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   293篇
  免费   19篇
  国内免费   13篇
耳鼻咽喉   9篇
儿科学   23篇
妇产科学   1篇
基础医学   21篇
口腔科学   6篇
临床医学   25篇
内科学   68篇
皮肤病学   4篇
神经病学   21篇
特种医学   66篇
外科学   12篇
综合类   8篇
预防医学   10篇
药学   32篇
中国医学   1篇
肿瘤学   18篇
  2023年   1篇
  2021年   1篇
  2020年   3篇
  2019年   3篇
  2018年   3篇
  2017年   3篇
  2016年   2篇
  2015年   6篇
  2014年   4篇
  2013年   4篇
  2012年   2篇
  2011年   7篇
  2010年   12篇
  2009年   15篇
  2008年   5篇
  2007年   11篇
  2006年   5篇
  2005年   8篇
  2004年   8篇
  2003年   8篇
  2002年   4篇
  2001年   4篇
  2000年   4篇
  1999年   3篇
  1998年   17篇
  1997年   14篇
  1996年   12篇
  1995年   11篇
  1994年   17篇
  1993年   13篇
  1992年   5篇
  1991年   7篇
  1990年   18篇
  1989年   15篇
  1988年   9篇
  1987年   10篇
  1986年   6篇
  1985年   5篇
  1984年   5篇
  1983年   6篇
  1982年   4篇
  1981年   6篇
  1980年   5篇
  1979年   1篇
  1978年   6篇
  1977年   3篇
  1976年   4篇
排序方式: 共有325条查询结果,搜索用时 11 毫秒
61.
目的:利用组织工程原理探讨修复全层皮肤缺损的理想方式。方法:以裸鼠为动物模型,在皮肤全层缺损区域分别移植纤维蛋白胶(n=10),纤维蛋白胶角质细胞悬液(n=10),纤维蛋白胶成纤维细胞悬液(n=10)以及纤维蛋白胶角质细胞成纤维细胞悬液(n=10),术后每天对伤口进行大体观察,第5,7,10,14,21,35d,分别取材活检行组织学及免疫组织化学检查。结果:移植有角质细胞组(2和4组)的创面愈合快,术后10d组织学提示创面完全上皮化,抗人特异性HLA-1型抗原、抗involucrin染色和抗Ⅶ型胶原染色阳性证明新生上皮由移植的人角质细胞形成,抗involucrin染色阳性又证明角质细胞分化成熟有角质层形成,抗Laminin染色、抗Ⅶ型胶原染色阳性提示早期基底膜形成。组织学检查提示第4组新生上皮有许多类似皮钉样结构。结论:培养的角质细胞,成纤维细胞结合纤维蛋白胶移植到创面上后,可以形成复层分化良好、接近正常结构和功能的新生成肤组织。  相似文献   
62.
63.
64.
The difficulties arising from association analysis with rare variants underline the importance of suitable reference population cohorts, which integrate detailed spatial information. We analyzed a sample of 1684 individuals from Western France, who were genotyped at genome-wide level, from two cohorts D.E.S.I.R and CavsGen. We found that fine-scale population structure occurs at the scale of Western France, with distinct admixture proportions for individuals originating from the Brittany Region and the Vendée Department. Genetic differentiation increases with distance at a high rate in these two parts of Northwestern France and linkage disequilibrium is higher in Brittany suggesting a lower effective population size. When looking for genomic regions informative about Breton origin, we found two prominent associated regions that include the lactase region and the HLA complex. For both the lactase and the HLA regions, there is a low differentiation between Bretons and Irish, and this is also found at the genome-wide level. At a more refined scale, and within the Pays de la Loire Region, we also found evidence of fine-scale population structure, although principal component analysis showed that individuals from different departments cannot be confidently discriminated. Because of the evidence for fine-scale genetic structure in Western France, we anticipate that rare and geographically localized variants will be identified in future full-sequence analyses.  相似文献   
65.
66.
BACKGROUND: Since the mid-1980s, blood banks in the United States have screened donors for elevated alanine aminotransferase (ALT) in an effort to prevent posttransfusion hepatitis. The present study was designed to quantitate the residual value of ALT screening following the implementation of hepatitis C virus (HCV) assays. STUDY DESIGN AND METHODS: Two approaches were used. First, a database of 2.3 million donations made by 586,507 volunteer blood donors between 1991 and 1993 was used to compare the incidence of seroconversion to hepatitis B virus (HBV) and HCV marker positivity in donors with elevated ALT values and with normal ALT values. Second, the duration of ALT elevation prior to HBV and HCV seroconversion was determined from 34 well-documented cases of posttransfusion HBV and HCV; elevated-ALT window periods were multiplied by rates of HBV and HCV incidence in donors to project the yield of ALT screening. Predictive value and cost- effectiveness analyses were also performed to compare the value of ALT screening before and after HCV screening was implemented. RESULTS: Both approaches indicate that ALT testing does not detect HBV in the window phase but does currently identify approximately 3 HCV window-phase donations per 1 million donations; this contrasts with ALT detection of approximately 1800 HCV-infectious units per 1 million donations prior to anti-HCV screening. Currently, only 8 in 10,000 donated units with elevated ALT (negative anti-HCV) are infected with HCV. The cost of continued ALT screening was estimated at $7,931,000 per quality- adjusted year of life saved. CONCLUSION: The yield, predictive value, and cost-effectiveness of ALT screening of blood donors have declined dramatically with the implementation of progressively improved anti-HCV assays. ALT screening of volunteer blood donors should be discontinued.  相似文献   
67.
68.
69.
It is the purpose of the study to report the frequency of parvovirus in children with a diagnosis of Diamond-Blackfan anaemia and to discuss the possible aetiological role of parvovirus in Diamond-Blackfan anaemia. We found parvovirus DNA in 3 of 11 bone marrow smears. Giant pronormoblasts showed low sensitivity (33%) and poor specificity (75%). The presence of giant pronormoblasts was associated with a very high myeloid: erythroid ratio, and may not be specific for parvovirus infection, but a feature of severely suppressed erythropoiesis. The three parvovirus-positive patients were the only children who experienced a remission, and who are free of medication. The seven surviving parvovirus-negative patients are all currently on steroid treatment.  相似文献   
70.
The role of D1 receptors in motor control is poorly understood. In parkinsonian squirrel monkeys, the full D1 agonist C-APB (SKF 82958; 0.1-0.4 mg/kg s.c.) caused weak stimulation of locomotor activity. However, the motor stimulant effects of the D2 agonist (+)-PHNO (0.001 mg/kg s.c.) were not potentiated by C-APB (0.3 mg/kg). Differences between these observations and expectations from experiments using rodents are discussed.  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