全文获取类型
收费全文 | 6872篇 |
免费 | 879篇 |
国内免费 | 683篇 |
专业分类
电工技术 | 590篇 |
综合类 | 1255篇 |
化学工业 | 573篇 |
金属工艺 | 195篇 |
机械仪表 | 611篇 |
建筑科学 | 318篇 |
矿业工程 | 113篇 |
能源动力 | 173篇 |
轻工业 | 132篇 |
水利工程 | 219篇 |
石油天然气 | 280篇 |
武器工业 | 89篇 |
无线电 | 789篇 |
一般工业技术 | 1057篇 |
冶金工业 | 92篇 |
原子能技术 | 85篇 |
自动化技术 | 1863篇 |
出版年
2024年 | 29篇 |
2023年 | 71篇 |
2022年 | 121篇 |
2021年 | 159篇 |
2020年 | 187篇 |
2019年 | 211篇 |
2018年 | 214篇 |
2017年 | 228篇 |
2016年 | 309篇 |
2015年 | 245篇 |
2014年 | 397篇 |
2013年 | 439篇 |
2012年 | 548篇 |
2011年 | 497篇 |
2010年 | 378篇 |
2009年 | 394篇 |
2008年 | 442篇 |
2007年 | 468篇 |
2006年 | 409篇 |
2005年 | 390篇 |
2004年 | 303篇 |
2003年 | 303篇 |
2002年 | 219篇 |
2001年 | 219篇 |
2000年 | 206篇 |
1999年 | 161篇 |
1998年 | 142篇 |
1997年 | 137篇 |
1996年 | 117篇 |
1995年 | 84篇 |
1994年 | 74篇 |
1993年 | 65篇 |
1992年 | 57篇 |
1991年 | 42篇 |
1990年 | 41篇 |
1989年 | 43篇 |
1988年 | 30篇 |
1987年 | 15篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1966年 | 1篇 |
1959年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有8434条查询结果,搜索用时 359 毫秒
131.
In this paper, a quasi-Newton-type optimized iterative learning control (ILC)
algorithm is investigated
for a class of discrete linear time-invariant systems. The proposed learning
algorithm is to update the learning gain matrix by a quasi-Newton-type matrix instead of the
inversion of the plant. By means of the mathematical inductive method, the monotone
convergence of the proposed algorithm is analyzed, which shows
that the tracking error monotonously converges to zero after a
finite number of iterations. Compared with the existing optimized ILC
algorithms, due to the superlinear convergence of quasi-Newton method, the proposed learning law operates with a faster
convergent rate and is robust to the ill-condition of the
system model, and thus owns a wide range of applications.
Numerical simulations demonstrate the validity and
effectiveness. 相似文献
132.
论文对一种三平移并联机器人进行了运动学建模,运用矩阵计算方法得到其机构运动学反解,即根据终端执行器的运动规律,求出原动件在单位时间内的位移,进而求得步进电机在单位时间内所发的脉冲数。实验验证该步进电机控制算法的正确性,为并联机器人的运动控制提供了理论方法。 相似文献
133.
134.
The conventional space-time adaptive processing(STAP) method such as the typical sample matrix inversion(SMI)-based STAP method is difficult to implement for a practical system because intense computational complexity arises in calculating the inversion of a space-time covariance matrix directly.According to the block Hermitian matrix property of space-time covariance matrix,a new pulse-order recursive method is proposed in this paper to calculate the inverse covariance matrix for the STAP adaptive weight,which can reduce the computational complexity significantly.The proposed method requires initially calculating the inverse covariance matrix of the first pulse-order recursively based on the block Hermitian matrix property.In the following,the inversion of space-time covariance matrix is obtained recursively based on the previous pulse-order inverse covariance matrix.Next,the STAP adaptive weight is calculated based on the inversion space-time covariance matrix previously obtained.Compared with the conventional SMI-based STAP algorithms,the computational complexity of the proposed method is reduced to more than 50% for the same clutter suppression performance.This method can be applied to practical systems benefiting from small computational complexity and stable clutter suppression performance. 相似文献
135.
为了更好地与复杂多变的非结构化环境进行交互,完成对目标物体的识别和抓取,提出了一种应用于服务机器人平台的基于双目视觉的仿人机械臂控制方法.文中首先用D-H方法对机械臂进行建模,并对这个模型做了改进,给出了一种更加简便的3+1自由度仿人机械臂的逆解算法,采用基于双目视觉与颜色分割的目标识别方法;然后根据识别出的目标三维坐标信息控制机械臂完成抓取任务;最后,本方法在家庭服务机器人上得到了验证,机器人能够完成对目标物体的识别和抓取动作. 相似文献
136.
Turbo码的迭代译码次数越多,译码延时和功耗也越大,通过图像传输的Turbo译码仿真分析,提出按不同比特位迭代次数不同的译码方法,并对各比特位的迭代次数进行优化,结果能使总迭代译码次数减少50%,且能保证译码后的图像效果。 相似文献
137.
In this paper, we survey several recent results that highlight an interplay between a relatively new class of quasiseparable matrices and univariate polynomials. Quasiseparable matrices generalize two classical matrix classes, Jacobi (tridiagonal) matrices and unitary Hessenberg matrices that are known to correspond to real orthogonal polynomials and Szegö polynomials, respectively. The latter two polynomial families arise in a wide variety of applications, and their short recurrence relations are the basis for a number of efficient algorithms. For historical reasons, algorithm development is more advanced for real orthogonal polynomials. Recent variations of these algorithms tend to be valid only for the Szegö polynomials; they are analogues and not generalizations of the original algorithms. 相似文献
138.
Several researchers have recently investigated the connection between reinforcement learning and classification. We are motivated
by proposals of approximate policy iteration schemes without value functions, which focus on policy representation using classifiers
and address policy learning as a supervised learning problem. This paper proposes variants of an improved policy iteration
scheme which addresses the core sampling problem in evaluating a policy through simulation as a multi-armed bandit machine.
The resulting algorithm offers comparable performance to the previous algorithm achieved, however, with significantly less
computational effort. An order of magnitude improvement is demonstrated experimentally in two standard reinforcement learning
domains: inverted pendulum and mountain-car. 相似文献
139.
This research introduces a new optimality criterion for motion planning of wheeled mobile robots based on a cost index that assesses the nearness to singularity of forward and
inverse kinematic models. Slip motions, infinite estimation error and impossible control actions are avoided escaping from singularities. In addition, high amplification of wheel velocity errors and high wheel velocity values are
also avoided by moving far from the singularity. The proposed cost index can be used directly to complement path-planning and motion-planning techniques (e.g. tree graphs, roadmaps, etc.) in order to select the optimal collision-free path or trajectory among several possible solutions. To illustrate the applications of the proposed
approach, an industrial forklift, equivalent to a tricycle-like mobile robot, is considered in a simulated environment. In particular, several results are
validated for the proposed optimality criterion, which are extensively compared to those obtained with other classical optimality criteria, such as shortest-path, time-optimal and minimum-energy. 相似文献
140.