全文获取类型
收费全文 | 5459篇 |
免费 | 384篇 |
国内免费 | 280篇 |
专业分类
电工技术 | 235篇 |
综合类 | 803篇 |
化学工业 | 251篇 |
金属工艺 | 46篇 |
机械仪表 | 175篇 |
建筑科学 | 247篇 |
矿业工程 | 29篇 |
能源动力 | 111篇 |
轻工业 | 263篇 |
水利工程 | 100篇 |
石油天然气 | 36篇 |
武器工业 | 13篇 |
无线电 | 559篇 |
一般工业技术 | 784篇 |
冶金工业 | 181篇 |
原子能技术 | 50篇 |
自动化技术 | 2240篇 |
出版年
2024年 | 10篇 |
2023年 | 53篇 |
2022年 | 57篇 |
2021年 | 80篇 |
2020年 | 116篇 |
2019年 | 123篇 |
2018年 | 119篇 |
2017年 | 132篇 |
2016年 | 160篇 |
2015年 | 158篇 |
2014年 | 258篇 |
2013年 | 418篇 |
2012年 | 330篇 |
2011年 | 394篇 |
2010年 | 270篇 |
2009年 | 334篇 |
2008年 | 328篇 |
2007年 | 319篇 |
2006年 | 295篇 |
2005年 | 245篇 |
2004年 | 234篇 |
2003年 | 202篇 |
2002年 | 203篇 |
2001年 | 145篇 |
2000年 | 148篇 |
1999年 | 124篇 |
1998年 | 127篇 |
1997年 | 106篇 |
1996年 | 95篇 |
1995年 | 87篇 |
1994年 | 68篇 |
1993年 | 61篇 |
1992年 | 44篇 |
1991年 | 37篇 |
1990年 | 35篇 |
1989年 | 34篇 |
1988年 | 23篇 |
1987年 | 18篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 21篇 |
1983年 | 17篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1976年 | 9篇 |
1965年 | 5篇 |
1963年 | 4篇 |
排序方式: 共有6123条查询结果,搜索用时 0 毫秒
121.
Estimators and tests based on likelihood depth for one-parametric copulas are given. For the Gaussian and Gumbel copulas, it is shown that the maximum depth estimators are biased. They can be corrected and the new estimators are robust against contamination. For testing, simplicial likelihood depth is considered. Because of the bias of the maximum depth estimator, simplicial likelihood depth is not a degenerated U-statistic so that easily asymptotic α-level tests can be derived for arbitrary hypotheses. Tests are in particular investigated for the one-sided alternatives. Simulation studies for the Gaussian and Gumbel copulas show that the power of the first test is rather good, but the latter one has to be improved, which is also done here. The new tests are robust against contamination. 相似文献
122.
We show that for some special functions (called k-multigrid equidistributed functions), we can compute the limit of the frequency of patterns in the discretization of their graph, when the resolution tends to zero. This result is applied to parabolas. We deduce also that local length estimators almost never converge to the length for the parabolas. 相似文献
123.
124.
In this paper we derive guaranteed gain, sector, and disk margins for nonlinear optimal and inverse optimal regulators that minimize a nonlinear-nonquadratic performance criterion involving cross-weighting terms. Specifically, sufficient conditions that guarantee gain, sector, and disk margins are given in terms of the state, control, and cross-weighting nonlinear-nonquadratic weighting functions. The proposed results provide a generalization of the “meaningful” inverse optimal nonlinear regulator stability margins as well as the classical linear-quadratic optimal regulator gain and phase margins. 相似文献
125.
A team algorithm based on piecewise quadratic simultaneous Lyapunov functions for robust stability analysis and control design of uncertain time‐varying linear systems is introduced. The objective is to use robust stability criteria that are less conservative than the usual quadratic stability criterion. The use of piecewise quadratic Lyapunov functions leads to a non‐convex optimization problem, which is decomposed into a convex subproblem in a selected subset of decision variables, and a lower‐dimensional non‐convex subproblem in the remaining decision variables. A team algorithm that combines genetic algorithms (GA) for the non‐convex subproblem and interior‐point methods for the solution of linear matrix inequalities (LMI), which form the convex subproblem, is proposed. Numerical examples are given, showing the advantages of the proposed method. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
126.
127.
The inverted pendulum has been used as a benchmark for motivating the study of nonlinear control techniques. We propose a simple controller for balancing the inverted pendulum and raise it to its upper equilibrium position while the cart displacement is brought to zero. The control strategy is based on an energy approach of the cart and pendulum system. 相似文献
128.
Based on the genetic algorithm (GA), an approach is proposed for simultaneous design of membership functions and fuzzy control rules since these two components are interdependent in designing a fuzzy logic controller (FLC). With triangular membership functions, the left and right widths of these functions, the locations of their peaks, and the fuzzy control rules corresponding to every possible combination of input linguistic variables are chosen as parameters to be optimized. By using a proportional scaling method, these parameters are then transformed into real-coded chromosomes, over which the offspring are generated by rank-based reproduction, convex crossover, and nonuniform mutation. Meanwhile, the concept of enlarged sampling space is used to expedite the convergence of the evolutionary process. To show the feasibility and validity of the proposed method, a cart-centering example will be given. The simulation results will show that the designed FLC can drive the cart system from any given initial state to the desired final state even when the cart mass varies within a wide range. 相似文献
129.
Recursive algorithm and accurate computation of dyadic Green’s functions for stratified uniaxial anisotropic media 总被引:1,自引:0,他引:1
A recursive algorithm is adopted for the computation of dyadic Green's functions in three-dimensional stratified uniaxial anisotropic media with arbitrary number of layers. Three linear equation groups for computing the coefficients of the Sommerfeld integrals are obtained according to the continuity condition of electric and magnetic fields across the interface between different layers, which are in correspondence with the TM wave produced by a vertical unit electric dipole and the TE or TM wave produced by a horizontal unit electric dipole, respectively. All the linear equation groups can be solved via the recursive algorithm. The dyadic Green's functions with source point and field point being in any layer can be conveniently obtained by merely changing the position of the elements within the source term of the linear equation groups. The problem of singularities occurring in the Sommerfeld integrals is efficiently solved by deforming the integration path in the complex plane. The expression of the dyadic Green's functions provided by this paper is terse in form and is easy to be programmed, and it does not overflow. Theoretical analysis and numerical examples show the accuracy and effectivity of the algorithm. 相似文献
130.
本文介绍了在容错分布、量子密码学中的密钥分配以及流密码中的随机序列产生等领域都有着广泛应用的一类多输出布尔函数——弹性函数。弹性函数和0,1上多维空间的正交分划(一个正交矩阵组)是一致的。在此基础上,介绍了弹性函数的正交分划的递归构造方法和简单计数。 相似文献