全文获取类型
收费全文 | 21937篇 |
免费 | 1673篇 |
国内免费 | 781篇 |
专业分类
电工技术 | 1065篇 |
技术理论 | 3篇 |
综合类 | 1369篇 |
化学工业 | 3888篇 |
金属工艺 | 1070篇 |
机械仪表 | 1348篇 |
建筑科学 | 1714篇 |
矿业工程 | 504篇 |
能源动力 | 586篇 |
轻工业 | 1494篇 |
水利工程 | 351篇 |
石油天然气 | 1216篇 |
武器工业 | 159篇 |
无线电 | 2330篇 |
一般工业技术 | 3174篇 |
冶金工业 | 1228篇 |
原子能技术 | 268篇 |
自动化技术 | 2624篇 |
出版年
2024年 | 79篇 |
2023年 | 314篇 |
2022年 | 486篇 |
2021年 | 643篇 |
2020年 | 523篇 |
2019年 | 468篇 |
2018年 | 504篇 |
2017年 | 624篇 |
2016年 | 565篇 |
2015年 | 737篇 |
2014年 | 902篇 |
2013年 | 1164篇 |
2012年 | 1229篇 |
2011年 | 1326篇 |
2010年 | 1126篇 |
2009年 | 1088篇 |
2008年 | 1155篇 |
2007年 | 1120篇 |
2006年 | 1192篇 |
2005年 | 1152篇 |
2004年 | 737篇 |
2003年 | 707篇 |
2002年 | 653篇 |
2001年 | 559篇 |
2000年 | 716篇 |
1999年 | 761篇 |
1998年 | 666篇 |
1997年 | 591篇 |
1996年 | 524篇 |
1995年 | 478篇 |
1994年 | 352篇 |
1993年 | 269篇 |
1992年 | 216篇 |
1991年 | 176篇 |
1990年 | 136篇 |
1989年 | 119篇 |
1988年 | 98篇 |
1987年 | 48篇 |
1986年 | 53篇 |
1985年 | 45篇 |
1984年 | 19篇 |
1983年 | 6篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1980年 | 12篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1970年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Xing Gu Shariar Sabuktagin Ali Teke Daniel Johnstone Hadis Morkoç Bill Nemeth Jeff Nause 《Journal of Materials Science: Materials in Electronics》2004,15(6):373-378
ZnO is a highly efficient photon emitter, and has optical and piezoelectric properties that are attractive for a variety of applications in sensors and potentially optoelectronic devices such as emitters. Due to its identical stacking order and close lattice match to GaN, it is also being developed as a substrate material for GaN epitaxy. However, the surface finish of the ZnO is such that much of the damage induced by sawing and follow up mechanical polishing remains. We developed a thermal treatment method to eliminate surface damage on the 0 face of ZnO (0 0 0 1) to prepare it for epitaxial growth. Atomic force microscopy images of ZnO (0 0 0 1) annealed at 1050 °C for 3 h etc. show that residual scratches from mechanical polishing are removed and atomically flat, terrace-like surfaces are attained. In addition, low-temperature photoluminescence and high-resolution X-ray diffraction measurements have been employed to investigate the effect of annealing on ZnO substrates. 相似文献
92.
通过适当的工艺措施,采用Bridgman法生长了直径为30mm的X射线及γ射线探测器级的Cd.9Zn0.1Te晶锭.测试结果表明:该晶锭结晶质量良好,位错密度低,成分均匀,杂质含量低,红外透过率和电阻率都十分接近本征Cd.9Zn0.1Te的值.并从晶体的生长特性、缺陷和杂质的角度,分析了生长高性能晶体的条件,研究了生长Cdl-xZnxTe晶体的x值与缺陷和杂质浓度之间的关系. 相似文献
93.
94.
95.
Chuxiang Li Jianhua Lu Jun Gu Ming L. Liou 《The Journal of VLSI Signal Processing》2003,33(3):277-285
In this paper, error-resilient schemes are proposed to support robust video transmission for digital terrestrial TV broadcasting (DTTB). In particular, a temporal error concealment incorporated with a low-complexity block-matching is developed, achieving an effective reception of predictive pictures in harsh terrestrial environment. Special algorithms are also designed for isolated I-pictures. Moreover, combined with an intra/inter case prediction, an adaptive error concealment scheme is further contrived to fit for different error conditions. Extensive simulations have been conducted under various DTTB channel conditions, even with a very high packet error rate, to verify the effectiveness of the proposed schemes. 相似文献
96.
97.
98.
Zheng Jiao Minghong Wu Jianzhong Gu Zheng Qin 《IEEE sensors journal》2003,3(4):435-438
Zinc ferrite is a promising sensor material. In this paper, thin films of nanocrystalline zinc ferrite were deposited on alumina substrates by nebulization of a 0.01-M solution of a mixture of ZnCl/sub 2/ and FeCl/sub 3/ in ethanol (Zn:Fe=1:2) followed by pyrolysis and annealing in flowing air. The resulting films were characterized by X-ray diffraction and scanning electron microscopy, and the gas-sensing properties of as-deposited films were also investigated. 相似文献
99.
Sang-Hoon Lee Dae Hwan Kim Kyung Rok Kim Jong Duk Lee Byung-Gook Park Young-Jin Gu Gi-Young Yang Jeong-Taek Kong 《Nanotechnology, IEEE Transactions on》2002,1(4):226-232
A practical model for a single-electron transistor (SET) was developed based on the physical phenomena in realistic Si SETs, and implemented into a conventional circuit simulator. In the proposed model, the SET current calculated by the analytic model is combined with the parasitic MOSFET characteristics, which have been observed in many recently reported SETs formed on Si nanostructures. The SPICE simulation results were compared with the measured characteristics of the Si SETs. In terms of the bias, temperature, and size dependence of the realistic SET characteristics, an extensive comparison leads to good agreement within a reasonable level of accuracy. This result is noticeable in that a single set of model parameters was used, while considering divergent physical phenomena such as the parasitic MOSFET, the Coulomb oscillation phase shift, and the tunneling resistance modulated by the gate bias. When compared to the measured data, the accuracy of the voltage transfer characteristics of a single-electron inverter obtained from the SPICE simulation was within 15%. This new SPICE model can be applied to estimating the realistic performance of a CMOS/SET hybrid circuit or various SET logic architectures. 相似文献
100.
本文简要阐述了可靠性管理的概念,在我所技术质量管理的基础上,从产品立项、设计、设计评审、流片、封装、考核到鉴定使用全过程,对ASIC可靠性管理进行了分析和探讨,强调各部门必须保证工作质量,强化可靠性管理,通过管理把高可靠性注入到产品中去。 相似文献