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   103篇
  免费   4篇
  国内免费   1篇
化学工业   16篇
金属工艺   4篇
建筑科学   9篇
能源动力   4篇
轻工业   11篇
水利工程   2篇
石油天然气   3篇
无线电   6篇
一般工业技术   19篇
冶金工业   11篇
自动化技术   23篇
  2023年   2篇
  2022年   4篇
  2021年   7篇
  2020年   1篇
  2019年   7篇
  2018年   7篇
  2017年   7篇
  2016年   4篇
  2015年   1篇
  2014年   5篇
  2013年   4篇
  2012年   4篇
  2011年   5篇
  2010年   5篇
  2009年   2篇
  2008年   2篇
  2007年   2篇
  2006年   1篇
  2005年   3篇
  2004年   2篇
  2003年   8篇
  2002年   2篇
  2000年   1篇
  1999年   2篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1992年   1篇
  1990年   1篇
  1986年   1篇
  1982年   1篇
  1981年   1篇
  1979年   2篇
  1978年   2篇
  1977年   2篇
  1976年   1篇
排序方式: 共有108条查询结果,搜索用时 15 毫秒
21.
22.
The title problem is equivalent to a torsional mixed boundary value problem in the theory of elasticity in which the only non-zero displacement component is specified inside the circular area r ? l and the shearing stress σθz, is zero in the area r > 1 on the face z = 0; the continuity of the displacement and the shearing stress σθz is assumed at the interface z = h between the layer and the half-space having different modulii of rigidity. The modulii of rigidity are assumed to be continuous functions of 2. The problem is reduced to the solution of a Fredholm integral equation of the second kind whose iterative solution has been obtained valid for values of h >l, for a few particular cases. Expression for the torque T required to rotate the die through an angle ω has been obtained for the general as well as particular cases.  相似文献   
23.
The study of single-interface transformations under controlled conditions offers insights into the similarities and distinctions between solidification and solid-solid transformations. In this contribution, we consider some parallels between the formation of a layer of ferrite on an originally austenitic steel bar and the growth of the columnar zone in the solidification of an alloy ingot. The necessary conditions for solid-solid interfacial breakdown of a decarburization front are explored and the evidence to date reviewed. The response of some Fe-C-Mn-Si steels to controlled decarburization is considered, and we present a first report of the morphological instability of a ferrite/austenite decarburization interface, and compare it with the interfacial breakdown in the solid-liquid interface. The instability is tentatively ascribed to the effects of grain-boundary nucleation and/or grain-boundary diffusion of alloying elements in austenite. Other similarities (and differences) between the growth of a ferrite layer on an alloy steel and the development of the columnar zone of an ingot are discussed.  相似文献   
24.
Aurora kinase B (AKB) is a crucial signaling kinase with an important role in cell division. Therefore, inhibition of AKB is an attractive approach to the treatment of cancer. In the present work, extensive quantitative structure–activity relationships (QSAR) analysis has been performed using a set of 561 structurally diverse aurora kinase B inhibitors. The Organization for Economic Cooperation and Development (OECD) guidelines were used to develop a QSAR model that has high statistical performance (R2tr = 0.815, Q2LMO = 0.808, R2ex = 0.814, CCCex = 0.899). The seven-variable-based newly developed QSAR model has an excellent balance of external predictive ability (Predictive QSAR) and mechanistic interpretation (Mechanistic QSAR). The QSAR analysis successfully identifies not only the visible pharmacophoric features but also the hidden features. The analysis indicates that the lipophilic and polar groups—especially the H-bond capable groups—must be present at a specific distance from each other. Moreover, the ring nitrogen and ring carbon atoms play important roles in determining the inhibitory activity for AKB. The analysis effectively captures reported as well as unreported pharmacophoric features. The results of the present analysis are also supported by the reported crystal structures of inhibitors bound to AKB.  相似文献   
25.
The preparation of carboxymethyl (CM)–Cassia tora gum (CTG) with monochloroacetic acid and sodium hydroxide was investigated under different reaction conditions. The carboxymethylation reaction was studied with respect to the degree of substitution of CM–CTG. The variables studied were the concentration of reactants, methanol–water ratio (solvent), reaction time, and reaction temperature. Carboxymethylation of CTG increased its solubility in cold water and the stability of its paste to microorganisms. Regardless of the degree of substitution of these products, their aqueous solutions were characterized by non‐Newtonian pseudoplastic behavior. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3216–3219, 2003  相似文献   
26.
This paper presents a novel method for global anomaly detection in crowded scenes. The optical flow of frames is used to extract the foreground of areas with people motions in the crowd in the form of layers. The optical flow between two frames generates one layer. The proposed method applies the metaheuristic of artificial bacteria colony as a robust algorithm to optimize the extracted layers. Artificial bacteria cover all regions of interest that have high movement between frames. The artificial bacteria colony adapts quickly to the most varied scenarios. Moreover, the algorithm has low sensibility to noise and to sudden changes in video lighting as captured by optical flow. The bacteria population of the colonies, its food storage and the colony’s centroid position regarding each optical flow layer, are used as input to train a Kohonen’s neural network. Once trained the network is able to detect specific events based on behavior patterns similarity, as produced by the bacteria colony during such events. Experiments are conducted on available public dataset. The achieved results show that the proposed method captures the dynamics of the crowd behavior successfully, revealing that the proposed scheme outperforms the available state-of-the-art algorithms for global anomaly detection.  相似文献   
27.
How to comprehensively explore, improve and deploy multimedia social networks (MSNs) has become a hot topic in the era of emerging pervasive mobile multimedia. More and more MSNs offer a great number of convenient tools, services, and applications for multimedia contents including video and audio that users share willingly and on demand. However, concerns with digital rights management (DRM)-oriented multimedia security, as well as the efficiency of multimedia usage and sharing are meanwhile intensified due to easier distribution and reproduction of multimedia content in a wide range of social networks. The paper proposes a comprehensive framework for multimedia social network, and realized a cross-platform MSN prototype system, named as CyVOD, to support two kinds of DRM modes. The proposed framework effectively protects copyrighted multimedia contents against piracy, and supports a more efficient recommendation system for its better handling of the tradeoff between multimedia security and ease of use.  相似文献   
28.
The imaging, pointing, and tracking performance of precision optical systems are degraded by various disturbances which induce optical beam jitter. The present research proposes adaptive filter control methods for actively attenuating beam jitter using a fast steering mirror. Control loops with various structures of adaptive transversal filters are developed to suppress time-varying or uncertain jitter, and their characteristics and performances are compared. In particular, for situations when obtaining reference signals which are fully coherent with the disturbance is not possible, methods for incorporating multiple semi-coherent reference signals into the control law are developed. An index variable is defined to measure quality of various references signals, and a few signals are selected based on this index. The developed controllers are verified on a jitter control testbed, and experimental results show that the adaptive methods show superior performance in jitter attenuation over the conventional non-adaptive method.  相似文献   
29.
30.

The Needleman-Wunsch (NW) is a dynamic programming algorithm used in the pairwise global alignment of two biological sequences. In this paper, three sets of parallel implementations of the NW algorithm are presented using a mixture of specialized software and hardware solutions: POSIX Threads-based, SIMD Extensions-based and a GPU-based implementations. The three implementations aim at improving the performance of the NW algorithm on large scale input without affecting its accuracy. Our experiments show that the GPU-based implementation is the best implementation as it achieves performance 72.5X faster than the sequential implementation, whereas the best performance achieved by the POSIX threads and the SIMD techniques are 2X and 18.2X faster than the sequential implementation, respectively.

  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