全文获取类型
收费全文 | 37090篇 |
免费 | 5085篇 |
国内免费 | 3855篇 |
专业分类
电工技术 | 3730篇 |
综合类 | 5538篇 |
化学工业 | 2528篇 |
金属工艺 | 943篇 |
机械仪表 | 2222篇 |
建筑科学 | 1909篇 |
矿业工程 | 774篇 |
能源动力 | 819篇 |
轻工业 | 1779篇 |
水利工程 | 1066篇 |
石油天然气 | 1173篇 |
武器工业 | 554篇 |
无线电 | 5408篇 |
一般工业技术 | 3794篇 |
冶金工业 | 858篇 |
原子能技术 | 299篇 |
自动化技术 | 12636篇 |
出版年
2024年 | 157篇 |
2023年 | 549篇 |
2022年 | 1030篇 |
2021年 | 1187篇 |
2020年 | 1326篇 |
2019年 | 1302篇 |
2018年 | 1167篇 |
2017年 | 1491篇 |
2016年 | 1642篇 |
2015年 | 1739篇 |
2014年 | 2295篇 |
2013年 | 2963篇 |
2012年 | 2764篇 |
2011年 | 2973篇 |
2010年 | 2266篇 |
2009年 | 2315篇 |
2008年 | 2315篇 |
2007年 | 2610篇 |
2006年 | 2094篇 |
2005年 | 1853篇 |
2004年 | 1550篇 |
2003年 | 1305篇 |
2002年 | 1134篇 |
2001年 | 995篇 |
2000年 | 843篇 |
1999年 | 702篇 |
1998年 | 521篇 |
1997年 | 516篇 |
1996年 | 395篇 |
1995年 | 358篇 |
1994年 | 289篇 |
1993年 | 236篇 |
1992年 | 200篇 |
1991年 | 183篇 |
1990年 | 161篇 |
1989年 | 119篇 |
1988年 | 80篇 |
1987年 | 62篇 |
1986年 | 39篇 |
1985年 | 32篇 |
1984年 | 45篇 |
1983年 | 44篇 |
1982年 | 32篇 |
1981年 | 31篇 |
1980年 | 26篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 14篇 |
1976年 | 7篇 |
1959年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
211.
This paper contributes to extend the minimax disparity to determine the ordered weighted averaging (OWA) model based on linear programming. It introduces the minimax disparity approach between any distinct pairs of the weights and uses the duality of linear programming to prove the feasibility of the extended OWA operator weights model. The paper finishes with an open problem. 相似文献
212.
Yu. I. Petunin E. A. Djomina D. A. Klyushin M. Yu. Savkina 《Cybernetics and Systems Analysis》2006,42(3):449-455
Spline regression is used to analyze the influence of radiation on the cancer probability in a group of participants of Chernobyl
accident mitigation, depending on the exposure dose. A new method is proposed to approximate modified polygons by linear splines
with two nodes. An algorithm for the identification of a transition point is outlined.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 168–176, May–June 2006. 相似文献
213.
214.
A simple and computationally efficient method of determining the transfer function and other characteristics of systems with multiple inputs and multiple outputs (MIMO systems) described by autoregression equations is proposed. The method is based on the use of the discrete Fourier transformation. The algorithm is highly suitable for computer implementation. The efficiency and simplicity of the method are illustrated using the example of a system with three inputs and three outputs. The proposed concept may be applied to systems described by the autoregression sliding mean. 相似文献
215.
Stability of large-scale coal-fired MHD channels is studied by (1) linearized stability analysis, and (2) time-dependent 1-D analysis. The channel length is 15 m with 600 electrode pairs, and the output power ranges from 220.6 MW through 258.7 MW. Linearized stability analyses show that the Faraday channels operated with fixed loading resistance are stable, whereas the two waves of u and u–a (u, a: gas and sound velocity) become unstable in the Faraday channel with fixed loading factor. Two waves of u and u–a are unstable in the diagonal channel with fixed loading current and the u + a wave becomes unstable in the diagonal channel with fixed electrode current. Time-dependent one-dimensional analyses indicate that the Faraday channels with fixed load resistance are smooth without growth of fluctuation. The diagonal channels with fixed electrode current are smooth with no fluctuation, though the linear theory indicates that the u + a wave is unstable. The diagonal channel with fixed load current suffers large disturbance along the latter half of the channel, being consistent with the linearized analysis which indicates that the u - a and u waves are unstable. 相似文献
216.
From the principle of of the Domain Decomposition Method (DDM), we analyse the 2nd-order linear elliptic partial differential problems and link the Separated-Layers Algorithm (SLA) with DDM. The mathematical properties of SLA and numerical example are presented to obtain satisfactory computation results. For general linear differential ones, also are the structure of SLA and its characteristics discussed. 相似文献
217.
根据引信安全系统理论和状态空间分析方法,研究了引信安全系统的物理方程及其无量纲归一化方程的动态特性不变性,各保险要素之间的独立性,安全系统解除保险过程的时滞性和平衡态及其稳定性,并对这些性质给出了严格的定义。这些性质和定义为深入研究引信安全系统及其解除保险过程,提供了理论依据和有效方法。 相似文献
218.
V. V. Semenov 《Cybernetics and Systems Analysis》2007,43(2):246-252
For infinitely dimensional convex vector maximization problems, it is proved that there exists, under certain conditions,
an arbitrarily small additive perturbation of the performance criterion by a linear continuous operator such that the perturbed
problem has efficient solutions.
The study was sponsored by the Ukrainian State Fund for Basic Research
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 105–114, March–April 2007. 相似文献
219.
The oil crisis of the 1970s has increased the concern about the continuity of oil imports flow to major oil-importing developed countries. Numerous policy measures including electricity demand-side management (DSM) programs have been adopted in such countries. These measures aim at reducing the growing need for electricity power that increases the dependency on imported foreign oil and damages the environment. On the other hand, the perception that energy can be obtained at very low cost in oil-rich countries led to less attention being paid to the potential of DSM policies in these countries. This paper discusses such potential using the case of the United Arab Emirates (UAE). Since air conditioning is a major source of electric energy consumption, the relationship between climate conditions and electric energy consumption is considered. An electricity demand model is constructed using time series techniques. The fitted model seems to represent these relationships rather well. Forecasts for electricity consumption using the estimated model indicate that a small reduction in cooling degrees requirement might induce a significant reduction in electric energy demand. Hence, a DSM program is proposed with policy actions to include, among others, measures to reduce cooling degrees requirement. 相似文献
220.
广义汉明重量下限函数Lr(j,d)的新证明 总被引:3,自引:0,他引:3
通过几个引理,对广义汉明重量下限函数Lr(j,d)的有限和表达式给出了一个思路简单的证明方法。给出了取整数函数[x],[x]的一些运算性质。 相似文献