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   76篇
  免费   13篇
  2021年   1篇
  2019年   2篇
  2018年   1篇
  2017年   2篇
  2016年   1篇
  2015年   3篇
  2014年   2篇
  2013年   1篇
  2012年   5篇
  2011年   1篇
  2010年   3篇
  2009年   5篇
  2008年   4篇
  2007年   2篇
  2006年   4篇
  2005年   3篇
  2004年   5篇
  2003年   5篇
  2002年   7篇
  2001年   4篇
  2000年   4篇
  1999年   4篇
  1998年   1篇
  1997年   3篇
  1995年   2篇
  1992年   2篇
  1991年   4篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1981年   1篇
  1980年   1篇
  1977年   1篇
  1971年   1篇
排序方式: 共有89条查询结果,搜索用时 31 毫秒
41.
Abstract  Two new species of Nysius Dallas, N. orarius sp. n. and N. tasmaniensis sp. n. are described from New South Wales and Tasmania (Australia), respectively. A new monotypic genus, Reticulatonysius , with type-species R. queenslandensis sp. n. is described from Queensland, and its systematic relationship with other orsilline genera is discussed.  相似文献   
42.
Tumour infiltrating lymphocytes (TIL) were isolated and expanded from biopsy samples of 4 patients with metastatic melanoma. The patients were treated with autologous expanded TIL and continuous or bolus infusion of Interleukin 2 (IL-2) at a dose of 18 × 106 International Units/m2/day for 5 days starting 36–48 hours after administration of cyclophosphamide at a dose of 1 g/m2. The number of TIL infused ranged from 1010 to 5,56 × 1010 cells. Two patients had stable disease (SD) lasting for 2 1/2 and 4 months respectively and they died 24 and 13 months after therapy. One patient died during therapy due to a pseudomonas septicaemia and another patient developed progressive disease (PD). He died 3 months after the start of therapy. The side effects were substantial but most of them were reversible upon cessation of the treatment.The majority of the expanded TIL of all patients were of the CD8+ phenotype. Cutaneous metastases from two patients, removed after treatment with IL-2 and TIL, showed moderate lymphocytic infiltration also mainly of CD8+ T cells.The treatment with IL-2 and TIL is feasible, but further investigations should continue in an attempt to improve the efficacy of the therapy, to reduce toxicity and to diminish the costs and labour of the culture methods.  相似文献   
43.

Background  

Comparative sequence analysis of complex loci such as resistance gene analog clusters allows estimating the degree of sequence conservation and mechanisms of divergence at the intraspecies level. In banana (Musa sp.), two diploid wild species Musa acuminata (A genome) and Musa balbisiana (B genome) contribute to the polyploid genome of many cultivars. The M. balbisiana species is associated with vigour and tolerance to pests and disease and little is known on the genome structure and haplotype diversity within this species. Here, we compare two genomic sequences of 253 and 223 kb corresponding to two haplotypes of the RGA08 resistance gene analog locus in M. balbisiana "Pisang Klutuk Wulung" (PKW).  相似文献   
44.
Cell fusion, a process that merges two or more cells into one, is required for normal development and has been explored as a tool for stem cell therapy. It has also been proposed that cell fusion causes cancer and contributes to its progression. These functions rely on a poorly understood ability of cell fusion to create new cell types. We suggest that this ability can be understood by considering cells as attractor networks whose basic property is to adopt a set of distinct, stable, self-maintaining states called attractors. According to this view, fusion of two cell types is a collision of two networks that have adopted distinct attractors. To learn how these networks reach a consensus, we model cell fusion computationally. To do so, we simulate patterns of gene activities using a formalism developed to simulate patterns of memory in neural networks. We find that the hybrid networks can assume attractors that are unrelated to parental attractors, implying that cell fusion can create new cell types by nearly instantaneously moving cells between attractors. We also show that hybrid networks are prone to assume spurious attractors, which are emergent and sporadic network states. This finding means that cell fusion can produce abnormal cell types, including cancerous types, by placing cells into normally inaccessible spurious states. Finally, we suggest that the problem of colliding networks has general significance in many processes represented by attractor networks, including biological, social, and political phenomena.  相似文献   
45.
Case study     
  相似文献   
46.
The presence of Ca2+-activated Cl currents (ICl(Ca)) in vascular smooth muscle cells (VSMCs) is well established. ICl(Ca) are supposedly important for arterial contraction by linking changes in [Ca2+]i and membrane depolarization. Bestrophins and some members of the TMEM16 protein family were recently associated with ICl(Ca). Two distinct ICl(Ca) are characterized in VSMCs; the cGMP-dependent ICl(Ca) dependent upon bestrophin expression and the ‘classical’ Ca2+-activated Cl current, which is bestrophin-independent. Interestingly, TMEM16A is essential for both the cGMP-dependent and the classical ICl(Ca). Furthermore, TMEM16A has a role in arterial contraction while bestrophins do not. TMEM16A’s role in the contractile response cannot be explained however only by a simple suppression of the depolarization by Cl channels. It is suggested that TMEM16A expression modulates voltage-gated Ca2+ influx in a voltage-independent manner and recent studies also demonstrate a complex role of TMEM16A in modulating other membrane proteins.  相似文献   
47.
Cancers of the upper aerodigestive tract (UADT) are common forms of malignancy associated with tobacco and alcohol exposures, although human papillomavirus and nutritional deficiency are also important risk factors. While somatically acquired DNA methylation changes have been associated with UADT cancers, what triggers these events and precise epigenetic targets are poorly understood. In this study, we applied quantitative profiling of DNA methylation states in a panel of cancer-associated genes to a case-control study of UADT cancers. Our analyses revealed a high frequency of aberrant hypermethylation of several genes, including MYOD1, CHRNA3 and MTHFR in UADT tumors, whereas CDKN2A was moderately hypermethylated. Among differentially methylated genes, we identified a new gene (the nicotinic acetycholine receptor gene) as target of aberrant hypermethylation in UADT cancers, suggesting that epigenetic deregulation of nicotinic acetycholine receptors in non-neuronal tissues may promote the development of UADT cancers. Importantly, we found that sex and age is strongly associated with the methylation states, whereas tobacco smoking and alcohol intake may also influence the methylation levels in specific genes. This study identifies aberrant DNA methylation patterns in UADT cancers and suggests a potential mechanism by which environmental factors may deregulate key cellular genes involved in tumor suppression and contribute to UADT cancers.Key words: DNA methylation, upper aerodigestive tract, cancer, risk factors, biomarkers  相似文献   
48.
Prostacyclin infused intravenously in human volunteers induces ex vivo inhibition of platelet aggregation, tachycardia and hypotension. The inhibition of platelet aggregation is obtained with slightly lower doses than those which exhibit cardiovascular effects.The cardiovascular effects disappeared within a few minutes after discontinuing the infusion of prostacyclin but the platelet effects were longer lasting.Prostacyclin did not have any effect on platelet count, platelet factor 3, accelerated partial thromboplastin time, prothrombin time, euglobulin clot lysis time, fibrinogen degradation products, blood glucose concentration or urine sodium potassium ratio.  相似文献   
49.
50.
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