全文获取类型
收费全文 | 7128篇 |
免费 | 1282篇 |
国内免费 | 1379篇 |
专业分类
电工技术 | 405篇 |
综合类 | 1128篇 |
化学工业 | 107篇 |
金属工艺 | 89篇 |
机械仪表 | 505篇 |
建筑科学 | 110篇 |
矿业工程 | 108篇 |
能源动力 | 64篇 |
轻工业 | 82篇 |
水利工程 | 71篇 |
石油天然气 | 59篇 |
武器工业 | 40篇 |
无线电 | 796篇 |
一般工业技术 | 365篇 |
冶金工业 | 49篇 |
原子能技术 | 12篇 |
自动化技术 | 5799篇 |
出版年
2024年 | 156篇 |
2023年 | 365篇 |
2022年 | 508篇 |
2021年 | 460篇 |
2020年 | 312篇 |
2019年 | 231篇 |
2018年 | 233篇 |
2017年 | 266篇 |
2016年 | 273篇 |
2015年 | 330篇 |
2014年 | 384篇 |
2013年 | 405篇 |
2012年 | 533篇 |
2011年 | 531篇 |
2010年 | 422篇 |
2009年 | 463篇 |
2008年 | 486篇 |
2007年 | 461篇 |
2006年 | 434篇 |
2005年 | 365篇 |
2004年 | 290篇 |
2003年 | 262篇 |
2002年 | 194篇 |
2001年 | 193篇 |
2000年 | 162篇 |
1999年 | 165篇 |
1998年 | 123篇 |
1997年 | 133篇 |
1996年 | 94篇 |
1995年 | 94篇 |
1994年 | 77篇 |
1993年 | 61篇 |
1992年 | 54篇 |
1991年 | 45篇 |
1990年 | 43篇 |
1989年 | 33篇 |
1988年 | 35篇 |
1987年 | 10篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1984年 | 16篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1976年 | 8篇 |
1975年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有9789条查询结果,搜索用时 14 毫秒
71.
本文首次定义了近完全图的概念并采用先分解后组合的方法研究出一种边数很多、接近于完全图的不同构图的确定方法及其数目的比较算法,给出了判断定理及其证明和应用。 相似文献
72.
He Xinhua Gong Yunzhan 《电子科学学刊(英文版)》1996,13(1):68-73
This paper presents the techniques of verification and Test Generation(TG) for sequential machines (Finite State Machines, FSMs) based on state traversing of State Transition Graph(STG). The problems of traversing, redundancy and transition fault model are identified. In order to achieve high fault coverage collapsing testing is proposed. Further, the heuristic knowledge for speeding up verification and TG are described. 相似文献
73.
本文首先指出坚韧度是可以用来刻划图的连通性,因而能广泛地应用于通讯网络可靠性等有关领域的研究,进而,研究了坚韧度的自身特性,诸如取值范围、存在性问题、计数问题以及计算问题等。 相似文献
74.
轮式车辆动力传动系统动态特性键合图建模与仿真的研究 总被引:2,自引:0,他引:2
在深入分析车辆纵向运动时动力传动系统各单元动态特性及其相互作用的基础上,运用键合图理论构造了车辆动力传动系统较完整的动态模型,并用实例进行了仿真和试验验证。研究结果表明,所建模型和仿真可以较准确地反映系统的动态特性。 相似文献
75.
76.
在超大集成电路的设计过程中,库单元绑定是非常重要的一环。它的目标是通过特定的方法,把一组布尔网络表述的逻辑功能能用具体的库单元实现。逻辑分解是这一过程中非常重要的一步,经分解产生的主题图质量的好坏直接影响到最后的设计结果。本文针对主题图的面积优化问题,提出了“再分解”这一新设计方法,该方法采用“逻辑变换”技术,使主题图中门的娄量尽量减少,从而达到减小实际网表面积的目的。 相似文献
77.
A new single channel, time division multiple access (TDMA)-based broadcast scheduling protocol, termed the Five-Phase Reservation Protocol (FPRP), is presented for mobile ad hoc networks. The protocol jointly and simultaneously performs the tasks of channel access and node broadcast scheduling. The protocol allows nodes to make reservations within TDMA broadcast schedules. It employs a contention-based mechanism with which nodes compete with each other to acquire TDMA slots. The FPRP is free of the hidden terminal problem, and is designed such that reservations can be made quickly and efficiently with negligible probability of conflict. It is fully-distributed and parallel (a reservation is made through a localized conversation between nodes in a 2-hop neighborhood), and is thus scalable. A multihop ALOHA policy is developed to support the FPRP. This policy uses a multihop, pseudo-Bayesian algorithm to calculate contention probabilities and enable faster convergence of the reservation procedure. The performance of the protocol, measured in terms of scheduling quality, scheduling overhead and robustness in the presence of nodal mobility, has been studied via simulations. The results showed that the protocol works very well in all three aspects. Some future work and applications are also discussed. 相似文献
78.
Waveband switching (WBS) is a promising technique to reduce the switching and transmission costs in the optical domain of a wavelength-division multiplexing (WDM) network. This paper considers the problem of provisioning dynamic traffic using WBS in a WDM mesh network. The network of interest is a homogeneous WBS network, where each node has the functionality of WBS. The problem is called the dynamic WBS problem, which involves searching waveband-routes or wavelength-routes for the dynamically arriving traffic requests. The objective is to minimize the total switching and transmission costs in the optical domain. To solve the dynamic WBS problem, an auxiliary graph model capturing the network state is proposed. Based on the auxiliary graph, two heuristic on-line WBS algorithms with different waveband grouping policies are proposed, namely the wavelength-first WBS algorithm based on the auxiliary graph (WFAUG) and the waveband-first WBS algorithm based on the auxiliary graph (BFAUG). Simulation results indicate that WBS is an attractive technique which reduces the overall switching and transmission costs by up to 30% in the network. The results also show that the WFAUG algorithm outperforms the BFAUG algorithm in terms of port savings and cost savings. 相似文献
79.
This paper proposes an efficient inter- ference mitigation and joint decoding scheme for uplink LDPC-coded relay cooperation over a Rayleigh fading channel, where a concatenation of Minimum-mean-squared error linear detectors (MMSE) and BP-based joint itera- tire decoding based on the introduced treble-layer Tanner graph are effectively designed to filter and decode the cor- rupted received sequence at a base station. It is demon- strated by theoretical analysis and numerical simulations that the proposed design can well combine the gains from coding and diversity, which consequently leads to a sig- nificant performance improvement over the conventional cooperation system under the same conditions. 相似文献
80.