全文获取类型
收费全文 | 24421篇 |
免费 | 1162篇 |
国内免费 | 1057篇 |
专业分类
电工技术 | 340篇 |
技术理论 | 1篇 |
综合类 | 835篇 |
化学工业 | 6602篇 |
金属工艺 | 2633篇 |
机械仪表 | 691篇 |
建筑科学 | 388篇 |
矿业工程 | 277篇 |
能源动力 | 1716篇 |
轻工业 | 1177篇 |
水利工程 | 385篇 |
石油天然气 | 833篇 |
武器工业 | 79篇 |
无线电 | 2298篇 |
一般工业技术 | 6822篇 |
冶金工业 | 621篇 |
原子能技术 | 455篇 |
自动化技术 | 487篇 |
出版年
2024年 | 31篇 |
2023年 | 353篇 |
2022年 | 444篇 |
2021年 | 619篇 |
2020年 | 663篇 |
2019年 | 665篇 |
2018年 | 569篇 |
2017年 | 714篇 |
2016年 | 651篇 |
2015年 | 641篇 |
2014年 | 1144篇 |
2013年 | 1428篇 |
2012年 | 1408篇 |
2011年 | 2277篇 |
2010年 | 1577篇 |
2009年 | 1635篇 |
2008年 | 1438篇 |
2007年 | 1463篇 |
2006年 | 1338篇 |
2005年 | 1097篇 |
2004年 | 1011篇 |
2003年 | 919篇 |
2002年 | 763篇 |
2001年 | 513篇 |
2000年 | 513篇 |
1999年 | 402篇 |
1998年 | 406篇 |
1997年 | 328篇 |
1996年 | 318篇 |
1995年 | 309篇 |
1994年 | 236篇 |
1993年 | 151篇 |
1992年 | 119篇 |
1991年 | 103篇 |
1990年 | 78篇 |
1989年 | 63篇 |
1988年 | 53篇 |
1987年 | 32篇 |
1986年 | 32篇 |
1985年 | 25篇 |
1984年 | 16篇 |
1983年 | 24篇 |
1982年 | 16篇 |
1981年 | 18篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Zs. T
kei D. Kelleher B. Mebarki T. Mandrekar S. Guggilla K. Maex 《Microelectronic Engineering》2003,70(2-4):358-362
Passivated single damascene copper SiO2 damascene lines were evaluated in combination with TiSiN and Ta(N)/Ta diffusion barriers. Leakage current, breakdown and time-dependent dielectric breakdown properties were investigated on a wafer level basis for temperatures ranging between room temperature and 150 °C. It is found that the leakage performance of the wafers with a TiSiN barrier is better at room temperature, but at 150 °C the performance levels out with Ta(N)/Ta. Time-dependent dielectric breakdown measurements at 150 °C show that the lifetime of the interconnect is higher with the selected Ta(N)/Ta barrier than for TiSiN. 相似文献
32.
33.
34.
A.L. Pan H.G. ZhengZ.P. Yang F.X. Liu Z.J. Ding Y.T. Qian 《Materials Research Bulletin》2003,38(5):789-796
Small Ag particles or clusters dispersed mesoporous SiO2 composite films were prepared by a new method: First the matrix SiO2 films were prepared by sol-gel process combined with the dip-coating technique, then they were soaked in AgNO3 solutions followed by irradiation of γ-ray at room temperature and in ambient pressure. The structures of these films were examined by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and optical absorption spectroscopy. It has been shown that the Ag particles grown within the porous SiO2 films are very small, and they are isolated and dispersed from each other with very narrow size distributions. With increasing the soaking concentration and an additional annealing, an opposite peakshift effect of the surface plasmon resonance (SPR) was observed in the optical absorption measurements. 相似文献
35.
36.
CMP系统技术与市场 总被引:3,自引:1,他引:2
葛劢冲 《电子工业专用设备》2003,32(1):17-24
概述了CMP系统技术的发展历史、发展趋势以及在IC生产中的重要性,介绍了国外CMP设备主要制造厂家的设备型号和性能及CMP设备市场分布和需求,阐述了CMP系统技术的基础研究、关键技术和国内研究概况。 相似文献
37.
使用光强标定的发射光谱(AOES)测量了CHF3/C6H6混合气体的微波电子回旋共振(ECR)放电等离子体中基团的分布状态。实验发现随着CHF3流量的增加,成膜基团CF、CF2、CH等的相对密度增大,而刻蚀基团F的密度也会增加,从而使得a—C:F薄膜的沉积速率降低。同时红外吸收谱(IR)分析表明,在高CHF3流量下沉积的a—C:F薄膜中含有更高的C—F键成分。可见在a—C:F薄膜的制备中CHF3/(CHF3 C6H6)流量比是重要的控制参量。 相似文献
38.
Toshiyuki MasuiTakanobu Chiga Nobuhito Imanaka Gin-ya Adachi 《Materials Research Bulletin》2003,38(1):17-24
Fine particles of a blue emission phosphor Sr2CeO4 have been synthesized using a chemical co-precipitation technique, and the textual and luminescent properties were compared with the one synthesized by the conventional solid-state reaction method. Particle size and distribution of the Sr2CeO4 fine powder prepared by the co-precipitation process were smaller and narrower than those obtained by the samples prepared from the conventional one. The emission intensity of the fine particles was equal to that of the larger particles prepared from the solid-state reaction, on the contrary to the general tendency that emission intensity decrease with particle size reduction. Although no Ce3+ peaks were observed in EPR measurements, X-ray photoelectron spectra of the samples clearly elucidated the existence of Ce3+ only on the surface of Sr2CeO4. 相似文献
39.
Over the last five years, many activities have focused on the unexploited field of carrying out reactions on small scales. Due to the rapid development of new components, this paper deals with recent developments only in a compressed form. An important point is the analysis of possible plant concepts for microreactors and whether these are a sensible option. Due to the enormous difference in size between the microchannels and the fluid periphera of possible components this is not just a technical question. It touches on the microtechnology concept as a whole. The direction in which the field should be developed and which measures can be taken to influence its development are questions that are addressed here with respect to the big industrial interest in microreactors. 相似文献
40.
Ultra thin (5 nm) silicon oxynitride (SiON) films were fabricated at a low temperature using nitrogen plasma generated by an inductively coupled plasma system. Effects of post-metalization annealing (PMA) of Al/SiON/Si MOS structure on the electrical properties of the SiON films were studied and correlations between the charge trapping states and the leakage current were established. Positive charge trapping by interface states generated by plasma damage was characterized by the hysteresis in high-frequency capacitance-voltage (C-V) characteristics. Hysteresis was observed to be completely removed by PMA while interface state density at the Si mid band gap reduced from 2.2×1013 to 3.7×1011/eV/cm2 and the oxide fixed charge density changed from 3.3×1012 to −4×1011/cm2. The leakage current also decreased significantly, by more than two orders of magnitude, with PMA. The analysis of the leakage current using trap assisted tunneling (TAT) mechanism indicated that with PMA, the trap energy level in the SiON film becomes shallower from 1.3 to 0.7 eV. The positive trapped charges were observed to be annihilated by PMA and the trapping sites became neutral trap centers in the SiON film. This could lead to the reduction in the leakage current component given rise to by TAT. 相似文献