全文获取类型
收费全文 | 102962篇 |
免费 | 10578篇 |
国内免费 | 5756篇 |
专业分类
电工技术 | 7365篇 |
技术理论 | 1篇 |
综合类 | 8120篇 |
化学工业 | 15454篇 |
金属工艺 | 6146篇 |
机械仪表 | 6934篇 |
建筑科学 | 8347篇 |
矿业工程 | 3285篇 |
能源动力 | 2634篇 |
轻工业 | 8068篇 |
水利工程 | 2301篇 |
石油天然气 | 4941篇 |
武器工业 | 1008篇 |
无线电 | 12149篇 |
一般工业技术 | 11199篇 |
冶金工业 | 4235篇 |
原子能技术 | 1265篇 |
自动化技术 | 15844篇 |
出版年
2024年 | 224篇 |
2023年 | 1499篇 |
2022年 | 3017篇 |
2021年 | 4276篇 |
2020年 | 3321篇 |
2019年 | 2710篇 |
2018年 | 2961篇 |
2017年 | 3400篇 |
2016年 | 3115篇 |
2015年 | 4755篇 |
2014年 | 5685篇 |
2013年 | 6826篇 |
2012年 | 7762篇 |
2011年 | 8205篇 |
2010年 | 7514篇 |
2009年 | 7350篇 |
2008年 | 7070篇 |
2007年 | 6738篇 |
2006年 | 6170篇 |
2005年 | 5219篇 |
2004年 | 3483篇 |
2003年 | 2823篇 |
2002年 | 2579篇 |
2001年 | 2259篇 |
2000年 | 1888篇 |
1999年 | 1758篇 |
1998年 | 1168篇 |
1997年 | 1029篇 |
1996年 | 903篇 |
1995年 | 750篇 |
1994年 | 604篇 |
1993年 | 452篇 |
1992年 | 360篇 |
1991年 | 267篇 |
1990年 | 235篇 |
1989年 | 194篇 |
1988年 | 153篇 |
1987年 | 98篇 |
1986年 | 92篇 |
1985年 | 45篇 |
1984年 | 51篇 |
1983年 | 28篇 |
1982年 | 37篇 |
1981年 | 21篇 |
1980年 | 42篇 |
1979年 | 22篇 |
1978年 | 18篇 |
1977年 | 15篇 |
1974年 | 14篇 |
1951年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Niu Hao Yang Dan-Lei Pu Yuan Wang Dan Wang Jie-Xin 《Journal of Materials Science》2022,57(10):5788-5804
Journal of Materials Science - Nanocomposites have been used in various industries due to their excellent properties. For some of them, high filler content (over 50 wt%) is beneficial to improving... 相似文献
2.
3.
4.
Wireless Networks - With the dynamic voltage scaling (DVS) technology, the terminal node (TN) can dynamically adjust its computational speed, thus providing a new way to save energy during task... 相似文献
5.
Mobile Networks and Applications - Due to fast deployment, strong survivability and flexible scheduling, multiple unmanned aerial vehicles (UAV) can synergistically optimize the trajectory and... 相似文献
6.
Neural Processing Letters - This paper is concerned with topology identification of stochastic multi-weighted complex networks based on adaptive synchronization. Different from previous work,... 相似文献
7.
Donghai Xu Peng Feng Yang Wang Wanpeng Yang Yu Wang Shaoyan Sun 《American Institute of Chemical Engineers》2022,68(2):e17472
Corrosion and salt deposition problems severely restrict the industrialization of supercritical water oxidation. Transpiring wall reactor can effectively weaken these two problems by a protective water film. In this work, methanol was selected as organic matter, and the influences of vital structural parameters on water film properties and organic matter removal were studied via numerical simulation. The results indicate that higher than 99% of methanol conversion could be obtained and hardly affected by transpiration water layer, transpiring wall porosity and inner diameter. Increasing layer and porosity reduced reactor center temperature, but inner diameter's influence was lower relatively. Water film temperature reduced but coverage rate raised as layer, porosity, and inner diameter increased. Notably, the whole reactor was in supercritical state and coverage rate was only approximately 85% in the case of one layer. Increasing reactor length affected slightly the volume of the upper supercritical zone but enlarged the subcritical zone. 相似文献
8.
9.
Mengwei Liu Jin Zhao Shunzo Shimai Dan Han Jian Zhang Shiwei Wang 《Journal of the American Ceramic Society》2022,105(7):4632-4638
MgAl2O4 transparent ceramics were shaped by a commonly used polyacrylic acid (PAA), which acted as both dispersant and gelling agent. The spinel slurries were prepared by ball-milling MgAl2O4 powder, PAA, and water in an attrition mill. The gelling of slurries happened at room temperature in air atmosphere without any other organic additive. The gelling mechanism was the formation of chelates between Mg2+ and carboxyl groups (-COO−) of PAA. The frequency-based testing method was applied to investigate the gelling process of the as-prepared slurry. In addition, a novel in situ characterization method based on a modified indentation testing was invented to better understand the strengthening of the wet green body with time and to guide when demolding could be carried out. After sintering, transparent MgAl2O4 ceramics with high in-line transmittance were resulted. 相似文献
10.
Xiehuan Li Dan Ye 《International Journal of Adaptive Control and Signal Processing》2022,36(1):104-121
In this article, the memory-based dynamic event-triggered controller design issue is investigated for networked interval type-2 (IT2) fuzzy systems under non-periodic denial-of-service (DoS) attacks. For saving limited network bandwidth, a novel memory-based dynamic event-triggered mechanism (DETM) is proposed to schedule data communication. Unlike existing event-triggered generators, the developed memory-based DETM can utilize a series of newly released signals and further save network resources by introducing interval dynamic variables. Moreover, to improve design flexibility, an IT2 fuzzy controller with freely selectable fuzzy rule number and premise membership functions (MFs) is synthesized. Then, a new switched time-delay system with imperfectly matched MFs is established under the consideration of memory-based DETM and DoS attacks simultaneously. Besides, based on the property of MFs, the boundary information of membership grades and slack matrices are introduced in the stability analysis. Furthermore, by using a piecewise Lyapunov–Krasovskii method, membership-functions-dependent criteria are deduced to ensure the asymptotic stability of built fuzzy switched systems. Finally, the effectiveness of proposed control strategies is demonstrated by simulation examples. 相似文献