全文获取类型
收费全文 | 28055篇 |
免费 | 3600篇 |
国内免费 | 2383篇 |
专业分类
电工技术 | 3622篇 |
技术理论 | 3篇 |
综合类 | 3380篇 |
化学工业 | 3064篇 |
金属工艺 | 1598篇 |
机械仪表 | 2545篇 |
建筑科学 | 1565篇 |
矿业工程 | 931篇 |
能源动力 | 791篇 |
轻工业 | 905篇 |
水利工程 | 561篇 |
石油天然气 | 860篇 |
武器工业 | 498篇 |
无线电 | 3466篇 |
一般工业技术 | 2905篇 |
冶金工业 | 1057篇 |
原子能技术 | 344篇 |
自动化技术 | 5943篇 |
出版年
2024年 | 172篇 |
2023年 | 437篇 |
2022年 | 654篇 |
2021年 | 812篇 |
2020年 | 971篇 |
2019年 | 949篇 |
2018年 | 831篇 |
2017年 | 1061篇 |
2016年 | 1157篇 |
2015年 | 1138篇 |
2014年 | 1682篇 |
2013年 | 1709篇 |
2012年 | 1872篇 |
2011年 | 1979篇 |
2010年 | 1546篇 |
2009年 | 1483篇 |
2008年 | 1588篇 |
2007年 | 1855篇 |
2006年 | 1761篇 |
2005年 | 1515篇 |
2004年 | 1297篇 |
2003年 | 1113篇 |
2002年 | 1042篇 |
2001年 | 855篇 |
2000年 | 798篇 |
1999年 | 668篇 |
1998年 | 474篇 |
1997年 | 451篇 |
1996年 | 375篇 |
1995年 | 313篇 |
1994年 | 304篇 |
1993年 | 261篇 |
1992年 | 183篇 |
1991年 | 138篇 |
1990年 | 127篇 |
1989年 | 92篇 |
1988年 | 74篇 |
1987年 | 42篇 |
1986年 | 39篇 |
1985年 | 21篇 |
1984年 | 36篇 |
1983年 | 25篇 |
1982年 | 27篇 |
1981年 | 14篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1960年 | 5篇 |
1959年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
面对日益突出的城市静态交通问题,针对普陀区所处的地理位置和发展形势,提出了在普陀区实施静态交通规划(包括技术路线、政策研究及相关的经济分析方法)的初步构想。 相似文献
52.
53.
This article deals with the kinetics of two-step anionic polymerization by way of a non-steady state method. Several molecular parameters can be evaluated using the formulae developed. A bimodal molecular weight distribution function for the resulting polymer is derived from the set of kinetic differential equations, which is in agreement with the experimental data reported. 相似文献
54.
Estimating the state of a nonlinear stochastic system (observed through a nonlinear noisy measurement channel) has been the goal of considerable research to solve both filtering and control problems. In this paper, an original approach to the solution of the optimal state estimation problem by means of neural networks is proposed, which consists in constraining the state estimator to take on the structure of a multilayer feedforward network. Both non-recursive and recursive estimation schemes are considered, which enable one to reduce the original functional problem to a nonlinear programming one. As this reduction entails approximations for the optimal estimation strategy, quantitative results on the accuracy of such approximations are reported. Simulation results confirm the effectiveness of the proposed method. 相似文献
55.
可分2-D系统是一类具有良好特性的重要的特殊2-D系统,它在多方面均有重要的应用.本文在已有结果的基础上对具有可分性的2-D多输入多输出系统在再实现问题、渐近稳定性代数判据、状态观测器设计等方面进行了较为广泛的研究,得到了许多较好的结果. 相似文献
56.
固相缩聚共聚酯的熔融行为和结晶速率研究 总被引:1,自引:0,他引:1
通过固相缩聚合成了两种不同结构的高分子量共聚酯,研究了样品的熔融行为和结晶速率。研究发现,共聚酯的熔融峰随着固相聚合温度和时间的变化而与纯PET有明显的差别,共聚酯泊结晶速率与慢于纯PET的结晶速率。 相似文献
57.
58.
A mixed mode digital/analog special purpose VLSI hardware implementation of an associative memory with neural architecture is presented. The memory concept is based on a matrix architecture with binary storage elements holding the connection weights. To enhance the processing speed analog circuit techniques are applied to implement the algorithm for the association. To keep the memory density as high as possible two design strategies are considered. First, the number of transistors per storage element is kept to a minimum. In this paper a circuit technique that uses a single 6-transistor cell for weight storage and analog signal processing is proposed. Second, the device precision has been chosen to a moderate level to save area as much as possible. Since device mismatch limits the performance of analog circuits, the impact of device precision on the circuit performance is explicitly discussed. It is shown that the device precision limits the number of rows activated in parallel. Since the input vector as well as the output vector are considered to be sparsely coded it is concluded, that even for large matrices the proposed circuit technique is appropriate and ultra large scale integration with a large number of connection weights is feasible. 相似文献
59.
60.
Design and Implementation of a Flexible Manufacturing Control System Using Neural Network 总被引:1,自引:0,他引:1
Magdy M. Abdelhameed Farid A. Tolbah 《International Journal of Flexible Manufacturing Systems》2002,14(3):263-279
Design and implementation of a sequential controller based on the concept of artificial neural networks for a flexible manufacturing system are presented. The recurrent neural network (RNN) type is used for such a purpose. Contrary to the programmable controller, an RNN-based sequential controller is based on a definite mathematical model rather than depending on experience and trial and error techniques. The proposed controller is also more flexible because it is not limited by the restrictions of the finite state automata theory. Adequate guidelines of how to construct an RNN-based sequential controller are presented. These guidelines are applied to different case studies. The proposed controller is tested by simulations and real-time experiments. These tests prove the successfulness of the proposed controller performances. Theoretical as well as experimental results are presented and discussed indicating that the proposed design procedure using Elman's RNN can be effective in designing a sequential controller for event-based type manufacturing systems. In addition, the simulation results assure the effectiveness of the proposed controller to outperform the effect of noisy inputs. 相似文献