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   86篇
  免费   2篇
  国内免费   2篇
系统科学   1篇
理论与方法论   1篇
现状及发展   24篇
研究方法   16篇
综合类   48篇
  2020年   1篇
  2018年   2篇
  2015年   1篇
  2014年   2篇
  2012年   6篇
  2011年   12篇
  2009年   4篇
  2008年   4篇
  2007年   4篇
  2006年   3篇
  2005年   4篇
  2004年   5篇
  2003年   2篇
  2002年   3篇
  2001年   6篇
  2000年   1篇
  1999年   3篇
  1995年   2篇
  1994年   3篇
  1987年   1篇
  1985年   2篇
  1981年   2篇
  1979年   4篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1973年   2篇
  1967年   1篇
  1965年   1篇
  1958年   1篇
  1955年   1篇
  1954年   1篇
  1948年   1篇
排序方式: 共有90条查询结果,搜索用时 15 毫秒
41.
Summary A simple, low cost interspike interval analyzer for the analysis of trains of nerve impulses is described. The analyzer is built with readily available integrated circuits and has been used to analyze spike trains in the lateral vestibular nucleus of cats.Acknowledgment. This research is supported in part by Higher Degrees and Research Grant No. 158/363 to J.C.H. from the University of Hong Kong.  相似文献   
42.
The term neurodevelopmental disorder broadly encompasses conditions thought to arise early in development and includes schizophrenia, bipolar disorder and autism among others. These conditions share a number of genetic and environmental risk factors postulated to lead to common difficulties in socio-emotional processing, communication and cognitive function. The alternative position is that, while the same traits are affected across these conditions, the nature or direction in which they are modified may be distinct. MRI studies provide a rapidly expanding and rich database which we propose can be used to contribute to this debate. Anatomical likelihood estimation (ALE) is a method of meta-analysis applied to voxel-based MRI studies. We have adapted this method to explore the extent to which schizophrenia and bipolar disorder and schizophrenia and autism share a common brain structural phenotype. We will review this work here and discuss whether there is sufficient other evidence to justify a common framework for further research into the inter-relatedness of such conditions.  相似文献   
43.
本书详细介绍了数字信号处理器的硬件合成和硬件定制实现的优化方法领域的研究动态,高层次的讨论了在满足用户给定的限制条件下,如何自动化进行高性能一面积比(area—efficient)设计的技术,指出了这类技术可以用于线性系统和非线性系统:包括有限长脉冲(FIR)和无限长脉冲(IIR)滤波器、离散余弦变换(DCT)、多相滤波器组和自适应最小均方(LMS)滤波器。  相似文献   
44.
Mechanical deflection of the sensory hair bundles of receptor cells in the inner ear causes ion channels located at the tips of the bundle to open, thereby initiating the perception of sound. Although some protein constituents of the transduction apparatus are known, the mechanically gated transduction channels have not been identified in higher vertebrates. Here, we investigate TRP (transient receptor potential) ion channels as candidates and find one, TRPA1 (also known as ANKTM1), that meets criteria for the transduction channel. The appearance of TRPA1 messenger RNA expression in hair cell epithelia coincides developmentally with the onset of mechanosensitivity. Antibodies to TRPA1 label hair bundles, especially at their tips, and tip labelling disappears when the transduction apparatus is chemically disrupted. Inhibition of TRPA1 protein expression in zebrafish and mouse inner ears inhibits receptor cell function, as assessed with electrical recording and with accumulation of a channel-permeant fluorescent dye. TRPA1 is probably a component of the transduction channel itself.  相似文献   
45.
Cheung F 《Nature》2011,480(7378):S82-S83
  相似文献   
46.
Moving vehicle loads, associated with roadway traffic can induce significant dynamic effects on the structural behaviours of bridges, especially for long-span bridges. The main objective of current research is to study traffic induced dynamic responses of long-span box-girder bridges. The finite element method has been employed in this study to obtain a three-dimensional mathematical model for the bridge system. For vehicle-bridge dynamic interaction analysis, the vehicle is modeled as a more realistic three-axle, six-wheel system, and the corresponding dynamic interaction equations have been derived. The bridge-vehicle interaction is affected by many factors. The current study has been focused on such factors as: vehicle speed, vehicle damping ratio, multiple traffic lanes, mass ratio of vehicle and bridge, and dynamic characteristics of bridge. Case studies have been conducted to investigate these factors by using several box girder bridge examples including Confederation Bridge, the longest box girder bridge in the world.  相似文献   
47.
The plant reproductive process of pollination involves a series of interactions between the male gametophyte (the pollen grain or pollen tube) and extracellular matrix (ECM) molecules secreted by different cell types along the pollen tube growth pathway in the female organ, the pistil. These interactions are believed to signal and regulate the pollen tube growth process to effect successful delivery of the sperm cells to the ovules where fertilization takes place. Hydroxyproline-rich glycoproteins secreted by plant cells are believed to play a broad range of functions, ranging from providing structural integrity to mediating cell-cell interactions and communication. The pistil and pollen tube ECM is enriched in these highly glycosylated proteins. Our discussions here will focus on a number of these proteins for which most information has been available, from Nicotiana tabacum, its self-incompatible relative N. alata, and Zea mays. In addition, the regulation of the synthesis and glyco-modification of one of these proteins, TTS (transmitting tissue-specific) protein from N. tabacum will be discussed in the light of how differential glycosylation may be used to regulate molecular interactions within the ECM.  相似文献   
48.
客家菜馆的变迁反映出战后香港社会的文化发展和饮食方式的变化 ,它是洞悉传统习俗和社会阶级关系变化时一个重要参数 ,对客家菜馆的研究有助于说明香港社会生活方式的变迁和社会发展  相似文献   
49.
50.
We investigate the effects of additive outliers on the least squares (LS) estimation of threshold autoregressive models. The class of generalized-M (GM) estimates for linear time series is modified and applied to non-linear threshold processes. A Monte Carlo experiment is carried out to study the robust properties of these estimates. Their relative forecasting performances are also examined. The results indicate that the GM method is preferable to the LS estimation when the observations are contaminated by additive outliers. A real example is also given to illustrate the proposed method.  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