髓纤维数量明显多于近端。21 d后,套管组与原位外膜组新生有髓神经纤维数相近。再生纤维胞核数量较多,髓鞘纤细。套管结构完整。结论:此种部分脱乙酰甲壳质生物套管内的再生神经连续、整齐,髓鞘完整,其神经再生情况好于传统外膜缝合法。  相似文献   
5.
Bédard JP  Blais C  Patenaude YG  Monga E 《Radiology》2005,234(3):929-933
PURPOSE: To prospectively evaluate contrast enhancement on pulmonary computed tomographic (CT) angiograms obtained by using an iso-osmolar versus a low-osmolarity contrast agent to exclude pulmonary embolism. MATERIALS AND METHODS: Written patient consent was obtained on a form approved by the institutional review board, and the board approved the study. This prospective, randomized, double-blinded clinical trial included 47 patients referred for multi-detector row CT angiography to exclude pulmonary embolism over a 5-month period. Patients received either iohexol or iodixanol as an intravenous contrast agent. Three radiologists independently evaluated enhancement homogeneity and quality in designated pulmonary artery branches at four consecutive levels in the lower lobe of the left lung from lobar to subsegmental arteries. This evaluation was performed at a workstation separately for homogeneity and quality with two different three-level scales established with consensus. Percentages of each given score were compared with the chi2 test. The mean attenuation (expressed in Hounsfield units) for each contrast agent was compared with Student t test, and interobserver agreement (kappa value) was calculated. RESULTS: The percentages of arteries graded as excellent or not diagnostic were not statistically different (P >.05), with comparison of the two contrast agents at all levels. The intensity of enhancement (quantitative evaluation of enhancement by using mean attenuation of vessel lumen) was similar (P >.05) in the two groups. The kappa values varied from 0.35 to 0.56 among readers. CONCLUSION: Use of an iso-osmolar contrast agent at multi-detector row CT angiography to exclude pulmonary embolism did not significantly improve enhancement quality when this feature was compared with that of a low-osmolarity contrast agent.  相似文献   
6.
OBJECTIVE: The aim of the study was to evaluate the efficacy of ultrasonography and videobronchoscopy in measuring the subglottic diameter in the paediatric population. DESIGN: A double-blinded, prospective clinical study carried out at the Montreal Children's Hospital, McGill University. METHODS: Children undergoing non-life-threatening bronchoscopy for various reasons had the subglottic diameters measured with ultrasonography, videobronchoscopy, and the traditional method of endotracheal tube sizing during the operative period. Ten patients were enrolled in the study. Parental consent was obtained prior to the procedure. RESULTS: Statistical analysis revealed that although ultrasonography was highly correlated with both videobronchoscopy and endotracheal tube sizing in measuring the subglottic diameter in the paediatric population, the measurements were not accurate in giving an exact value of the diameters in question. Videobronchoscopy was found to highly correlate with endotracheal tube sizing but had values that were slightly larger. CONCLUSION: This study is the first to examine the ability of ultrasonography and videobronchoscopy in evaluating the subglottic diameter in the paediatric population. Videobronchoscopy was shown to correlate highly with the present standard of measurement, namely, endotracheal tube sizing. The difference in measurement between the two was shown to be statistically significant, with videobronchoscopy being the consistently larger of the two. These results are in keeping with the limitations of measurement by the endotracheal tube. Similarly, ultrasonography was also correlated with both videobronchoscopy and endotracheal tube sizing. In contrast, ultrasonography was found to provide measurements that were significantly smaller than the other two methods. This suggests that ultrasonography may be a good technique to follow the change in lesions of the subglottis but may be poor for absolute measurements of this area as it always underestimated the size of the lumen.  相似文献   
7.
8.
目的:分析代谢综合征患者大网膜脂肪组织胰岛素受体底物1、葡萄糖转运蛋白4和抵抗素mRNA表达水平及其与代谢综合征相关指标的关系。方法:选择2003-02/08在青岛大学医学院附属医院普通外科及妇科择期手术的患者53例,均知情同意。根据代谢综合征的诊断标准分为两组:①代谢综合征组28例,分为两个亚组:2型糖尿病组13例,非糖尿病组15例。②对照组25例。手术前当天抽取患者空腹血,测定空腹血糖、三酰甘油、空腹胰岛素。手术中取大网膜脂肪组织约200mg,用于RNA提取。采用一步法半定量反转录聚合酶链反应技术,测定患者大网膜脂肪组织中胰岛素受体底物1、葡萄糖转运蛋白4以及抵抗素的mRNA表达水平。结果:代谢综合征组28例,对照组25例患者全部进入结果分析,无脱落。①代谢综合征组患者大网膜脂肪组织胰岛素受体底物1、葡萄糖转运蛋白4mRNA表达均显著低于对照组(P<0.01)。2型糖尿病患者的胰岛素受体底物1mRNA、葡萄糖转运蛋白4mRNA表达显著低于非糖尿病患者(P<0.01)。②代谢综合征组与对照组患者胰岛素受体底物1与葡萄糖转运蛋白4的mRNA表达呈显著正相关(r=0.661,0.621,P<0.01)。③多因素逐步回归分析显示腰臀比与胰岛素抵抗指数及胰岛素受体底物1、葡萄糖转运蛋白4mRNA表达均有明显的相关性。④抵抗素mRNA表达阳性率和表达量在2型糖尿病代谢综合征患者、非糖尿病代谢综合征患者与对照组之间差异均无显著性意义(P=0.121,P=0.228),与腰臀比、体质量指数、胰岛素抵抗指数、空腹血糖、空腹胰岛素、三酰甘油以及血压均无相关性(P>0.05)。结论:代谢综合征患者大网膜脂肪组织胰岛素受体底物1与葡萄糖转运蛋白4mRNA表达明显降低,其中以2型糖尿病患者表现最为显著。大网膜脂肪组织抵抗素mRNA表达与代谢综合征及2型糖尿病无关。胰岛素受体底物1、葡萄糖转运蛋白4的mRNA表达和腰臀比可联合预测胰岛素抵抗的程度。  相似文献   
9.
目的:为获得组织工程化自体血管,观察体外静态培养条件下犬内皮细胞与平滑肌细胞联合培养组织学及形态学的特征。方法:实验于2004-07/2005-06在首都医科大学宣武医院外科院级实验室完成。①实验材料:雄性杂种犬,3个月龄,体质量8~12kg。②实验方法:贴块法及酶解法对犬内皮细胞及平滑肌细胞进行原代分离培养及扩增,将第Ⅱ代平滑肌细胞以1×109L-1的密度种植于胶原膜上培养13d,再将第Ⅱ代内皮细胞接种于生长平滑肌细胞的胶原膜上2d。③实验评估:行苏木精-伊红染色同时扫描电镜和透射电镜观察平滑肌细胞和内皮细胞在胶原载体上联合培养后的形态。结果:苏木精-伊红染色见平滑肌细胞较均匀的分布于支架材料表面及内部;扫描电镜下,平滑肌细胞可以在胶原载体材料上生长,增殖明显并在短期内形成多层细胞。内皮细胞与平滑肌细胞联合培养2d就可在平滑肌细胞层表面获得连续的单层内皮细胞层。结论:在短期静态培养条件下犬的血管平滑肌细胞和内皮细胞可以在胶原载体材料上形成具有两层细胞结构的组织工程化动脉血管组织片。  相似文献   
10.
关节部位Ⅲ度烧伤削痂植皮与切痂植皮的效果比较   总被引:3,自引:0,他引:3  
目的:Ⅲ度烧伤创面的处理临床上仍然以切痂植皮术治疗为主,由于切痂时切除了并未损伤的皮下脂肪组织,使其愈后外观变化明显。实验拟观察关节部位Ⅲ度烧伤削痂后于脂肪层移植大张自体中厚皮的疗效,并与切痂植皮进行比较。方法:①于2001-01/2007-06南昌大学第一附属医院烧伤科收治的关节Ⅲ度烧伤患者中抽取39例(45个关节)作为削痂组,同时抽取45例(共60个关节)作为切痂组。所有患者对治疗及实验方案均知情同意,且得到医院伦理道德委员会批准。②削痂组削痂植皮,保留正常皮下脂肪等组织。切痂组切痂植皮,切痂平面包括全层皮肤和皮下脂肪组织一并切除直至深筋膜层。削痂或切痂后植大张自体中厚皮。③创面修复后4 ̄6周观察两组患者的关节外观和关节活动功能;比较两组患者术后2周的植皮成活率和创面修复时间。结果:两组患者均进入结果分析。①两组患者烧伤关节创面修复后与对称的正常关节比较,削痂组外观变化不明显,周径缩小3.6%(P>0.05),功能好,关节活动度减少5.3%(P>0.05);切痂组外观变化明显,周径缩小23.4%(P<0.05),功能较差,关节活动度减少21.9%(P<0.05)。②两组患者术后2周植皮成活率和创面修复时间差异均无显著性意义(P>0.05)。结论:脂肪层移植大张自体中厚皮于Ⅲ度烧伤削痂后关节部位,能够维护肢体的美观,保护关节功能,疗效优于切痂植皮。  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