全文获取类型
收费全文 | 427篇 |
免费 | 4篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 169篇 |
金属工艺 | 13篇 |
机械仪表 | 10篇 |
建筑科学 | 7篇 |
能源动力 | 17篇 |
轻工业 | 37篇 |
石油天然气 | 1篇 |
无线电 | 34篇 |
一般工业技术 | 76篇 |
冶金工业 | 14篇 |
原子能技术 | 16篇 |
自动化技术 | 34篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 13篇 |
2013年 | 26篇 |
2012年 | 21篇 |
2011年 | 24篇 |
2010年 | 24篇 |
2009年 | 23篇 |
2008年 | 22篇 |
2007年 | 14篇 |
2006年 | 21篇 |
2005年 | 15篇 |
2004年 | 19篇 |
2003年 | 13篇 |
2002年 | 23篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 5篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有431条查询结果,搜索用时 3 毫秒
31.
Fast and Almost Complete Nitridation of Mesoporous Silica MCM-41 with Ammonia in a Plug-Flow Reactor
Fumitaka Hayashi Ken-ichi Ishizu Masakazu Iwamoto 《Journal of the American Ceramic Society》2010,93(1):104-110
The title reaction proceeded well to yield silicon (oxy)nitride at 973–1323 K using a plug-flow reactor. The degree of nitridation was studied as a function of temperature and time of nitridation, the sample weight, and the flow rate of ammonia. It was dependent on the reaction temperature and the amount of ammonia supplied per sample weight. The nitridation at 1273 K for 10–25 h yielded the oxynitride with 36–39 wt% nitrogen, which was very close to 40 wt% of Si3 N4 . Characterization with X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy measurements, and nitrogen adsorption revealed the conversion of MCM-41 to the corresponding oxynitride without essential loss of the mesoporous structure, the decrements of the lattice constant and the pore diameter by 20–35%, and the increments of the wall thickness by ca. 45%. Solid-state 29 Si nuclear magnetic resonance spectra during the nitridation clearly showed fast decrease in SiO4 species and slow in SiO3 (OH). Various intermediate species, SiO x N y (NH2 or NH) z , were observed to be formed and finally, ca. 70% SiN4 species, ca. 20% SiN3 (NH2 or NH), and ca. 10% SiON2 (NH2 or NH) were produced, being consistent with the results of the above mentioned elemental analysis. 相似文献
32.
33.
Ken-ichi Anjyo 《The Visual computer》1991,7(1):1-12
This paper describes a new approach to stochastic modeling for natural objects that provides a unified model for describing terrains, clouds, sea waves and many other shapes. The geometrical data of the model can be created or modified without undue computational time, simply by specifying several parameters. In addition, these parameters have intuitive meanings, which make it easy to control the model's geometry. Then the models for different natural objects can be effectively combined through some functional operations, which makes the method more flexible for acquiring realistic images of complex three-dimensional scenes. 相似文献
34.
35.
Shock compaction experiments for some diamond composites were carried out, and the best consolidated compacts of diamond/SiC and diamond/TiC had relative densities of 95% and 96%, and microhardnesses of 51 ± 2.9 and 48.6 ± 4.8 GPa, respectively. For obtaining better compacts on the shock compaction of mixtures, the ratio of the constituent particle sizes and the properties of the constituent materials are considered, and then the starting conditions of the mixtures must be decided. Here, a simple model concerned with the influence of both the ratio of the constituent particle sizes and the thermal properties of the constituent materials on the shock compaction of mixtures is also presented. 相似文献
36.
Ken-ichi Kurobe Takashi Fuyuki Hiroyuki Matsunami 《Solar Energy Materials & Solar Cells》2001,66(1-4)
High growth-rate Si epitaxy by plasma-enhanced chemical vapor deposition (PECVD) has been investigated for a thin-film solar cell application. A high growth rate of 50 μm/h was obtained at 1050°C with plasma which is 50% larger than that by the conventional CVD without plasma. The electrical properties are almost the same for epitaxial layers with and without plasma. For undoped n-type layers, the Hall mobility and carrier density were about 600 cm2/V s and low 1015 cm−3, respectively. The electron diffusion length in doped p-type layers was about 20 μm. These electrical properties for the layer with plasma, in spite of higher growth rate, are comparable or better than those without plasma. 相似文献
37.
Kitaoka Haru Amano Ken-ichi Nishi Naoya Sakka Tetsuo 《Optimization and Engineering》2022,23(2):1033-1055
Optimization and Engineering - The Nelder-Mead (NM) method is a popular derivative-free optimization algorithm owing to its fast convergence and robustness. However, it is known that the method... 相似文献
38.
39.
Microbial degradation of cyanobacterial cyclic peptides 总被引:1,自引:0,他引:1
Bacterial strain B-9 possesses hydrolytic enzymes capable of degrading microcystins (MCs) and nodularin that are toxic cyclic peptides produced by cyanobacteria. In the present study, the degradation activities of the cell extract of B-9 against non-toxic cyanobacterial cyclic peptides other than the MCs and nodularin were investigated, and the degradation products were analyzed by liquid chromatography/ion trap tandem mass spectrometry (LC/ITMS). It was confirmed that B-9 could also degrade these cyanobacterial cyclic peptides by hydrolysis of their peptide bonds. These results indicated that this bacterium possesses a very unique hydrolytic activity that can degrade structurally different cyclic peptides and that this may be effective for the detoxification of hazardous cyclic peptides. 相似文献
40.
Barium titanium trioxide (BaTiO3) thin films were deposited on fused silica or silicon wafer substrate from barium dipivaloylmethanate (II) (Ba(dpm)2) and titanium tetraisopropoxide (IV) (TTIP) used as precursors in an oxygen microwave plasma. The substrates were dielectrically heated and the substrate temperatures were around 900 K during the film deposition. The deposition was performed for 15 min and the deposits were identified as BaTiO3 by means of X-ray diffraction, X-ray photoelectron spectroscopy, infrared spectroscopy, and ellipsometry. Oxygen and barium atoms and TiO and CO molecules were identified in the plasma. These species would produce higher deposition rates at lower substrate temperatures than those did in the usual thermal metalorganic chemical vapor deposition (MOCVD). The dielectric constant of the BaTiO3 thin film that was directly deposited on the silicon wafer substrate was as low as 101 order of magnitude. Because the deposit reacted with the substrate and an interdiffusional layer was formed, the platinum layer was coated on the silicon wafer substrate in order to prevent the formation of an interdiffusional layer. The dielectric constant then increased to 103 order of magnitude. 相似文献