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   272篇
  免费   12篇
  国内免费   50篇
耳鼻咽喉   1篇
儿科学   3篇
妇产科学   1篇
基础医学   64篇
口腔科学   6篇
临床医学   40篇
内科学   32篇
皮肤病学   3篇
神经病学   20篇
特种医学   19篇
外科学   21篇
综合类   29篇
预防医学   10篇
眼科学   4篇
药学   57篇
肿瘤学   24篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2018年   2篇
  2017年   3篇
  2016年   4篇
  2015年   11篇
  2014年   10篇
  2013年   6篇
  2012年   12篇
  2011年   11篇
  2010年   21篇
  2009年   17篇
  2008年   15篇
  2007年   42篇
  2006年   19篇
  2005年   19篇
  2004年   7篇
  2003年   5篇
  2002年   3篇
  2001年   6篇
  2000年   3篇
  1999年   3篇
  1998年   16篇
  1997年   21篇
  1996年   8篇
  1995年   9篇
  1994年   10篇
  1993年   10篇
  1992年   5篇
  1991年   9篇
  1990年   3篇
  1989年   5篇
  1988年   5篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1983年   1篇
  1976年   4篇
  1975年   1篇
排序方式: 共有334条查询结果,搜索用时 15 毫秒
31.
32.
BACKGROUND: Quality of life (QOL) assessment has emerged to measure and quantify the balance between treatment benefit and toxicity, and has a value in predicting response and overall survival in cancer patients. METHODS: From July 1995 to February 1997, 38 symptomatic patients with advanced non-small cell lung cancer (NSCLC) were treated with MIP chemotherapy (mitomycin 6 mg/m2, ifosfamide 3000 mg/m2 and cisplatin 50 mg/m2 on day 1 every 3 weeks). Patients were assessed for QOL including physical well-being, general symptoms and lung cancer-specific symptoms, as well as objective response. RESULTS: The overall response rate was 38.9% (14/36, all were partial response) and the median duration of response was 3.5 months [95% confidence interval (CI) 2.0-4.0]. The median duration of overall survival was 7 months (95% CI 5.9-8.5). The overall improvement of QOL was 58.3% with 21 patients feeling better on treatment. The toxicity of chemotherapy was mild, mainly nausea/vomiting and minimal alopecia. Using multiple clinical predictors of survival (age, histology, stage, performance status), only change of QOL emerged significantly (P = 0.0007). CONCLUSIONS: MIP had an endurable response and low toxicity profile, and provided good QOL. Integral QOL data in our study provided the strong prediction of survival in advanced NSCLC. Further experienced QOL study will provide greatly enhanced outcome data in clinical trials.   相似文献   
33.
OBJECTIVE: Despite the identification of mutations in the connexin 26 (GJB2) gene as the most common cause of recessive nonsyndromic hearing loss, the pattern of hearing impairment with these mutations remains inconsistent. Recently a deletion encompassing the GJB6 gene was identified and hypothesized to also contribute to hearing loss. We hereby describe the hearing impairment in Dutch patients with biallelic connexin 26 (GJB2) and GJB2+connexin 30 (GJB6) mutations. METHODS: The audiograms of patients who were screened for GJB2 and GJB6 mutations were analysed retrospectively. Standard statistical testing was done for symmetry and shape, while repeated measurement analysis was used to assess the relation between mutation and severity. Progression was also studied via linear regression analysis. RESULTS: Of 222 hearing-impaired individuals, 35 exhibited sequence variations; of these 19 had audiograms for study. Hearing loss in patients with biallelic "radical" (i.e. deletions, nonsense and splice site) mutations was significantly worse than in the wild type and heterozygotes (SAS proc GENMOD, p=0.013). The presence of at least one missense mutation in compound heterozygotes tends to lead to better hearing thresholds compared to biallelic radical mutations (p=0.08). One patient with the [35delG]+[del(GJB6-D13S1830)] genotype was severely impaired. Non-progressive hearing impairment was demonstrated in five 35delG homozygotes in individual longitudinal analyses. However a patient with the [299A>C]+[416G>A] genotype showed significant threshold progression in the lower frequencies. Findings on asymmetry and shape were inconclusive. CONCLUSIONS: Our data support the hypothesis that severity is a function of genotype and its effect on the amino acid sequence. A bigger cohort is required to establish non-progressivity more definitively.  相似文献   
34.
35.
本文报告了用电化学检测器的高效液相色谱法测定血清及尿中速尿含量的方法。样品予处理方法:血清用乙腈除蛋白,尿用蒸馏水稀释50倍。采用作者合成的FD-Val-OH作为内标物。色谱条件为:反相柱,以含35%乙醇的5mmol/L四丁基铵水溶液为流动相(pH7.50),流速1.0ml/min;用电化学检测器,检测电压0.90V:速尿及内标物的保留时间分别为10和15min。通过计算速尿对内标物的峰高比求得速尿含量。血清及尿中的最低检测浓度分别为16和9ng/ml。标准曲线在0.25~5ng/μl(血清)、0.5~10ng/μl(尿)的浓度范围内呈线性关系。血清及尿中回收率分别为100.5%和100.6%。变异系数在4.6%以下。  相似文献   
36.
目的:了解丹参酮ⅡA对神经祖细胞系C17.2的保护作用,探讨其可能的作用机制。方法:本实验于2005年起在广州血液中心器官移植配型中心实验室进行。C17.2祖细胞系由澳大利亚新南威尔士大学解剖教研室David Walsh博士惠赠。将C17.2细胞以1×109L-1的密度接种,用含10%胎牛血清IMDM,37℃、体积分数为0.05CO2、饱和湿度的CO2培养箱培养,接近融合的C17.2细胞用含0.1mmol/LEDTA的胰酶室温消化,按1∶3的比例传代。C17.2细胞以5×107L-1的密度接种于96孔板或25cm2的培养瓶中,用含10%胎牛血清IMDM培养过夜后,加入含4g/L AAPH(水溶性偶氮引发剂2,2'-偶氮二(2-脒基丙烷)二盐酸盐)无血清的IMDM培养基培养建立神经细胞凋亡模型。C17.2细胞以5×103/孔的密度接种于96孔板中,用含10%胎牛血清IMDM培养过夜后,加入含4g/LAAPH无血清的IMDM培养基培养。对照组不加入丹参酮ⅡA,实验组分别加入0.02,0.05,0.1,0.2mg/L丹参酮ⅡA培养8h,噻唑蓝法检测细胞活性:细胞活性的相对值=(实验组吸光度值/对照组吸光度值)×100%,流式细胞仪检测细胞凋亡。结果:①AAPH处理8h后,C17.2细胞被过氧化损害,大多数细胞失去正常的形态,细胞呈圆形,脱落。加入丹参酮ⅡA后,细胞形态基本保持正常,少数细胞呈圆形。②C17.2细胞在IMDM的培养液中,细胞数量是含4g/L AAPH无血清的IMDM培养基条件下的2.5~3倍。浓度为0.02,0.05,0.1mg/L的丹参酮ⅡA对C17.2细胞有保护作用,质量浓度大于0.2mg/L丹参酮ⅡA对C17.2细胞保护作用降低。③AAPH作用前大部分C17.2细胞的线粒体完整,有少量的早期凋亡细胞和凋亡细胞,AAPH作用后凋亡细胞总数、凋亡细胞明显增加。丹参酮ⅡA处理组可以明显减少早期凋亡细胞。结论:在体外丹参酮ⅡA对神经细胞具有抗凋亡的作用,可以保护神经细胞。  相似文献   
37.
目的:总结胰岛移植过程中胰岛培养的研究现状,为利用胰岛培养准备更多更好的胰岛提供理论依据和技术支持。资料来源:以计算机检索Medline和Pubmed数据库1994-01/2007-01与胰岛培养相关的文章,检索词为“isle,tculture”,限定文章语言种类为English。同时计算机检索CNKI中国全文数据库1994-01/2007-01与胰岛培养相关的文章,检索词为“胰岛,培养”,限定文章语言种类为中文。资料选择:对资料进行初审,纳入标准:①与胰岛培养相关的文章。②1994年以后发表的文章。排除标准:Meta分析类文章。资料提炼:共检索到1384篇与胰岛培养相关的文章,入选33篇。对所检索文章的相关信息加以综合概括,其中关于胰岛培养中基础培养基、培养添加物、培养温度、密度等方面的文章18篇,关于胰岛培养新尝试的文章12篇。资料综合:将胰岛培养后再行移植有一定优势,包括降低免疫原性和为术前准备赢得时间等。目前对于挑选合适培养基及其添加物,调整合适培养温度、培养密度以及保护胰岛的活性等都有了比较深入细致的研究;同时很多学者开始尝试一些新的方法延长胰岛培养时间,改善胰岛功能,包括加入细胞外基质、与其他细胞共培养、选用微重力系统培养以及利用胶囊包裹培养等均显示良好的效果。结论:虽然胰岛培养可能会影响胰岛的活性和功能,但随着对胰岛生理和病理生理特性研究的深入,新的技术方法可将这些影响降到最低。胰岛培养给临床实践带来的便利是其最大的优势,加强胰岛培养的研究与应用有着重要的意义。  相似文献   
38.
心肌梗死大鼠心肌细胞凋亡及磷酸肌酸的干预   总被引:3,自引:0,他引:3  
目的:缺血引起的心肌能量供应不足是心肌细胞凋亡主要的因素之一,观察补充外源性能量磷酸肌酸对缺血心肌细胞凋亡和心功能的影响。方法:实验于2003-04/06在解放军总医院老年心血管病研究所实验室完成。选用SD大鼠50只,按随机数字表法分为3组:①磷酸肌酸组19只,结扎左冠状动脉制作心肌梗死模型,结扎前30min按200mg/kg的剂量腹腔注射磷酸肌酸1次。②缺血对照组21只,心肌缺血方法同磷酸肌酸组,结扎前30min腹腔注射相同体积的50g/L葡萄糖注射液1次。③正常对照组10只,仅在冠状动脉下穿线,不结扎冠状动脉,其余同缺血对照组。结扎冠状动脉6h后,取各组大鼠心脏标本做石蜡切片,缺口末端标记法染色,高倍镜下计数心肌细胞凋亡指数,凋亡指数=凋亡心肌细胞数/心肌细胞总数;取心脏标本前,测左心室收缩压、舒张末压和压力变化速度,并进行组间比较。结果:磷酸肌酸组大鼠造模时死亡9只;缺血对照组造模时死亡10只,造模成功后6h内死亡1只,进入结果分析共30只大鼠,每组10只。①缺血对照组大鼠的左心室舒张末压显著高于正常对照组[(13.9±5.3vs.2.8±3.2)mmHg(P<0.01)],左心室压力变化速度显著低于正常对照组[(705.8±111.7vs.1141.7±94.5)mmHg/s(P<0.01)];磷酸肌酸组大鼠的左心室舒张末压显著低于缺血对照组[(8.9±3.5)mmHg(P<0.05)];左心室压力变化速度显著高于缺血对照组[(841.5±76.1)mmHg/s(P<0.01)];左心室收缩压与缺血对照组差异无显著性意义(P>0.05)。②磷酸肌酸组大鼠的心肌细胞凋亡指数显著低于缺血对照组(0.203±0.054vs.0.278±0.052,P=0.006)。结论:补充外源性能量磷酸肌酸可以减少缺血后心肌细胞凋亡,并改善心功能,磷酸肌酸抑制缺血心肌细胞凋亡可能是改善心肌梗死后心功能的主要作用途径之一。  相似文献   
39.
Different configurations of the Monticelli-Spinelli and Ilizarov external fixation systems were tested to define their mechanical properties. In five configurations the external fixator consisted of rings with tensioned wires (circular), while in one configuration two pairs of the tensioned wires and their correspondent ring were replaced by threaded pins (hybrid). Testing was performed in axial compression, bending and torsion. The results were compared to the characteristics of a selected linear fixator group. Both the circular and the hybrid configurations were non-linear in compression. In bending, circular fixators had a similar pattern in both anteroposterior and oblique loading directions. The bending load-displacement pattern for the hybrid fixators was similar to the linear fixators, higher stiffness in the plane of the pins. Torsion was linear for both circular and hybrid fixators, as for the linear fixators. By combination of wires and pins (hybrid configuration), the mechanical behaviour had characteristics from both linear and circular fixators. It is concluded that the three studied groups own different mechanical performance and can be considered as different types of fixators. While it has been demonstrated that osteogenesis can be achieved independently of the mechanical behaviour of the fixator, this study supports the suggestion that some complications can be related to the mechanical behaviour of the fixator.  相似文献   
40.
Background: This observational study was conducted in a small, 45 bed border static hospital, located in a field area, where no blood bank facilities were available. The present study was conducted to elucidate the blood transfusion practices of this hospital.  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