全文获取类型
收费全文 | 1025篇 |
免费 | 28篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 71篇 |
综合类 | 5篇 |
化学工业 | 240篇 |
金属工艺 | 24篇 |
机械仪表 | 44篇 |
建筑科学 | 14篇 |
能源动力 | 89篇 |
轻工业 | 82篇 |
无线电 | 80篇 |
一般工业技术 | 193篇 |
冶金工业 | 60篇 |
原子能技术 | 45篇 |
自动化技术 | 107篇 |
出版年
2023年 | 5篇 |
2022年 | 14篇 |
2021年 | 15篇 |
2020年 | 12篇 |
2019年 | 8篇 |
2018年 | 15篇 |
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 17篇 |
2014年 | 25篇 |
2013年 | 57篇 |
2012年 | 35篇 |
2011年 | 59篇 |
2010年 | 45篇 |
2009年 | 55篇 |
2008年 | 64篇 |
2007年 | 53篇 |
2006年 | 34篇 |
2005年 | 47篇 |
2004年 | 49篇 |
2003年 | 43篇 |
2002年 | 27篇 |
2001年 | 29篇 |
2000年 | 23篇 |
1999年 | 26篇 |
1998年 | 27篇 |
1997年 | 28篇 |
1996年 | 27篇 |
1995年 | 20篇 |
1994年 | 15篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 3篇 |
1989年 | 8篇 |
1988年 | 14篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1968年 | 1篇 |
排序方式: 共有1054条查询结果,搜索用时 15 毫秒
91.
Norihito Mayama Hiroyuki Yoshida Tatsuo Iwata Kaoru Sasakawa Atsushi Suzuki Yuya Hanaoka Yoshihiro Morita Akito Kuroda Masanori Owari 《Diamond and Related Materials》2010,19(7-9):946-949
In this study, we report the characterization of carbonaceous films deposited on metal substrates by liquid-phase electrodeposition in methanol. The characterization of carbonaceous films by electrodeposition was examined by means of Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS), secondary ion mass spectrometry (SIMS), atom probe (AP) and high resolution-elastic recoil detection analysis (HR-ERDA). From these results, it was found that the films deposited on the metal substrates were composed of the sp2 and sp3 carbon contents, of which the ratio was about 7:3. Furthermore, the films by electrodeposition contained much hydrogen. The hydrogen contents in the surface were about 60 at.% and those in the subsurface were a few 10 at.%. 相似文献
92.
93.
Takashi Ogihara Nobuyasu Mizutani Masanori Kato 《Journal of the American Ceramic Society》1989,72(3):421-426
Monodispersed ZrO2 seed particles which were prepared by hydrolysis of zirconium alkoxide solutions were allowed to grow by further addition of zirconium alkoxide and water under conditions in which new particles do not nucleate and grow. The particle growth mechanism is presumed to be a surface reaction in which the rate-determining step is a first-order polynuclearlayer growth mechanism. With this method of powder preparation, it is possible to precisely control the particle size, and it may be useful for applications in ceramic processing. 相似文献
94.
CARBON-BASED MATERIALS have been regardedas one of the most important materials in nano-technology.Not only nanotubes and fullerenes but alsoa new form of carbon incorporating distinct graphiticconfigurations in amorphous carbon networks hasrecently attracted extensive interests in order toaccomplish high performances by combining diversephysical properties which arise from carbon structuresfl,2].In particular,the establishment of functionallyhybridized carbon systems with a thin film f… 相似文献
95.
Masahiro Fujimoto Mamoru Ishida Akihiko Fujii Yoshimine Sakamoto Norifumi Fujita Seiji Shinkai Masanori Ozaki 《Synthetic Metals》2009,159(9-10):871-874
The molecular alignment of polydiacetylene (PDA) derivatives and their optical and electrical properties of thin films based on PDA derivatives have been studied. The PDA derivatives were aligned depending on the direction of applied shear stress in the film. From measurements of the polarized absorption and current–voltage characteristics, the optical and electrical anisotropies have been observed, that was discussed by taking the PDA main chain alignment into consideration. 相似文献
96.
97.
NiInGe ohmic contact materials, which are attractive to use in future GaAs devices, were previously developed in our laboratories.
Although the NiInGe contacts provided low contact resistances of about 0.3 Ω-mm and excellent thermal stability, further reduction
of the contact resistance (RC) of the NiInGe contacts was mandatory to use these contacts in submicron devices. In this paper, the microstructural parameters,
which influence the RC values, were investigated by correlating the RC values with the microstructure at the interface between the contact materials and the GaAs substrate. The RC values of the NiInGe contacts were found to depend strongly on the volume fraction and the In concentration (x) of the InxGa1−xAs compound semiconductor layers, which were formed at the metal/GaAs interface. Both the volume fraction and the In concentration
of the InxGa1−xAs layers were found to depend on the thickness of the In layer used in the NiInGe contact and the annealing temperature to
form the ohmic contact. A RC value of 0.18 Ω-mm was obtained for the Ni (18 nm)/In (13 nm)/Ge (30 nm) contact (where a slash “/” indicates the deposition
sequence) after annealing at temperature of 650°C for 5 sec. 相似文献
98.
The entropy and the mutual entropy for states and channels are totally studied in general quantum systems described byC*-algebras. In particular, we discuss the relations among theS-entropy and the mutual entropy introduced by Ohya and the Connes-Narnhofer-Thirring entropy. 相似文献
99.
100.
Any solution for an inverse heat conduction problem makes the estimation of surface temperature and surface heat flux worsen in the case where these values behave like a triangular shape change with time. In order to compensate for this defect, Monde and colleagues, who succeeded in obtaining analytical inverse solutions using the Laplace transform technique, introduce a new idea where these changes over the entire measurement time can be split into several parts depending on the behavior. Therefore, an approximate equation to trace the measured temperature change can be derived, resulting in good estimation of surface temperature and surface heat flux even in the case of the triangular shape change and sharp change. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(7): 630–638, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10117 相似文献