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   36篇
  免费   0篇
现状及发展   10篇
研究方法   1篇
综合类   25篇
  2013年   1篇
  2012年   2篇
  2011年   2篇
  2008年   1篇
  2007年   1篇
  2005年   8篇
  2002年   1篇
  2001年   1篇
  1998年   5篇
  1989年   1篇
  1985年   3篇
  1972年   2篇
  1970年   1篇
  1969年   3篇
  1968年   2篇
  1946年   2篇
排序方式: 共有36条查询结果,搜索用时 0 毫秒
31.
神经网络在CB油田储层预测和储层厚度计算中的应用   总被引:1,自引:0,他引:1  
根据CB油田的特点提出了利用神经网络进行储层预测和计算地层厚度的方法。将传统的储层预测方法与人工神经网络相结合,能较好地解决CB油田的储层预测问题。利用神经网络的非线性映射特点实现了地震特征与地层厚度之间的映射,从而可以准确地求取地层厚度。用该方法设计了2口探井,实际钻井结果表明,这种方法的预测结果准确、可靠。  相似文献   
32.
Recent advances in whole-genome sequencing have brought the vision of personal genomics and genomic medicine closer to reality. However, current methods lack clinical accuracy and the ability to describe the context (haplotypes) in which genome variants co-occur in a cost-effective manner. Here we describe a low-cost DNA sequencing and haplotyping process, long fragment read (LFR) technology, which is similar to sequencing long single DNA molecules without cloning or separation of metaphase chromosomes. In this study, ten LFR libraries were made using only ~100?picograms of human DNA per sample. Up to 97% of the heterozygous single nucleotide variants were assembled into long haplotype contigs. Removal of false positive single nucleotide variants not phased by multiple LFR haplotypes resulted in a final genome error rate of 1 in 10?megabases. Cost-effective and accurate genome sequencing and haplotyping from 10-20 human cells, as demonstrated here, will enable comprehensive genetic studies and diverse clinical applications.  相似文献   
33.
MicroRNA expression profiles classify human cancers   总被引:13,自引:0,他引:13  
Recent work has revealed the existence of a class of small non-coding RNA species, known as microRNAs (miRNAs), which have critical functions across various biological processes. Here we use a new, bead-based flow cytometric miRNA expression profiling method to present a systematic expression analysis of 217 mammalian miRNAs from 334 samples, including multiple human cancers. The miRNA profiles are surprisingly informative, reflecting the developmental lineage and differentiation state of the tumours. We observe a general downregulation of miRNAs in tumours compared with normal tissues. Furthermore, we were able to successfully classify poorly differentiated tumours using miRNA expression profiles, whereas messenger RNA profiles were highly inaccurate when applied to the same samples. These findings highlight the potential of miRNA profiling in cancer diagnosis.  相似文献   
34.
Zusammenfassung Untersuchungen anVicia faba- undHordeum-Wurzelspitzen sowie anSorghum-Pollenmutterzellen ergeben keine Hinweise für eine zytogenetische Wirksamkeit des Triazin-Herbizides Atrazin in Pflanzen.

The authors are greatly indebted to Dr.U. Leuthold for his help in conducting the experiments. The excellent technical assistance of Mrs.J. Determeyer and MissD. Kempf is gratefully acknowledged.  相似文献   
35.
Summary The triazine herbicides are potent inhibitors of theHill reaction, resembling the phenylureas, acylanilides and carbamates. The inhibition of the photosynthesis by the triazines is the most obvious explanation for their mode of action in plant metabolism. Besides this there are also effects on light independent reactions where the effective concentrations are higher than those inhibiting the photosynthesis. Particularly, a positive influence of the triazines on the uptake of the nutrients by the roots was noted. Changes in the nitrogen metabolism of the plants, due to increased uptake of nitrate from the medium, result in a higher content of organic nitrogen in the plants.Several enzyme systems in plants and in micro-organisms are influenced by the triazine herbicides. Until now, the mechanism of action has not been elucidated.Concerning the phenomenon of the selectivity of the triazine herbicides, several factors may be responsible. The different abilities of the plant species to metabolize the herbicide and to translocate it to the active centres in the cells are significant from the biochemical point of view.

Une partie de ce travail a été présentée lors de la 463e séance de la Biochemical Society, Aberystwyth, septembre 1966.P. W. Müller, Biochem. J.101, 1P. (1966).Nous tenons à exprimer nos remerciements àR. Truan qui a bien voulu se charger de la version française ainsi qu'àG. Dupuis pour sa participation à la mise au point du manuscrit.  相似文献   
36.
临清坳陷莘县凹陷油气勘探远景评价   总被引:1,自引:0,他引:1  
对莘县凹陷的构造、沉积、盆地模拟及油气勘探远景等进行了深入研究。结果表明,该凹陷具有浅、中、深3个勘探层次,浅层馆陶组和沙一段以储集次生油及低成熟油气为主;中层沙二段、沙三段以自生自储型油藏为主;深层孔二段以储集高成熟油气、石炭-二迭系以煤成气为主。此地区有着极广阔的勘探远景。  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