全文获取类型
收费全文 | 89461篇 |
免费 | 6835篇 |
国内免费 | 3571篇 |
专业分类
电工技术 | 4932篇 |
技术理论 | 5篇 |
综合类 | 5710篇 |
化学工业 | 15725篇 |
金属工艺 | 5511篇 |
机械仪表 | 5496篇 |
建筑科学 | 7860篇 |
矿业工程 | 2579篇 |
能源动力 | 2376篇 |
轻工业 | 5368篇 |
水利工程 | 1565篇 |
石油天然气 | 5255篇 |
武器工业 | 684篇 |
无线电 | 9343篇 |
一般工业技术 | 10683篇 |
冶金工业 | 4508篇 |
原子能技术 | 1068篇 |
自动化技术 | 11199篇 |
出版年
2024年 | 359篇 |
2023年 | 1493篇 |
2022年 | 2420篇 |
2021年 | 3368篇 |
2020年 | 2623篇 |
2019年 | 2183篇 |
2018年 | 2536篇 |
2017年 | 2874篇 |
2016年 | 2456篇 |
2015年 | 3263篇 |
2014年 | 4126篇 |
2013年 | 5061篇 |
2012年 | 5548篇 |
2011年 | 5927篇 |
2010年 | 5037篇 |
2009年 | 4968篇 |
2008年 | 4762篇 |
2007年 | 4588篇 |
2006年 | 4885篇 |
2005年 | 4347篇 |
2004年 | 2904篇 |
2003年 | 2505篇 |
2002年 | 2304篇 |
2001年 | 2030篇 |
2000年 | 2304篇 |
1999年 | 2686篇 |
1998年 | 2187篇 |
1997年 | 1787篇 |
1996年 | 1832篇 |
1995年 | 1489篇 |
1994年 | 1216篇 |
1993年 | 863篇 |
1992年 | 709篇 |
1991年 | 568篇 |
1990年 | 409篇 |
1989年 | 348篇 |
1988年 | 282篇 |
1987年 | 190篇 |
1986年 | 131篇 |
1985年 | 89篇 |
1984年 | 60篇 |
1983年 | 39篇 |
1982年 | 40篇 |
1981年 | 34篇 |
1980年 | 26篇 |
1979年 | 7篇 |
1978年 | 2篇 |
1965年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
Xiang Zhou 《Information Processing Letters》2008,108(1):3-9
In this article, with Ehrenfeucht-Fraïssé games we prove that Δ1≠Δ0 on BFR, which implies Δ≠Δ0 on BFR, and thus solve an open problem raised by Albert Atserias in his dissertation (Δ0,Δ1,Δ are fragments of first order logic and BFR is a class of finite sets which in essence is equivalent to a class of finite pure arithmetic structures with built-in BIT predicate). 相似文献
103.
104.
Zhou Shang-Ming Gan John Q. 《Knowledge and Data Engineering, IEEE Transactions on》2009,21(8):1191-1204
In this paper, a method for constructing Takagi-Sugeno (TS) fuzzy system from data is proposed with the objective of preserving TS submodel comprehensibility, in which linguistic modifiers are suggested to characterize the fuzzy sets. A good property held by the proposed linguistic modifiers is that they can broaden the cores of fuzzy sets while contracting the overlaps of adjoining membership functions (MFs) during identification of fuzzy systems from data. As a result, the TS submodels identified tend to dominate the system behaviors by automatically matching the global model (GM) in corresponding subareas, which leads to good TS model interpretability while producing distinguishable input space partitioning. However, the GM accuracy and model interpretability are two conflicting modeling objectives, improving interpretability of fuzzy models generally degrades the GM performance of fuzzy models, and vice versa. Hence, one challenging problem is how to construct a TS fuzzy model with not only good global performance but also good submodel interpretability. In order to achieve a good tradeoff between GM performance and submodel interpretability, a regularization learning algorithm is presented in which the GM objective function is combined with a local model objective function defined in terms of an extended index of fuzziness of identified MFs. Moreover, a parsimonious rule base is obtained by adopting a QR decomposition method to select the important fuzzy rules and reduce the redundant ones. Experimental studies have shown that the TS models identified by the suggested method possess good submodel interpretability and satisfactory GM performance with parsimonious rule bases. 相似文献
105.
Xiang Li Ling Feng Lizhu Zhou Yuanchun Shi 《Knowledge and Data Engineering, IEEE Transactions on》2009,21(6):910-924
The rapid evolution of information and communication technology opens a wide spectrum of opportunities to change our surroundings into an Ambient Intelligent (AmI) world. AmI is a vision of future information society, where people are surrounded by a digital environment that is sensitive to their needs, personalized to their requirements, anticipatory of their behavior, and responsive to their presence. It emphasizes on greater user friendliness, user empowerment, and more effective service support, with an aim to bring information and communication technology to everyone, every home, every business, and every school, thus improving the quality of human life. AmI unprecedentedly enhances learning experiences by endowing the users with the opportunities of learning in context, a breakthrough from the traditional education settings. In this survey paper, we examine some major characteristics of an AmI learning environment. To deliver a feasible and effective solution to ambient learning, we overview a few latest developed enabling technologies in context awareness and interactive learning. Associated practices are meanwhile reported. We also describe our experience in designing and implementing a smart class prototype, which allows teachers to simultaneously instruct both local and remote students in a context-aware and natural way. 相似文献
106.
107.
108.
基于OpenGL进行导弹飞行过程仿真,研究了交互界面的设计技术、特殊效果产生技术、模型的数据驱动及视点变化技术和碰撞检测技术. 相似文献
109.
Systematic errors in phase-measuring profilometry that are introduced by the modulation transfer function of a digital image-acquisition device are analyzed. New phase expressions and phase-deviation formulas are given. The results for simulations and experiments demonstrate that the algorithm of phase-measuring profilometry cannot be regarded as a point-to-point operation. To obtain precise results, an optimum scheme for setting the measurement system is also proposed. 相似文献
110.
A coplanar refractive-diffractive doublet array employing surface-relief diffractive phase elements embedded within poly(methyl methacrylate) microlenses is introduced as an optomechanical building block for optoelectronic integrated systems. The design method, fabrication technology, and results are described. Coplanarity of the quadratic- and linear-phase elements constituting the doublet can reduce optomechanical complexity in applications to unguided optical interconnects. 相似文献