全文获取类型
收费全文 | 502篇 |
免费 | 22篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 115篇 |
金属工艺 | 15篇 |
机械仪表 | 43篇 |
建筑科学 | 16篇 |
矿业工程 | 4篇 |
能源动力 | 9篇 |
轻工业 | 35篇 |
水利工程 | 3篇 |
石油天然气 | 15篇 |
无线电 | 63篇 |
一般工业技术 | 118篇 |
冶金工业 | 40篇 |
原子能技术 | 5篇 |
自动化技术 | 35篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 15篇 |
2019年 | 19篇 |
2018年 | 32篇 |
2017年 | 26篇 |
2016年 | 27篇 |
2015年 | 15篇 |
2014年 | 28篇 |
2013年 | 39篇 |
2012年 | 15篇 |
2011年 | 32篇 |
2010年 | 30篇 |
2009年 | 28篇 |
2008年 | 28篇 |
2007年 | 36篇 |
2006年 | 23篇 |
2005年 | 20篇 |
2004年 | 20篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1991年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1960年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有524条查询结果,搜索用时 15 毫秒
41.
Emel Ozel Hilmi Yurdakul Servet Turan Matteo Ardit Giuseppe Cruciani Michele Dondi 《Journal of the European Ceramic Society》2010,30(16):3319-3329
Cobalt-doped willemite is a promising blue ceramic pigment, but some important aspects concerning crystal structure, optical properties and technological behaviour are still undisclosed. In order to get new insight on these features, willemite pigments (Zn2?xCoxSiO4, 0 < x < 0.3) were synthesized by the ceramic route and characterized from the structural (XRPD with Rietveld refinement), optical (DRS and colorimetry), microstructural (SEM, STEM, TEM, EDX, EELS) and technological (simulation of the ceramic process) viewpoints. The incorporation of cobalt in the willemite lattice, taking preferentially place in the Zn1 tetrahedral site, induces an increase of unit-cell parameters, metal–oxygen distances, and inter-tetrahedral tilting. It causes shifting and enhanced splitting of spin-allowed bands of Co2+ in tetrahedral coordination, implying slight changes of crystal field strength Dq and Racah B parameter, but increasing spin-orbit coupling parameter λ. Willemite pigments impart deep blue hue to ceramic glazes and glassy coatings with a colouring performance better than commercial Co-bearing colorants in the 800–1200 °C range. Detailed SEM-TEM investigation and microanalysis proved that no diffusion phenomena occur at the pigment–glassy coating interface and that willemite pigments are chemically inert during firing at 1050 °C. 相似文献
42.
Tevfik Tozkoparan Emre Ulas Macit Olcer Cavit Arikan Meric Batmaz Aylin Saracoglu Goknur Murat Ozyilmaz Sevgi Kayhan Ebru Soydas Izmir Branch Archives Noyan Sancar Mehmet Yasa Guven Incirlioglu 李璠 《世界建筑》2010,(7):26-31
<正>一座建筑的性能应当如何来衡量?除了通过统治当代建筑舆论的美学、技术以及经济价值来进行描述之外,我们还能够如何来阐释一座建筑,尤其是一座致力于庇护那些渴望展现自己的艺术家的建筑?有人会问成功的表演是如何实现的,表演者是如何进行伪装的、又是如何展现自己的?根据海德格尔的理论,当我们看不到钉子的时候,铁锤的表现才是成功的;钉子本身的出现通常表明出现了问题。 相似文献
43.
44.
Black iron-chromium (Fe-Cr) bearing oxide pigments are generally utilised as effective colourants in a wide variety of applications. However, in the case of their use within ZnO-containing glazes, they yield an undesirable brown colour instead of expected black colour. In order to understand the colour change in this system, we report the use of focused ion beam (FIB) sample preparation technique followed by the use of analytical transmission electron microscopy (TEM) characterisation techniques. According to the results, the formation of a reaction layer between the pigment and glaze was identified with an average composition of Zn0.48Fe0.79Cr1.32O4. Additionally, the valance of Fe was determined as 3+ in the pigment grain, whereas 2+ in the reaction layer and the glaze, respectively. Therefore, it was concluded that the colour change is occurring as result of the valence variation of Fe, the formation of Zn0.48Fe0.79Cr1.32O4 compound and the outward diffusion of Fe into the glaze. 相似文献
45.
Emine Ubay Cokgor Gulsum Emel Zengin Didem Okutman Tas Seda Oktay Clifford Randall Derin Orhon 《Canadian Metallurgical Quarterly》2006,132(1):68-74
This study investigates the potential of primary sludge fermentation for the generation of readily biodegradable substrate. Experimental evaluation indicates that uncontrolled fermentation converted 22% of the initial volatile suspended solids in the sludge into soluble biodegradable chemical oxygen demand (COD). More than 85% of the soluble COD generated was associated with the formation of short chain volatile fatty acids (VFAs). The recoverable fraction of the fermented sludge supernatant may potentially increase the biodegradable COD content of the primary effluent by 5%. The VFA composition predominantly involved acetic and propionic acids as reported in the literature. Due to the high VFA content, activated sludge Model No. 1 could not predict the COD fractionation in the primary sludge; activated sludge Model No. 3 provided a better interpretation of the oxygen uptake profile through initial storage of the VFAs in the sludge. 相似文献
46.
The influence of temperature on the parameters of the band-to-band emission spectrum of a light-emitting diode based on single-crystal silicon was investigated; the unprecedentedly high stability against variations in temperature was observed for both the electroluminescence intensity at the peak of the spectral distribution (I EL m ) and the wavelength corresponding to this peak (λm). The internal quantum efficiency of the light-emitting diode at room temperature is estimated as no lower than 0.1%. The value of I EL m varies by no more than ~10% as the temperature is varied from 120 to 300 K. The value of λm remains virtually constant in the temperature range of 200–300 K. The unprecedentedly high stability of λm is related to interference effects in the oxide film through which the radiation of the light-emitting exits. It is shown that one of the important factors that govern the temperature stability of I EL m is a decrease in the lifetime of the minority charge carriers with decreasing temperature. 相似文献
47.
G. A. Emel’chenko A. N. Gruzintsev A. B. Kulakov É. N. Samarov I. A. Karpov A. N. Red’kin E. E. Yakimov C. Barthou 《Semiconductors》2007,41(2):176-179
The spectra of spontaneous and stimulated emission of ZnO nanorods grown by two low-temperature procedures are studied. Stimulated emission at 385 nm is observed at room temperature in CVD ZnO nanocrystals pumped by the nitrogen laser radiation at the wavelength 337 nm. The threshold pumping power density for lasing exitonic recombination is ~600 kW/cm2. 相似文献
48.
The focus of this article is to develop a surface plasmon resonance (SPR) nanosensor to determine chloramphenicol (CAP) using the molecularly imprinted nanoparticles. The CAP imprinted nanoparticles were prepared by miniemulsion polymerization method. Then, the nanoparticles were attached onto the SPR nanosensor surface via temperature‐controlled evaporation. Surface characterization studies were performed with atomic force microscopy and contact angle measurements. Kinetic studies were performed with CAP solutions in the concentration range of 0.155–6.192 nM. Florphenicol (FLP) and thiamphenicol (TAP) having similar chemical structures to the template (i.e., CAP) were chosen as competitors to determine selectivity of the nanoparticles. Selectivity constants were observed as 8.86 for CAP/TAP and 8.36 for CAP/FLP. The detection limit was calculated as 40 ng/kg honey sample. In the light of these results, it was emphasized that the SPR nanosensor is able to recognize CAP selectively and has a potential for real‐time CAP detection in honey sample. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
49.
50.
Interactions of silicone rubbers designed for electrical engineering applications with aqueous media
L. B. Boinovich A. M. Emel’yanenko A. S. Pashinin 《Protection of Metals and Physical Chemistry of Surfaces》2009,45(1):89-94
Interactions of a number of electrical engineering silicone rubbers with water and aqueous salt, weakly acidic, and weakly basic solutions were studied by measuring contact angles. A mechanism for leakage currents along the surfaces of silicone insulators was proposed. 相似文献