全文获取类型
收费全文 | 8218篇 |
免费 | 528篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 127篇 |
综合类 | 28篇 |
化学工业 | 1755篇 |
金属工艺 | 187篇 |
机械仪表 | 189篇 |
建筑科学 | 451篇 |
矿业工程 | 37篇 |
能源动力 | 105篇 |
轻工业 | 1298篇 |
水利工程 | 41篇 |
石油天然气 | 13篇 |
无线电 | 624篇 |
一般工业技术 | 2398篇 |
冶金工业 | 172篇 |
原子能技术 | 68篇 |
自动化技术 | 1255篇 |
出版年
2023年 | 118篇 |
2022年 | 73篇 |
2021年 | 197篇 |
2020年 | 137篇 |
2019年 | 137篇 |
2018年 | 307篇 |
2017年 | 314篇 |
2016年 | 354篇 |
2015年 | 260篇 |
2014年 | 336篇 |
2013年 | 618篇 |
2012年 | 419篇 |
2011年 | 494篇 |
2010年 | 410篇 |
2009年 | 415篇 |
2008年 | 469篇 |
2007年 | 433篇 |
2006年 | 311篇 |
2005年 | 253篇 |
2004年 | 202篇 |
2003年 | 219篇 |
2002年 | 187篇 |
2001年 | 172篇 |
2000年 | 135篇 |
1999年 | 112篇 |
1998年 | 97篇 |
1997年 | 96篇 |
1996年 | 92篇 |
1995年 | 52篇 |
1994年 | 64篇 |
1993年 | 49篇 |
1992年 | 39篇 |
1991年 | 49篇 |
1990年 | 30篇 |
1989年 | 33篇 |
1988年 | 27篇 |
1987年 | 29篇 |
1986年 | 43篇 |
1985年 | 99篇 |
1984年 | 64篇 |
1983年 | 48篇 |
1982年 | 46篇 |
1981年 | 37篇 |
1980年 | 45篇 |
1979年 | 33篇 |
1978年 | 38篇 |
1974年 | 23篇 |
1973年 | 28篇 |
1943年 | 26篇 |
1925年 | 23篇 |
排序方式: 共有8748条查询结果,搜索用时 15 毫秒
21.
Summary ESCA is used to characterize ion beam irradiated P(p-ClPhMA)-samples. The results show a chlorine abstraction. The experimental
findings are in accordance with a recently proposed model for a crosslinking mechanism of halogenated aromatic polymers. 相似文献
22.
The next generation of video tapes will use evaporated thin films with their superior properties such as recording density, output level, frequency characteristics and signal-to-noise ratio. This paper describes the metal layer formation by a simple model for the growth of microcolumns at oblique incidence deposition. The most relevant process parameters are discussed. The layout of a production coater is described. 相似文献
23.
D. Y. C. Lie A. Vantomme F. Eisen T. Vreeland M. -A. Nicolet T. K. Carns K. L. Wang B. Holländer 《Journal of Electronic Materials》1994,23(4):369-373
We compare both the strain and damage that 100 keV Si irradiation at room temperature introduces in pseudomorphic and relaxed
GexSi1−x films grown on Si(100) substrates. The ion range is such that the Si/GexSi1−x interface is not significantly damaged. The amount of damage produced in pseudomorphic and relaxed GexSi1−x layers of similar x for irradiation doses up to 2.5 × 1014 Si/cm2 is the same, which proves that a pre-existing uniform strain does not noticeably affect the irradiation-induced damage. However,
the irradiation-induced strain does depend on the pre-existing strain of the samples. Possible interpretations are discussed.
On leave from Inst. voor Kern en Stralingsfysika, Catholic University of Leuven, Belgium. 相似文献
24.
This paper presents work directed at capturing the entrepreneurial and collaborative activity of university researchers. The Triple Helix points to the emergence of the entrepreneurial university as well as to an increasing overlay of activities in universities, industry and government. This study explores ways in which patent-based metrics could be utilized in a Triple Helix context, and how hybrid indicators could be developed by combining patent with survey data. More specifically, it aims to develop indicators that connect technological inventiveness of university researchers to both funding organizations and users, as well as to entrepreneurial activities by academics. The paper develops a simplified model of the innovation process to benchmark the relevance of the indicators to the Triple Helix. An analysis of Finnish academic patents illustrates that patent data can already provide useful indicators but, on its own, cannot provide information about how academic patents are interconnected with government or industry through funding or utilization links. An exclusive analysis of patents can point to patent concentrations on certain universities, to inventors and assignees, or to potential gaps in translating applied science into industrial technology. However, the patent data had to be combined with an inventor survey in order to relate academic patents more to their Triple Helix environment. The survey indicated that most patented academic inventions are connected to (often publicly funded) scientific research by the inventors and tend to be utilized in large firms rather than in start-up companies founded by academic entrepreneurs. 相似文献
25.
Droplet formation on Si surfaces bombarded by 10 keV beams from a liquid metal indium ion source has been observed. It has been verified that excess indium is transported in the ion beam, probably in the form of charged droplets. SIMS, SEM and RBS techniques have been used to study the distribution of droplets at the surface. At the specified ion source operating conditions, equilibrium droplet coverage is of the order of 25%. Individual droplets have an average diameter of 0.35 ωm and an average height of 2.2 nm. At a bombardment current density of 0.1 mA cm?2, equilibrium coverage is reached in about 1 s. 相似文献
26.
27.
28.
Wan-Yu Wu Jyh-Ming Ting Hayo Zutz Dominika Lyzwa Inga Gerhards Carsten Ronning Hans Hofsäss 《Diamond and Related Materials》2008,17(7-10):1494-1497
While experimenting with the growth of metal-containing amorphous carbon (a-c:Me) thin films using two different growth processes, self-assembled multilayered structures were observed. One of the processes is a reactive magnetron sputter deposition process. The other process is a mass selective ion beam deposition process. Despite of the differences in the growth method and the growth condition, self-assembled multilayered thin films, consisting of alternating dark layer and bright layer, were obtained in both processes. Based on the consideration of energy for atomic diffusion in the thin films, the growth mechanism is discussed. 相似文献
29.
30.