全文获取类型
收费全文 | 3033篇 |
免费 | 127篇 |
国内免费 | 135篇 |
专业分类
电工技术 | 50篇 |
综合类 | 55篇 |
化学工业 | 204篇 |
金属工艺 | 98篇 |
机械仪表 | 226篇 |
建筑科学 | 83篇 |
矿业工程 | 22篇 |
能源动力 | 153篇 |
轻工业 | 89篇 |
水利工程 | 6篇 |
石油天然气 | 27篇 |
武器工业 | 5篇 |
无线电 | 503篇 |
一般工业技术 | 428篇 |
冶金工业 | 46篇 |
原子能技术 | 54篇 |
自动化技术 | 1246篇 |
出版年
2024年 | 4篇 |
2023年 | 34篇 |
2022年 | 38篇 |
2021年 | 51篇 |
2020年 | 45篇 |
2019年 | 45篇 |
2018年 | 70篇 |
2017年 | 88篇 |
2016年 | 77篇 |
2015年 | 87篇 |
2014年 | 148篇 |
2013年 | 179篇 |
2012年 | 153篇 |
2011年 | 248篇 |
2010年 | 165篇 |
2009年 | 229篇 |
2008年 | 197篇 |
2007年 | 186篇 |
2006年 | 181篇 |
2005年 | 138篇 |
2004年 | 118篇 |
2003年 | 102篇 |
2002年 | 91篇 |
2001年 | 72篇 |
2000年 | 66篇 |
1999年 | 50篇 |
1998年 | 63篇 |
1997年 | 64篇 |
1996年 | 52篇 |
1995年 | 43篇 |
1994年 | 42篇 |
1993年 | 34篇 |
1992年 | 24篇 |
1991年 | 14篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1973年 | 1篇 |
排序方式: 共有3295条查询结果,搜索用时 15 毫秒
71.
提出一种具有暂态混沌的细胞神经网络,该网络是利用欧拉算法将模型的状态方程转化为离散形式并引入一项负的自反馈而形成的.由对单个神经元的仿真发现,该模型具有分叉和混沌的特性.在函数优化中,该网络首先经过一个倍周期倒分叉过程进行混沌搜索;然后进行类似Hopfield网络的梯度搜索.由于该网络利用了混沌搜索固有的随机性和轨道遍历性,因而具有较强的全局寻优的能力.最后通过2个函数优化的例子验证了该网络的有效性. 相似文献
72.
针对移动机器人全局最优路径规划问题,提出一种基于细胞自动机的路径规划算法.该算法首先将移动机器人的起点、目标点和空间障碍物定义为一组离散的细胞状态,建立环境的细胞自动机模型;然后由机器人移动的曼哈顿距离设计演化规则;最后根据演化后的细胞状态搜索最优路径.对简单和复杂环境下的机器人路径规划问题进行了仿真实验,实验结果验证了该算法的有效性. 相似文献
73.
74.
A new method for robust fixed-order H∞ controller design by convex optimization for multivariable systems is investigated. Linear Time-Invariant Multi-Input Multi-Output (LTI-MIMO) systems represented by a set of complex values in the frequency domain are considered. It is shown that the Generalized Nyquist Stability criterion can be approximated by a set of convex constraints with respect to the parameters of a multivariable linearly parameterized controller in the Nyquist diagram. The diagonal elements of the controller are tuned to satisfy the desired performances, while simultaneously, the off-diagonal elements are designed to decouple the system. Multimodel uncertainty can be directly considered in the proposed approach by increasing the number of constraints. The simulation examples illustrate the effectiveness of the proposed approach. 相似文献
75.
I.G. GeorgoudasG.Ch. Sirakoulis E.M. ScordilisI. Andreadis 《Advances in Engineering Software》2011,42(9):623-633
A two-dimensional (2-D) cellular automata (CA) dynamic system constituted of cells-charges has been proposed for the simulation of the earthquake process. In this paper, the study is focused on the optimal parameterisation of the model introducing the use of genetic algorithm (GA). The optimisation of the CA model parameterisation, by applying a standard GA, extends its ability to study various hypotheses concerning the seismicity of the region under consideration. The GA evolves an initially random population of candidate solutions of model parameters, such that in time appropriate solutions to emerge. The quality criterion is realised by taking into account the extent that the simulation results match the Gutenberg-Richter (GR) law derived from recorded data of the area under test. The simulation results presented here regard regions of Greece with different seismic and geophysical characteristics. The results found are in good quantitative and qualitative agreement with the GR scaling relations. 相似文献
76.
77.
78.
S. BaumgartenAuthor VitaeR. RobelekAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(2):798-804
Cells regulate their volume in response to changes in osmolarity of both, their extracellular and intracellular environments. As stability of the cell volume is a compelling exigency for cellular integrity, techniques for a sensitive, time-resolved volume measurement of adherently grown mammalian cells attract considerable interest, especially in the field of cell physiology and biology. In this study we apply a surface plasmon resonance (SPR) based biosensor for the comparative analysis of the volume responses of two renal epithelial cell types to non-isotonic challenges. The on-line, label-free and non-invasive biosensor format shows distinct similarities and differences in the reaction kinetics of the two cell types. Furthermore regulatory volume responses to the osmotic stimuli as well as their inhibition by Gd3+ ions can be observed with a high time-resolution. Limit-of-detection measurements indicate the high sensitivity of the sensor capable of detecting cellular volume responses of adherently grown mammalian cells to osmotic stimuli well below a bioanalytical relevant value of 5 mOsm/kg. 相似文献
79.
Tommaso Bolognesi 《Information Processing Letters》2009,109(13):668-674
Based on the mobile automaton model, an algorithm is introduced that grows planar, tri-valent graphs by exhibiting a peculiar, twofold dynamics. In a first phase, graph growth appears to be pseudo-random and O(n) then it settles to a very regular behavior and rate. A pseudo-random mobile automaton is already known; the new automaton provides now a finite, but surprisingly long, pseudo-random, linear growth process. Applications of mobile automata to fundamental physics and quantum gravity have been recently suggested. 相似文献
80.
Duccio Rocchini 《Remote sensing of environment》2009,113(5):904-906
Remote sensing is a powerful tool for characterizing, estimating or modelling species diversity. Differences in environmental properties of different habitats should lead to differences of spectral responses, which can be detected by satellite imagery. Hence, spectral distance may be related to species diversity. Based on previous studies, Krishnaswamy et al. [Krishnaswamy, J., Bawa, K. S., Ganeshaiah, K. N., & Kiran, M. C. (2009). Quantifying and mapping biodiversity and ecosystem services: Utility of a multi-season NDVI based Mahalanobis distance surrogate. Remote Sensing of Environment.] used spectral distance to estimate species diversity. Since a noisy scatterplot of species versus spectral diversity is expected, the commonly used Ordinary Least Square regression may fail to detect trends which occur across other quantiles than the mean.Krishnaswamy et al. [Krishnaswamy, J., Bawa, K. S., Ganeshaiah, K. N., & Kiran, M. C. (2009). Quantifying and mapping biodiversity and ecosystem services: Utility of a multi-season NDVI based Mahalanobis distance surrogate. Remote Sensing of Environment.] proposed a quantile-quantile plot method as an alternative to conventional regression based approaches which are inappropriate for dependent pair-wise dissimilarity or similarity data. By this commentary I demonstrate the utility of a quantile regression technique to complement the Krishnaswamy et al. [Krishnaswamy, J., Bawa, K. S., Ganeshaiah, K. N., & Kiran, M. C. (2009). Quantifying and mapping biodiversity and ecosystem services: Utility of a multi-season NDVI based Mahalanobis distance surrogate. Remote Sensing of Environment.] graphical approach in terms of a predictive model. 相似文献