全文获取类型
收费全文 | 317篇 |
免费 | 26篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 71篇 |
金属工艺 | 6篇 |
机械仪表 | 8篇 |
能源动力 | 5篇 |
轻工业 | 8篇 |
无线电 | 41篇 |
一般工业技术 | 148篇 |
冶金工业 | 35篇 |
原子能技术 | 1篇 |
自动化技术 | 14篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 13篇 |
2012年 | 20篇 |
2011年 | 26篇 |
2010年 | 18篇 |
2009年 | 25篇 |
2008年 | 15篇 |
2007年 | 16篇 |
2006年 | 10篇 |
2005年 | 28篇 |
2004年 | 16篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 10篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 14篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有343条查询结果,搜索用时 31 毫秒
1.
A Synthetic Transcriptional Activator of Genes Associated with the Retina in Human Dermal Fibroblasts
下载免费PDF全文
![点击此处可从《Chembiochem : a European journal of chemical biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
2.
A simple template‐free high‐temperature evaporation method was developed for the growth of crystalline Si microtubes for the first time. As‐grown Si microtubes were characterized using X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and room‐temperature photoluminescence. The lengths of the Si tubes can reach several hundreds of micrometers; some of them have lengths on the order of millimeters. Each tube has a uniform outer diameter along its entire length, and the typical outer diameter is ≈ 2–3 μm. Most of the tubes have a wall thickness of ≈ 400–500 nm, though a considerable number of them exhibit a very thin wall thickness of ≈ 50 nm. Room‐temperature photoluminescence measurement shows the as‐synthesized Si microtubes have two strong emission peaks centered at ≈ 589 nm and ≈ 617 nm and a weak emission peak centered at ≈ 455 nm. A possible mechanism for the formation of these Si tubes is proposed. We believe that the present discovery of the crystalline Si microtubes will promote further experimental studies on their physical properties and smart applications. 相似文献
3.
4.
D. Golberg P.S. Dorozhkin Y. Bando M. Mitome C.C. Tang 《Diamond and Related Materials》2005,14(11-12):1857
Various multi-walled nanotubes in the B–C–N system are thoroughly investigated using a JEOL-3100FEF high-resolution field emission transmission electron microscope operating at 300 kV and equipped with an in-column built Omega filter. Spatially-resolved B, C and N elemental maps of the nanotubes are constructed. It is realized that a wide variety of tubular arrays composed of B, C and N atoms may exist in the system. Sandwich-like BN-rich and C-rich alternating tubular shells, graphitic C layers inside and outside of pure BN shells induced either by surface contamination, or electron beam irradiation, separation of C-rich and BN-rich tubes and/or BN particles within tubular bunches may take place. One should carefully take these effects into account while analyzing nanotube physical properties, e.g., electrical or optical, rather than simply rely on electron energy loss spectra typically collected from B, C and N containing nanostructures as a whole. Striking dependence of an individual nanotube electrical conductivity on tubular shell chemistry is demonstrated using I–V curve recording in an atomic force microscope. 相似文献
5.
6.
7.
We observed 3 diabetic patients with intolerable dizziness followed by nausea and vomiting immediately after an initial administration of the alpha-glucosidase inhibitor, voglibose. These symptoms did not recur after discontinuation of the drug. Adverse effects as observed in these cases have not been reported previously. Since the 3 patients were relatively old (average age, 72 years old) and had various degrees of micro- and macroangiopathies, these side effects may have been associated with increased micro- and macrocirculatory disturbances in their central nervous systems through alpha-glucosidase inhibition of this agent. 相似文献
8.
The microstructure and indentation response of pressureless-sintered - and -SiC were studied using a high-resolution electron microscope and analytical electron microscopy. The materials were manufactured with boron and carbon as sintering aids. It was found that the overall porosity of the materials was very low but a large number of carbon inclusions were present. X-ray diffraction revealed the fabricated -SiC material was of the same 3C polytype as the initial starting powder; however, electron microscope observations indicated that the material contained a high density of faulting of the -forms. High-resolution imaging of grain boundaries in these materials indicated that the boundaries were very clean, and when they contained an amorphous intergranular film it was at most 0.5 to 1 nm thick. The presence of boron was not detected. Deformation due to identation took several forms. Firstly, radial cracks extending from the corners of the indent suffered little hindrance from the matrix microstructure, such that transgranular fracture was the dominant mode. Secondly, the deformation zone beneath the indentations showed copious lattice microcracks with some preferred orientation during crack formation and propagation. 相似文献
9.
Noboru Hashimoto Yasushi Sawada Takashi Bando Hiroyoshi Yoden Shigehito Deki 《Journal of the American Ceramic Society》1991,74(6):1282-1286
AIN powder was synthesized from aluminum polynuclear complexes. Basic aluminum chloride and basic aluminum lactate were used as the aluminum polynuclear complexes. These starting materials and glucose were dissolved in water and mixed homogeneously. AIN powder was obtained by calcining after drying and precalcining at 800°C under nitrogen gas flow. Then excess carbon was removed by firing in air. Nitridation in the system was investigated and compared with that in the alumina–carbon black system. It was found that in our reaction system nitridation began and proceeded at lower calcination temperatures above 1200°C than in the alumina–carbon black system. Using aluminum polynuclear complexes, AIN was synthesized through the nitridation of γ-alumina and produced in a very fine and sharp particle size distribution. 相似文献
10.
D. P. Gosain T. Shimizu M. Ohmura M. Suzuki T. Bando S. Okano 《Journal of Materials Science》1991,26(12):3271-3274
Composition dependence of properties of Sb2Te3–x
Se
x
in the range 0x<3 were studied using differential thermal analysis and X-ray diffraction. Sb2Te3–x
Se
x
form solid solution for 0<x1.25 and 2.75x<3. A systematic study of crystallization temperature in Sb2Te3–x
Se
x
(0x2.75) thin films prepared by flash evaporation was carried out. In preliminary experiments for some compositions, more than 103 repetitions between amorphous and crystalline states were attained by the application of electric pulses. 相似文献