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   137篇
  免费   7篇
  国内免费   1篇
  2021年   1篇
  2018年   1篇
  2016年   1篇
  2015年   3篇
  2014年   4篇
  2013年   7篇
  2012年   10篇
  2011年   8篇
  2010年   9篇
  2009年   8篇
  2008年   3篇
  2007年   5篇
  2006年   7篇
  2005年   3篇
  2004年   7篇
  2003年   4篇
  2002年   2篇
  2001年   9篇
  2000年   6篇
  1999年   2篇
  1998年   2篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   3篇
  1991年   2篇
  1989年   4篇
  1988年   3篇
  1986年   2篇
  1985年   2篇
  1984年   3篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   3篇
  1978年   5篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1966年   1篇
排序方式: 共有145条查询结果,搜索用时 78 毫秒
21.
The ability of acidic alpha-mannosidases from pig kidney, bovine liver, human urine and placenta, and jack bean to correct the deranged metabolism of cultured skin fibroblasts from manosidosis patients is studied. One cause for the different corrective abilities are, as shown for other systems, the different rates of endocytosis of the enzyme forms into the cells. Besides this, it is demonstrated for the first time, that there are differences in the intracellular corrective activity of the internalized enzymes, which can be explained by different specificities of the enzymes against the storage material.  相似文献   
22.
PurposeThis study examined the reliability of patellar tendon cross sectional area (CSA) measurement using brightness mode ultrasonography.MethodsThe patellar tendon CSA of fourteen participants was examined on two different days and at three different positions (proximal, median and distal). Five trials per day were conducted in each position, replacing the ultrasound probe on every trial. The images were examined by three different and equally experienced observers. We compared the mean of the five trials in each position to examine the day, observer and position effect. Further, Bland and Altman plots, root mean square (RMS) differences and intraclass correlation coefficients (ICC) were calculated.ResultsThere was a significant (p < 0.05) day, observer and position effect on the CSA, while the average ICC was 0.592. The Bland and Altman plots showed that differences between conditions or groups, should be in average lower than 37% or higher than 55% of the patellar tendon CSA to be important for clinical or intervention studies.ConclusionOur findings show low reliability of the method, which resulted from the low clarity and unclear visibility of tissue boundaries in the ultrasound images. Therefore, the measurement of the CSA of the patellar tendon using ultrasound does not provide accurate and reliable results.  相似文献   
23.
The effect of trapidil derivative AR12456 on intracellular cholesterol metabolism was investigated in human hepatoma cell line HepG2. AR12456 enhanced the uptake and degradation of125I-LDL in a dose-dependent manner. The drug inhibited cholesterol synthesis and esterification without affecting cellular cholesterol content and bile acid synthesis; cholesterol efflux was slightly increased. These results show that the inhibition of cholesterol synthesis together with the enhanced expression of LDL receptors may partially explain the hypocholesterolemic activity of compound AR12456.  相似文献   
24.
A model is developed to describe the growth, product formation and enzyme synthesis of the microorganism Thermoanaerobacter thermohydrosulfuricus. It differentiates between extracellular enzymatic starch degradation and the microorganism's constant specific growth rate, combined with the ingestion of maltose and maltotriose (the products of starch cleavage). The formation of growth dependent products like ethanol, acetate and the synthesis of the cell-associated enzyme, amylopullulanase, are formulated with constant yield coefficients. In contrast, both the non-growth dependent product lactate, and extracellular enzyme activity are linked to an intracellular substrate concentration. Most of the parameters used in the model are evaluated from batch culture or literature. The calculated results are compared with experimental data. Keywords: Continuous culture; Thermoanaerobacter thermohydrosulfuricus; Starch; Model  相似文献   
25.
26.

Background

Bacterial DNA containing motifs of unmethylated CpG dinucleotides (CpG-ODN) initiate an innate immune response mediated by the pattern recognition receptor Toll-like receptor 9 (TLR9). This leads in particular to the expression of proinflammatory mediators such as tumor necrosis factor (TNF-α) and interleukin-1β (IL-1β). TLR9 is expressed in human and murine pulmonary tissue and induction of proinflammatory mediators has been linked to the development of acute lung injury. Therefore, the hypothesis was tested whether CpG-ODN administration induces an inflammatory response in the lung via TLR9 in vivo.

Methods

Wild-type (WT) and TLR9-deficient (TLR9-D) mice received CpG-ODN intraperitoneally (1668-Thioat, 1 nmol/g BW) and were observed for up to 6 hrs. Lung tissue and plasma samples were taken and various inflammatory markers were measured.

Results

In WT mice, CpG-ODN induced a strong activation of pulmonary NFκB as well as a significant increase in pulmonary TNF-α and IL-1β mRNA/protein. In addition, cytokine serum levels were significantly elevated in WT mice. Increased pulmonary content of lung myeloperoxidase (MPO) was documented in WT mice following application of CpG-ODN. Bronchoalveolar lavage (BAL) revealed that CpG-ODN stimulation significantly increased total cell number as well as neutrophil count in WT animals. In contrast, the CpG-ODN-induced inflammatory response was abolished in TLR9-D mice.

Conclusion

This study suggests that bacterial CpG-ODN causes lung inflammation via TLR9.  相似文献   
27.
28.
Quantitative trait loci (QTL) affecting carcass and meat quality located on SSC2 were identified using variance component methods. A large number of traits involved in meat and carcass quality was detected in a commercial crossbred population: 1855 pigs sired by 17 boars from a synthetic line, which where homozygous (A/A) for IGF2. Using combined linkage and linkage disequilibrium mapping (LDLA), several QTL significantly affecting loin muscle mass, ham weight and ham muscles (outer ham and knuckle ham) and meat quality traits, such as Minolta-L* and -b*, ultimate pH and Japanese colour score were detected. These results agreed well with previous QTL-studies involving SSC2. Since our study is carried out on crossbreds, different QTL may be segregating in the parental lines. To address this question, we compared models with a single QTL-variance component with models allowing for separate sire and dam QTL-variance components. The same QTL were identified using a single QTL variance component model compared to a model allowing for separate variances with minor differences with respect to QTL location. However, the variance component method made it possible to detect QTL segregating in the paternal line (e.g. HAMB), the maternal lines (e.g. Ham) or in both (e.g. pHu). Combining association and linkage information among haplotypes improved slightly the significance of the QTL compared to an analysis using linkage information only.  相似文献   
29.

Background-  

The innate immune system plays an important role in the recognition and induction of protective responses against infectious pathogens, whilst there is increasing evidence for a role in mediating chronic inflammatory diseases at older age. Despite indications that environmental conditions can influence the senescence process of the adaptive immune system, it is not known whether the same holds true for the innate immune system. Therefore we studied whether age-related innate immune responses are similar or differ between populations living under very diverse environmental conditions.  相似文献   
30.

Background

Although both smoking and respiratory complaints are very common, tools to improve diagnostic accuracy are scarce in primary care. This study aimed to reveal what inflammatory patterns prevail in clinically established diagnosis groups, and what factors are associated with eosinophilia.

Method

Induced sputum and blood plasma of 59 primary care patients with COPD (n = 17), asthma (n = 11), chronic bronchitis (CB, n = 14) and smokers with no respiratory complaints ('healthy smokers', n = 17) were collected, as well as lung function, smoking history and clinical work-up. Patterns of inflammatory markers per clinical diagnosis and factors associated with eosinophilia were analyzed by multiple regression analyses, the differences expressed in odds ratios (OR) with 95% confidence intervals.

Results

Multivariately, COPD was significantly associated with raised plasma-LBP (OR 1.2 [1.04–1.37]) and sTNF-R55 in sputum (OR 1.01 [1.001–1.01]), while HS expressed significantly lowered plasma-LBP (OR 0.8 [0.72–0.95]). Asthma was characterized by higher sputum eosinophilic counts (OR 1.3 [1.05–1.54]), while CB showed a significantly higher proportion of sputum lymphocytic counts (OR 1.5 [1.12–1.9]). Sputum eosinophilia was significantly associated with reversibility after adjusting for smoking, lung function, age, gender and allergy.

Conclusion

Patterns of inflammatory markers in a panel of blood plasma and sputum cells and mediators were discernable in clinical diagnosis groups of respiratory disease. COPD and so-called healthy smokers showed consistent opposite associations with plasma LBP, while chronic bronchitics showed relatively predominant lymphocytic inflammation compared to other diagnosis groups. Only sputum eosinophilia remained significantly associated with reversibility across the spectrum of respiratory disease in smokers with airway complaints.  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