全文获取类型
收费全文 | 8229篇 |
免费 | 815篇 |
国内免费 | 530篇 |
专业分类
电工技术 | 457篇 |
综合类 | 920篇 |
化学工业 | 531篇 |
金属工艺 | 857篇 |
机械仪表 | 1574篇 |
建筑科学 | 565篇 |
矿业工程 | 448篇 |
能源动力 | 64篇 |
轻工业 | 268篇 |
水利工程 | 214篇 |
石油天然气 | 251篇 |
武器工业 | 249篇 |
无线电 | 1001篇 |
一般工业技术 | 612篇 |
冶金工业 | 330篇 |
原子能技术 | 65篇 |
自动化技术 | 1168篇 |
出版年
2024年 | 37篇 |
2023年 | 79篇 |
2022年 | 178篇 |
2021年 | 213篇 |
2020年 | 207篇 |
2019年 | 194篇 |
2018年 | 186篇 |
2017年 | 270篇 |
2016年 | 326篇 |
2015年 | 300篇 |
2014年 | 556篇 |
2013年 | 431篇 |
2012年 | 684篇 |
2011年 | 637篇 |
2010年 | 545篇 |
2009年 | 495篇 |
2008年 | 490篇 |
2007年 | 646篇 |
2006年 | 552篇 |
2005年 | 488篇 |
2004年 | 369篇 |
2003年 | 317篇 |
2002年 | 266篇 |
2001年 | 220篇 |
2000年 | 237篇 |
1999年 | 140篇 |
1998年 | 103篇 |
1997年 | 93篇 |
1996年 | 69篇 |
1995年 | 50篇 |
1994年 | 51篇 |
1993年 | 34篇 |
1992年 | 21篇 |
1991年 | 22篇 |
1990年 | 14篇 |
1989年 | 20篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1984年 | 7篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1959年 | 2篇 |
排序方式: 共有9574条查询结果,搜索用时 15 毫秒
41.
42.
43.
介绍了抽动式衬套正挤切边工艺、模具结构及设计要点 ,该模具结构简单合理 ,能在1台压机上依次完成挤压成形和切边两道工序 ,效率较高 相似文献
44.
45.
46.
47.
Variable precision intuitionistic fuzzy rough set model and applications based on conflict distance 下载免费PDF全文
Due to the complexity and uncertainty of the physical world, as well as the limitation of human ability to comprehend, it is very difficult for any single method of uncertainty to effectively deal with the decision‐making problem that exists in real life. So, it is natural for us to think about incorporating the advantages of various theories of uncertainty to develop a more powerful hybrid method of soft decision‐making. In view of this recognition, the thought and method of intuitionistic fuzzy sets and variable precision rough sets are used to construct a novel intuitionistic fuzzy rough set model. With respect to the fact that the information system is intuitionistic fuzzy, the idea of measuring intuitionistic fuzzy similarity is used to define conflict distance. After that, this concept is combined with the variable precision rough sets so that a variable precision intuitionistic fuzzy rough set model is established, and its properties are investigated. After proposing an attribute reduction algorithm based on variable precision intuitionistic fuzzy rough sets, a case study is used to verify the feasibility and effectiveness of our novel model. The results show that our model indeed improves the classification ability of earlier models and possesses some ability to tolerate faults through adjusting the parameter λ and the confidence threshold β; it realizes the correct classification and extracts the decision rules. 相似文献
48.
49.
High‐precision formation control of nonlinear multi‐agent systems with switching topologies: A learning approach 下载免费PDF全文
Arbitrary high precision is considered one of the most desirable control objectives in the relative formation for many networked industrial applications, such as flying spacecrafts and mobile robots. The main purpose of this paper is to present design guidelines of applying the iterative schemes to develop distributed formation algorithms in order to achieve this control objective. If certain conditions are met, then the control input signals can be learned by the developed algorithms to accomplish the desired formations with arbitrary high precision. The systems under consideration are a class of multi‐agent systems under directed networks with switching topologies. The agents have discrete‐time affine nonlinear dynamics, but their state functions do not need to be identical. It is shown that the learning processes resulting from the relative output formation of multi‐agent systems can converge exponentially fast with the increase of the iteration number. In particular, this work induces a distributed algorithm that can simultaneously achieve the desired relative output formation between agents and regulate the movement of multi‐agent formations as desired along the time axis. The illustrative numerical simulations are finally performed to demonstrate the effectiveness and performance of the proposed distributed formation algorithms. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
50.
An appropriate assessment of end-to-end network performance presumes highly efficient time tracking and measurement with precise time control of the stopping and resuming of program operation. In this paper, a novel approach to solving the problems of highly efficient and precise time measurements on PC-platforms and on ARM-architectures is proposed. A new unified High Performance Timer and a corresponding software library offer a unified interface to the known time counters and automatically identify the fastest and most reliable time source, available in the user space of a computing system. The research is focused on developing an approach of unified time acquisition from the PC hardware and accordingly substituting the common way of getting the time value through Linux system calls. The presented approach provides a much faster means of obtaining the time values with a nanosecond precision than by using conventional means. Moreover, it is capable of handling the sequential time value, precise sleep functions and process resuming. This ability means the reduction of wasting computer resources during the execution of a sleeping process from 100% (busy-wait) to 1-1.5%, whereas the benefits of very accurate process resuming times on long waits are maintained. 相似文献