全文获取类型
收费全文 | 27325篇 |
免费 | 2724篇 |
国内免费 | 2241篇 |
专业分类
电工技术 | 1489篇 |
技术理论 | 1篇 |
综合类 | 2242篇 |
化学工业 | 2100篇 |
金属工艺 | 370篇 |
机械仪表 | 837篇 |
建筑科学 | 628篇 |
矿业工程 | 204篇 |
能源动力 | 593篇 |
轻工业 | 209篇 |
水利工程 | 223篇 |
石油天然气 | 202篇 |
武器工业 | 108篇 |
无线电 | 5839篇 |
一般工业技术 | 1643篇 |
冶金工业 | 391篇 |
原子能技术 | 58篇 |
自动化技术 | 15153篇 |
出版年
2024年 | 119篇 |
2023年 | 471篇 |
2022年 | 597篇 |
2021年 | 669篇 |
2020年 | 792篇 |
2019年 | 710篇 |
2018年 | 646篇 |
2017年 | 863篇 |
2016年 | 1015篇 |
2015年 | 1146篇 |
2014年 | 1598篇 |
2013年 | 1834篇 |
2012年 | 1740篇 |
2011年 | 2076篇 |
2010年 | 1578篇 |
2009年 | 1938篇 |
2008年 | 2050篇 |
2007年 | 1945篇 |
2006年 | 1552篇 |
2005年 | 1353篇 |
2004年 | 1152篇 |
2003年 | 995篇 |
2002年 | 892篇 |
2001年 | 762篇 |
2000年 | 706篇 |
1999年 | 584篇 |
1998年 | 501篇 |
1997年 | 432篇 |
1996年 | 358篇 |
1995年 | 281篇 |
1994年 | 213篇 |
1993年 | 178篇 |
1992年 | 126篇 |
1991年 | 76篇 |
1990年 | 53篇 |
1989年 | 39篇 |
1988年 | 32篇 |
1987年 | 24篇 |
1986年 | 17篇 |
1985年 | 46篇 |
1984年 | 37篇 |
1983年 | 36篇 |
1982年 | 40篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
On‐Line Detection Of State‐Of‐Charge In Lead Acid Battery Using Radial Basis Function Neural Network
To realize a stable supply of electric power in an automobile, an accurate and reliable detection method of SOC (state‐of‐charge) in a lead acid battery is required. However the dynamics of the battery is very complicated. The characteristics of the battery greatly change due to its degradation. Moreover a automobile has many driving patterns, which are unknown beforehand. Thus it is not easy to detect the SOC analytically. In this paper, to overcome this problem, a new on‐line SOC detection method with a radial basis function neural network is proposed. In order to increase the detection accuracy of degraded batteries, physical values related to the degradation degree are used as input signal in the neural network. The detection accuracies for different sized batteries and various degradation states are investigated. 相似文献
132.
133.
Tree-shaped flow structures designed by minimizing path lengths 总被引:1,自引:0,他引:1
S. LorenteW. Wechsatol A. Bejan 《International Journal of Heat and Mass Transfer》2002,45(16):3299-3312
This paper outlines a direct route to the construction of effective tree-shaped flow structures. Dendritic flow structures dominate the design of natural and engineered flow systems, especially in thermal and fluid systems. The starting point is the optimization of the shape of each elemental area or volume, such that the length of the flow path housed by the element is minimized. Proceeding toward larger and more complex structures - from elements, to first constructs, second constructs, etc. - the paper develops tree-shaped flow structures between one point and a straight line, one point and a plane, a circle and its center, and a point and many points distributed uniformly over an area. In the latter, the construction method is applied to a fluid flow configuration with laminar fully developed flow. The constructions reveal several features that are supported by empirical observations of natural tree-shaped flows: asymmetry, flow rate imbalance, pairing or bifurcation, angles between branches, and Y-shaped constructs that lie in a plane. It is shown that these basic features are necessary because of “packing”, i.e., assembling optimized elements into a fixed space, and filling the space completely. For the flow between an area and one point, the best elemental shape is the regular hexagon. It is shown that the emergence of string-shaped links that connect two or more elements are necessary features, which are also required by packing. Strings cover some of the inner zones of the tree network, particularly the inner zones of large and complex trees. Dichotomous Y-shaped constructs dominate the tree structure, especially the peripheral zones of the tree canopy. The practical importance of the simplified design method is discussed. 相似文献
134.
手势语言识别的神经网络方法 总被引:1,自引:1,他引:0
提供了一种用于人机交互(HCI)的手势语言可视化识别方法。该方法包括用于几种控制命令的手势的探测、分割、特征提取及识别,第一步的处理都用到了神经网络方法,像肤色探测、主元分析(PCA)以及在编码识别。实验结果显示正确识别率高达94%。 相似文献
135.
136.
137.
何明一 《电子科学学刊(英文版)》1994,11(1):1-10
A new concept, the generalized inverse group (GIG) of signal, is firstly proposed and its properties, leaking coefficients and implementation with neural networks are presented. Theoretical analysis and computational simulation have shown that (1) there is a group of finite length of generalized inverse signals for any given finite signal, which forms the GIG; (2) each inverse group has different leaking coefficients, thus different abnormal states; (3) each GIG can be implemented by a grouped and improved single-layer perceptron which appears with fast convergence. When used in deconvolution, the proposed GIG can form a new parallel finite length of filtering deconvolution method. On off-line processing, the computational time is reduced to O(N) from O(N2). And the less the leaking coefficient is, the more reliable the deconvolution will be. 相似文献
138.
139.
Energy minimization and design for testability 总被引:6,自引:0,他引:6
Srimat T. Chakradhar Vishwani D. Agrawal Michael L. Bushnell 《Journal of Electronic Testing》1994,5(1):57-66
The problem of fault detection in general combinational circuits is NP-complete. The only previous result on identifying easily testable circuits is due to Fujiwara who gave a polynomial time algorithm for detecting any single stuck fault inK-bounded circuits. Such circuits may only contain logic blocks with no more thanK input lines and the blocks are so connected that there is no reconvergent fanout among them. We introduce a new class of combinational circuits called the (k, K)-circuits and present a polynomial time algorithm to detect any single or multiple stuck fault in such circuits. We represent the circuit as an undirected graphG with a vertex for each gate and an edge between a pair of vertices whenever the corresponding gates have a connection. For a (k, K)-circuit,G is a subgraph of ak-tree, which, by definition, cannot have a clique of size greater thank+1. Basically, this is a restriction on gate interconnections rather than on the function of gates comprising the circuit. The (k, K)-circuits are a generalization of Fujiwara'sK-bounded circuits. Using the bidirectional neural network model of the circuit and the energy function minimization formulation of the fault detection problem, we present a test generation algorithm for single and multiple faults in (k, K)-circuits. This polynomial time aggorithm minimizes the energy function by recursively eliminating the variables. 相似文献
140.