全文获取类型
收费全文 | 3766篇 |
免费 | 263篇 |
国内免费 | 185篇 |
专业分类
电工技术 | 150篇 |
技术理论 | 1篇 |
综合类 | 173篇 |
化学工业 | 611篇 |
金属工艺 | 173篇 |
机械仪表 | 202篇 |
建筑科学 | 308篇 |
矿业工程 | 107篇 |
能源动力 | 115篇 |
轻工业 | 208篇 |
水利工程 | 56篇 |
石油天然气 | 218篇 |
武器工业 | 17篇 |
无线电 | 466篇 |
一般工业技术 | 431篇 |
冶金工业 | 298篇 |
原子能技术 | 51篇 |
自动化技术 | 629篇 |
出版年
2024年 | 5篇 |
2023年 | 51篇 |
2022年 | 95篇 |
2021年 | 129篇 |
2020年 | 98篇 |
2019年 | 89篇 |
2018年 | 112篇 |
2017年 | 126篇 |
2016年 | 97篇 |
2015年 | 137篇 |
2014年 | 162篇 |
2013年 | 227篇 |
2012年 | 217篇 |
2011年 | 252篇 |
2010年 | 208篇 |
2009年 | 215篇 |
2008年 | 190篇 |
2007年 | 195篇 |
2006年 | 167篇 |
2005年 | 176篇 |
2004年 | 112篇 |
2003年 | 92篇 |
2002年 | 91篇 |
2001年 | 84篇 |
2000年 | 117篇 |
1999年 | 129篇 |
1998年 | 130篇 |
1997年 | 98篇 |
1996年 | 101篇 |
1995年 | 68篇 |
1994年 | 46篇 |
1993年 | 44篇 |
1992年 | 26篇 |
1991年 | 25篇 |
1990年 | 22篇 |
1989年 | 15篇 |
1988年 | 20篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有4214条查询结果,搜索用时 15 毫秒
1.
2.
Jiewei Chen Ting Zhang Jingli Wang Ning Zhang Wei Ji Shuyun Zhou Yang Chai 《Advanced functional materials》2021,31(40):2104192
Charge-based field-effect transistors (FETs) greatly suffer from unavoidable carrier scattering and heat dissipation. Analogous to valley degree of freedom in semiconductors, chiral anomaly current in Weyl/Dirac semimetals is theoretically predicted to be nearly nondissipative over long distances, but still lacks experimental ways to efficiently control its transport. Here, field-effect chirality devices are demonstrated with Dirac semimetal PtSe2, in which its Fermi level is close to the Dirac point in the conduction band owing to intrinsic defects. The chiral anomaly is further corroborated by the planar Hall effect and nonlocal valley transport measurement, which can also be effectively modulated by external fields, showing robust nonlocal valley transport with micrometer diffusion length. Similar to charge-based FETs, the chiral conductivity in PtSe2 devices can be modulated by electrostatic gating with an ON/OFF ratio of more than 103. Basic logic functions in the devices are also demonstrated with electric and magnetic fields as input signals. 相似文献
3.
Yunpeng Zhang Jiaofeng Ye Dongan Qu Haitao Wang Changsheng Chai Libang Feng 《Polymer Engineering and Science》2021,61(9):2257-2266
Micro-damage in materials could be repaired by endowing materials with self-healing performance. Herein, an epoxy resin with excellent self-healing performance grounded on thermo-reversible Diels–Alder dynamic chemical reaction was developed. Results showed that the bending strength and adhesive behavior of epoxy resin were influenced dramatically upon treatment with various temperatures. More importantly, damages created in epoxy resin could be repaired completely after suitable heat treatments. What is more, the healed epoxy resin exhibited much higher bending strength and adhesive performance than the pristine one did. The materials could be damaged and then repaired repeatedly. Meanwhile, the as-prepared self-healing epoxy resin exhibited excellent thermal reversibility and controllable adhesion. The thermo-adjusted self-healing performance endowed epoxy resin with recyclable and reusable performance. Therefore, the research made it possible of recycling waste epoxy resins. 相似文献
4.
Wireless Networks - Nowadays, people trade electricity through centralized companies or organizations which is vulnerable to cyber attacks and incapable of coping with increasing demands from... 相似文献
5.
Catalysis Letters - In this paper, five recombinant strains: GS115-LacA, GS115-LacB, GS115-LacC, KM71H-Lcc1 and GS115-Lcc2 were selected to produce laccase isozymes with high activities, which... 相似文献
7.
现有的压接设备可控性差、操作复杂,导致压接质量因人而异。针对此问题,提出了基于DDVC技术的导线压接设备自动化控制方案,建立了速度控制系统数学模型,应用Simulink进行仿真,分析系统性能。建立了基于DEFORM的耐张线夹压接实验模型,获得了耐张线夹压接的最佳加载速度曲线,并以此作为压接设备速度控制系统的Simulink仿真模型输入,对压接过程进行了仿真分析。结果表明:开环控制时系统存在一定的超调,加入PID控制后可有效抑制超调;所设计的压接设备可很好地跟随最佳压接曲线,跟随误差仅为0. 904 mm·s-1。研究成果对改进压接设备、提高压接质量提供了新的解决方案。 相似文献
8.
9.
Zhuangzhuang Chai Zhengwen Yang Jianbei Qiu Jialun Zhu Zhiguo Song 《Ceramics International》2018,44(12):13757-13764
Metal nanoparticles preparation in the interior of nanoscale skeleton of inverse opals made up of crystallized matrix is more difficult than the preparation of pure inverse opals. In the present work, the Ag or Au nanoparticles embedded YbPO4:Er3+ inverse opals were prepared by a simple approach, which involved the infiltration of opal template by using the transparent YbPO4:Er3+ sol including silver nitrate or chloroauric acid and the sintering at high temperature. The 20–30?nm Au or 5–10?nm Ag nanoparticles were formed in the interior of nanoscale skeleton in the YbPO4:Er3+ inverse opals, and the Ag or Au nanoparticles embedded YbPO4:Er3+ inverse opals were prepared. The influence of Ag or Au nanoparticles on the upconversion photoluminescence of YbPO4:Er3+ inverse opal was studied, and the upconversion luminescence enhancement induced by the Ag or Au nanoparticles was observed. The mechanisms of upconversion luminescence enhancement of YbPO4:Er3+ inverse opals induced by Ag or Au nanoparticles were discussed. The enhancement of upconversion luminescence induced by Ag nanoparticles was attributed to the enhancement of the excitation field, and the enhancement of upconversion emission induced by Au nanoparticles was related to the increasing of the radiation decay rate of Er3+. 相似文献
10.
Junlan Chai 《中国耐火材料》2018,(1)
正Four issues per volume a year,CHINA’S REFRACTORIES is distributed worldwide by airspeed delivery at no extra cost to subscribers. 相似文献