全文获取类型
收费全文 | 76026篇 |
免费 | 5878篇 |
国内免费 | 3340篇 |
专业分类
电工技术 | 4320篇 |
技术理论 | 5篇 |
综合类 | 5754篇 |
化学工业 | 12271篇 |
金属工艺 | 4497篇 |
机械仪表 | 5009篇 |
建筑科学 | 5819篇 |
矿业工程 | 1977篇 |
能源动力 | 1900篇 |
轻工业 | 5626篇 |
水利工程 | 1417篇 |
石油天然气 | 4286篇 |
武器工业 | 629篇 |
无线电 | 8311篇 |
一般工业技术 | 8483篇 |
冶金工业 | 3651篇 |
原子能技术 | 834篇 |
自动化技术 | 10455篇 |
出版年
2024年 | 201篇 |
2023年 | 907篇 |
2022年 | 1734篇 |
2021年 | 2495篇 |
2020年 | 1931篇 |
2019年 | 1607篇 |
2018年 | 1773篇 |
2017年 | 2091篇 |
2016年 | 1981篇 |
2015年 | 2821篇 |
2014年 | 3642篇 |
2013年 | 4557篇 |
2012年 | 4943篇 |
2011年 | 5517篇 |
2010年 | 5162篇 |
2009年 | 4923篇 |
2008年 | 4859篇 |
2007年 | 4756篇 |
2006年 | 4696篇 |
2005年 | 3971篇 |
2004年 | 2833篇 |
2003年 | 2285篇 |
2002年 | 2264篇 |
2001年 | 2001篇 |
2000年 | 1677篇 |
1999年 | 1741篇 |
1998年 | 1366篇 |
1997年 | 1194篇 |
1996年 | 1127篇 |
1995年 | 852篇 |
1994年 | 747篇 |
1993年 | 531篇 |
1992年 | 449篇 |
1991年 | 359篇 |
1990年 | 255篇 |
1989年 | 231篇 |
1988年 | 183篇 |
1987年 | 128篇 |
1986年 | 98篇 |
1985年 | 76篇 |
1984年 | 68篇 |
1983年 | 41篇 |
1982年 | 41篇 |
1981年 | 30篇 |
1980年 | 27篇 |
1979年 | 14篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1973年 | 5篇 |
1970年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
W. Wang J. Dai J. Tang D.-T. Jiang Y. Chen J. Fang J. He W. Zhou L. Spinu 《Journal of Superconductivity》2003,16(1):155-157
Ball-milling method was applied to dissolve Fe into titanium dioxide (TiO2). X-ray diffraction indicated the starting anatase changed to a rutile-type structure with oxygen deficiency after ball milling. Transmission electron microscopy and X-ray absorption experiments were conducted to examine the possible existence of magnetic impurities in the ball-milled powders after they were leached in HCl solutions. Temperature dependence of the resistivity shows semiconducting behavior and the magnetic hysteresis loops at 5 and 300 K exhibit ferromagnetic characteristics. Fe-doped TiO2 films were also prepared by pulsed laser deposition. The magnetic properties of the films are discussed. 相似文献
72.
73.
74.
Kelvin Tang 《世界电子元器件》2006,(3):63-66
本文介绍M16C平台在先进的数字液晶电视技术以及硬件配置和软件算法方面的作用,同时也将讨论其他的LSI。此外,也为电视制造商用于26英寸或以上液晶电视提供主要解决方案。 相似文献
75.
Disciplinary and linguistic considerations for academic Web linking: An exploratory hyperlink mediated study with Mainland China and Taiwan 总被引:4,自引:0,他引:4
The Web has become an important means of academic information exchange and can be used to give new insights into patterns
of informal scholarly communication. This study develops new methods to examine patterns of university Web linking, focusing
on Mainland China and Taiwan, and including language considerations. Multiple exploratory investigations into Web links were
conducted between universities in these two places. Firstly, inlinks were counted to each university Web site from its national
peers using four alternative Web document models. The results were shown to correlate significantly with research productivity
in Taiwan but not in the Mainland, although in the latter case less reliable institutional data could have been the cause.
For Taiwan, this is the first evidence of a scholarly association with academic linking for a non-English speaking region.
It was then ascertained that the same link counts associated more strongly with scientific than social scientific research
productivity in Taiwan. This confirms the general assumption of greater Web use by the hard sciences. We then investigated
Taiwan-Mainland university cross-links, and found that although English is extensively used on the Web, there was no evidence
that it was the language of preference for informal scholarly communication between the two areas.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
76.
77.
Shiao-Shien Chen Tung-Yang Chen Tien-Hao Tang Jin-Lian Su Tzer-Min Shen Jen-Kon Chen 《Electron Devices, IEEE Transactions on》2003,50(7):1683-1689
This paper proposes a novel low-leakage BiCMOS deep-trench (DT) diode in a 0.18-/spl mu/m silicon germanium (SiGe) BiCMOS process. By means of the DT and an n/sup +/ buried layer in the SiGe BiCMOS process, a parasitic vertical p-n-p bipolar transistor with an open-base configuration is formed in the BiCMOS DT diode. Based on the two-dimensional (2-D) simulation and measured results, the BiCMOS DT diode indeed has the lowest substrate leakage current as compared to the conventional p/sup +//n-well diode even at high temperature conditions, which mainly results from the existence of the parasitic open-base bipolar transistor. Considering the applications of the diode string in electrostatic discharge (ESD) protection circuit designs, the BiCMOS DT diode string also provides a good ESD performance. Owing to the characteristics of the low leakage current and high ESD robustness, it is very convenient for circuit designers to use the BiCMOS DT diode string in their IC designs. 相似文献
78.
79.
玻璃微珠的表面化学镀银及红外辐射性能研究 总被引:6,自引:1,他引:5
采用化学镀方法在玻璃微珠表面镀银,考察了预处理条件、反应温度和反应时间等因素对玻璃微珠表面镀银的影响,并通过扫描电镜和X-射线衍射分析仪,对镀银后玻璃微珠的表面形貌和结构进行了观察和表征。将镀银玻璃微珠用于涂料中,考察了玻璃微珠在涂料中的应用及其红外辐射率的变化,探讨了化学镀条件对涂料红外辐射率的影响,结果表明,在控制反应温度和浓度的条件下,可使镀银玻璃微珠的红外辐射率由原来的1.02降为0.70,将其应用于涂料后,涂层的红外辐射率为0.80。 相似文献
80.