全文获取类型
收费全文 | 1866篇 |
免费 | 183篇 |
国内免费 | 57篇 |
专业分类
电工技术 | 69篇 |
综合类 | 63篇 |
化学工业 | 465篇 |
金属工艺 | 92篇 |
机械仪表 | 112篇 |
建筑科学 | 82篇 |
矿业工程 | 21篇 |
能源动力 | 58篇 |
轻工业 | 162篇 |
水利工程 | 23篇 |
石油天然气 | 27篇 |
武器工业 | 9篇 |
无线电 | 167篇 |
一般工业技术 | 349篇 |
冶金工业 | 45篇 |
原子能技术 | 12篇 |
自动化技术 | 350篇 |
出版年
2024年 | 5篇 |
2023年 | 26篇 |
2022年 | 28篇 |
2021年 | 70篇 |
2020年 | 45篇 |
2019年 | 53篇 |
2018年 | 101篇 |
2017年 | 87篇 |
2016年 | 103篇 |
2015年 | 86篇 |
2014年 | 93篇 |
2013年 | 166篇 |
2012年 | 103篇 |
2011年 | 135篇 |
2010年 | 135篇 |
2009年 | 116篇 |
2008年 | 102篇 |
2007年 | 75篇 |
2006年 | 66篇 |
2005年 | 32篇 |
2004年 | 20篇 |
2003年 | 37篇 |
2002年 | 50篇 |
2001年 | 46篇 |
2000年 | 39篇 |
1999年 | 28篇 |
1998年 | 23篇 |
1997年 | 16篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 14篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1973年 | 5篇 |
排序方式: 共有2106条查询结果,搜索用时 17 毫秒
1.
2.
3.
Journal of Mechanical Science and Technology - The idea of integral calculus is used in traditional milling force prediction methods. In the traditional method, the milling cutter is divided into... 相似文献
4.
Pavel Strunz Debashis Mukherji Přemysl Beran Ralph Gilles Lukas Karge Michael Hofmann Markus Hoelzel Joachim Rösler Gergely Farkas 《Metals and Materials International》2018,24(5):934-944
An addition of boron largely increases the ductility in polycrystalline high-temperature Co–Re alloys. Therefore, the effect of boron on the alloy structural characteristics is of high importance for the stability of the matrix at operational temperatures. Volume fractions of ε (hexagonal close-packed—hcp), γ (face-centered cubic—fcc) and σ (Cr2Re3 type) phases were measured at ambient and high temperatures (up to 1500 °C) for a boron-containing Co–17Re–23Cr alloy using neutron diffraction. The matrix phase undergoes an allotropic transformation from ε to γ structure at high temperatures, similar to pure cobalt and to the previously investigated, more complex Co–17Re–23Cr–1.2Ta–2.6C alloy. It was determined in this study that the transformation temperature depends on the boron content (0–1000 wt. ppm). Nevertheless, the transformation temperature did not change monotonically with the increase in the boron content but reached a minimum at approximately 200 ppm of boron. A probable reason is the interplay between the amount of boron in the matrix and the amount of σ phase, which binds hcp-stabilizing elements (Cr and Re). Moreover, borides were identified in alloys with high boron content. 相似文献
5.
Changwei Dun Guoxi Xi Ye Zhang Tingting Zhao Yumin Liu Xiaoying Heng Lu Yao 《Ceramics International》2018,44(17):20984-20991
In this study, we investigated the effects of substituting Li+ for Co2+ at the B sites of the spinel lattice on the structural, magnetic and magnetostrictive properties of cobalt ferrites. The Li+ substituted cobalt ferrites, Co1-xLixFe2O4, with x varying from 0 to 0.7 in 0.1 increments, were synthesized with a sol-gel auto-combustion method using the cathode materials of spent Li-ion batteries. X-ray diffraction analysis revealed that all the Co1-xLixFe2O4 nanopowders had a single-phase spinel structure and the lattice parameters decreased with increasing Li+ content, which can be proved by slight shifts towards higher diffraction angle values of the (311) peak. Field emission scanning electron microscopy was used to observe the fractured inner surface of the sintered cylindrical rods and the increased porosity resulted in a decreased magnetostriction. The oxidation states of Co and Fe in the cobalt ferrite samples were examined by X-ray photoelectron spectroscopy. High resolution transmission electron microscopy micrographs showed that most particles were roughly spherical and with sizes of 25–35?nm. Li+ substitution had a strong effect on the saturation magnetization and coercivity, which were characterized with a vibrating sample magnetometer. The Curie temperature was reduced due to the decrease in magnetic cations and the weakening of the exchange interactions. The magnetostrictive properties were influenced by the incorporation of Li+ at the B sites of the spinel structure and correlated with the changes in porosity, magnetocrystalline anisotropy and the cation distribution. 相似文献
6.
7.
Bedich ika Helena Bendov Ivan Macha
《Chemical Engineering and Processing: Process Intensification》2005,44(12):1312-1319
A procedure has been proposed for the estimation of the terminal falling velocity of non-spherical particles moving in a Carreau model fluid in the transition flow region. The procedure is based on a modification of the relationship formerly developed for the fall of spherical particles including the particle dynamic shape factor. The suitability of the proposed procedure has been confirmed by good agreement between experimental and calculated terminal falling velocity data. In the experiments, the terminal falling velocity of short cylinders and rectangular prisms in polymer solutions of different measure of shear thinning and elasticity has been measured. 相似文献
8.
9.
10.
概括介绍了现代公共建筑中餐饮废水的水质特点及处理要求,并结合公共建筑餐饮废水处理工艺的特殊性,对混凝法、生物法、电化学法等一些处理工艺及工程应用实例进行了综述.认为具备一体化、体积小、占地少、噪音低、处理效果好、运行管理方便等特点的新型餐饮废水处理技术将得到广泛的应用. 相似文献