全文获取类型
收费全文 | 59212篇 |
免费 | 8142篇 |
国内免费 | 6256篇 |
专业分类
电工技术 | 5385篇 |
技术理论 | 3篇 |
综合类 | 6811篇 |
化学工业 | 3262篇 |
金属工艺 | 1707篇 |
机械仪表 | 3637篇 |
建筑科学 | 2212篇 |
矿业工程 | 1282篇 |
能源动力 | 1560篇 |
轻工业 | 1433篇 |
水利工程 | 1304篇 |
石油天然气 | 1136篇 |
武器工业 | 654篇 |
无线电 | 9504篇 |
一般工业技术 | 3913篇 |
冶金工业 | 1390篇 |
原子能技术 | 201篇 |
自动化技术 | 28216篇 |
出版年
2024年 | 584篇 |
2023年 | 1679篇 |
2022年 | 2589篇 |
2021年 | 2915篇 |
2020年 | 2967篇 |
2019年 | 2221篇 |
2018年 | 1776篇 |
2017年 | 1955篇 |
2016年 | 2009篇 |
2015年 | 2246篇 |
2014年 | 3121篇 |
2013年 | 3492篇 |
2012年 | 3752篇 |
2011年 | 4123篇 |
2010年 | 3258篇 |
2009年 | 3738篇 |
2008年 | 4013篇 |
2007年 | 4323篇 |
2006年 | 3656篇 |
2005年 | 3276篇 |
2004年 | 2746篇 |
2003年 | 2265篇 |
2002年 | 1921篇 |
2001年 | 1713篇 |
2000年 | 1470篇 |
1999年 | 1243篇 |
1998年 | 996篇 |
1997年 | 825篇 |
1996年 | 676篇 |
1995年 | 535篇 |
1994年 | 390篇 |
1993年 | 282篇 |
1992年 | 204篇 |
1991年 | 122篇 |
1990年 | 98篇 |
1989年 | 63篇 |
1988年 | 61篇 |
1987年 | 38篇 |
1986年 | 41篇 |
1985年 | 48篇 |
1984年 | 43篇 |
1983年 | 40篇 |
1982年 | 42篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 4篇 |
1960年 | 3篇 |
1959年 | 5篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
122.
123.
124.
通过对给定样本模式的学习,构建的三层神经网络模型能够获取评价专家的经验、知识、主观判断以及对目标重要性的权重协调能力,较好地保证评价结果的客观性.实例证明,人工神经网络方法应用于组织网络化发展评价是可行和有效的. 相似文献
125.
The emergence of synchronization in a network of coupled oscillators is a fascinating subject of multidisciplinary research. This survey reviews the vast literature on the theory and the applications of complex oscillator networks. We focus on phase oscillator models that are widespread in real-world synchronization phenomena, that generalize the celebrated Kuramoto model, and that feature a rich phenomenology. We review the history and the countless applications of this model throughout science and engineering. We justify the importance of the widespread coupled oscillator model as a locally canonical model and describe some selected applications relevant to control scientists, including vehicle coordination, electric power networks, and clock synchronization. We introduce the reader to several synchronization notions and performance estimates. We propose analysis approaches to phase and frequency synchronization, phase balancing, pattern formation, and partial synchronization. We present the sharpest known results about synchronization in networks of homogeneous and heterogeneous oscillators, with complete or sparse interconnection topologies, and in finite-dimensional and infinite-dimensional settings. We conclude by summarizing the limitations of existing analysis methods and by highlighting some directions for future research. 相似文献
126.
This contribution concerns variance analysis of linear multi-input single-output models when the inputs are temporally white but where different inputs may be correlated. An expression is provided for the variance of a linearly parametrized estimate of the frequency response function from one block, i.e. from one input to the output. In particular, this expression reveals that the variance increases in one block when the number of estimated parameters in another block is increased, but levels off when the number of parameters in the other block reaches the number of parameters in the block in question. It also quantifies exactly how correlation between inputs affects the resulting accuracy and a graphical representation is provided for this purpose. The results are applicable to parallel MISO Hammerstein models when the nonlinearities are known and generalize an existing variance expression for this type of model. 相似文献
127.
In the present paper, we investigate the output-controllability and optimal output control problems of a state-dependent switched Boolean control network. By using the semi-tensor product, the algebraic form of the system is obtained. Then, output-controllability problems of the system are discussed and some necessary and sufficient conditions are given. Next, the Mayer-type optimal output control issue is considered and an algorithm is provided to find out the control sequence. At last, an example is given to show the effectiveness of the main results. 相似文献
128.
The aim of the paper is to design high-order artificial boundary conditions for the Schrödinger equation on unbounded domains in parallel with a treatment of the heat equation. We first introduce a circular artificial boundary to divide the unbounded definition domain into a bounded computational domain and an unbounded exterior domain. On the exterior domain, the Laplace transformation in time and Fourier series in space are applied to achieve the relation of special functions. Then the rational functions are used to approximate the relation of the special functions. Applying the inverse Laplace transformation to a series of simple rational function, we finally obtain the corresponding high-order artificial boundary conditions, where a sequence of auxiliary variables are utilized to avoid the high-order derivatives in respect to time and space. Furthermore, the finite difference method is formulated to discretize the reduced initial–boundary value problem with high-order artificial boundary conditions on a bounded computational domain. Numerical experiments are presented to illustrate the performance of our method. 相似文献
129.
《Expert systems with applications》2014,41(5):2574-2581
We describe in this paper a new methodology for blood alcohol content (BAC) estimation of a subject. Rather than using external devices to determine the BAC value of a subject, we perform a behaviour analysis of this subject using intelligent systems. We monitor the user’s actions in an ordinary task and label those data to various measured BAC values. The obtained data-set is then used to train learning systems to detect alcoholic consumption and perform BAC estimation. We obtain good results on a mono-user base, and lower results with multiple users. We improve the results by combining multiple classifiers and regression algorithms. 相似文献
130.
推荐系统是用来解决当今时代信息过载的重要工具。随着在线社交网络的出现和普及,一些基于网络推荐算法研究的出现,已经引起研究者的广泛关注。信任是社会网络中的重要信息之一,通常用来改进基于社交网络的推荐系统,然而,大多数信任感知的推荐系统忽略了用户有不同行为偏好在不同的兴趣域;本文不仅考虑了用户间特定域信任网络,并且结合推荐项目之间特征属性信息,提出了一种新型社会化推荐算法(H-PMF)。实验表明,H-PMF算法在评分误差和推荐精度上都取得了更好的效果。 相似文献