全文获取类型
收费全文 | 3626篇 |
免费 | 310篇 |
国内免费 | 51篇 |
专业分类
电工技术 | 31篇 |
综合类 | 218篇 |
化学工业 | 791篇 |
金属工艺 | 48篇 |
机械仪表 | 86篇 |
建筑科学 | 166篇 |
矿业工程 | 58篇 |
能源动力 | 71篇 |
轻工业 | 2134篇 |
水利工程 | 47篇 |
石油天然气 | 56篇 |
武器工业 | 15篇 |
无线电 | 49篇 |
一般工业技术 | 92篇 |
冶金工业 | 67篇 |
原子能技术 | 3篇 |
自动化技术 | 55篇 |
出版年
2024年 | 25篇 |
2023年 | 59篇 |
2022年 | 153篇 |
2021年 | 169篇 |
2020年 | 127篇 |
2019年 | 123篇 |
2018年 | 103篇 |
2017年 | 133篇 |
2016年 | 134篇 |
2015年 | 156篇 |
2014年 | 171篇 |
2013年 | 199篇 |
2012年 | 265篇 |
2011年 | 267篇 |
2010年 | 169篇 |
2009年 | 153篇 |
2008年 | 148篇 |
2007年 | 193篇 |
2006年 | 207篇 |
2005年 | 147篇 |
2004年 | 136篇 |
2003年 | 110篇 |
2002年 | 89篇 |
2001年 | 100篇 |
2000年 | 88篇 |
1999年 | 63篇 |
1998年 | 45篇 |
1997年 | 37篇 |
1996年 | 35篇 |
1995年 | 26篇 |
1994年 | 30篇 |
1993年 | 15篇 |
1992年 | 20篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 3篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3987条查询结果,搜索用时 0 毫秒
1.
2.
3.
NUMERICAL ANALYSIS AND EXPERI- MENT OF UNSTEADY THERMAL FIELD OF ROTOR PLATE FOR EDDY CURRENT RETARDER 总被引:3,自引:0,他引:3
LIU Chengye HE Ren 《机械工程学报(英文版)》2008,21(4):71-75
The physical model based on heat transfer theory and virtual boundary method for analyzing unsteady thermal field of rotor plate for eddy current retarder used in automobile is established and boundary conditions are also defined. The finite element governing equation is derived by Galerkin method. The time differential item is discrete based on Galerkin format that is stable at any condition. And a new style of varying time step method is used in iteration process. The thermal field on the rotor plate at the radial and axle directions is analyzed and varying temperature at appointed points on two side-surfaces is measured. The testing and analytical data are uniform approximately. Finite element method can be used for estimating thermal field of the rotor plate at initial design stage of eddy current retarder. 相似文献
4.
5.
Stefan Kasapis 《International Journal of Food Science & Technology》2002,37(4):403-413
The structural properties of mixtures of pectin, oxidized starch and glucose syrup were investigated using small deformation dynamic oscillation. In the absence of added calcium, preparations of low methoxy pectin with glucose syrup formed viscous solutions, which remained crystal-free at subzero temperatures. Samples of oxidized starch and glucose syrup, on the other hand, exhibited solid-like behaviour because of the crystalline nature of the amylose-like helices. Mixtures of the two polysaccharides with the co-solute clearly showed phase inversion from liquid to solid-like behaviour with increasing amounts of starch in the formulation. The transformation was reflected in the textural properties of samples, which varied from thick solutions to firm gels. The viscoelasticity of the system was modified further by the introduction of high methoxy pectin. Preparations of high methoxy pectin and glucose syrup formed rubbery gels whose amorphous nature underwent a glass transition during cooling. 相似文献
6.
7.
Giampiero Sacchetti Paola Pittia Manuela Biserni Gian G. Pinnavaia & Marco D. Rosa 《International Journal of Food Science & Technology》2003,38(2):135-143
Summary Ready‐to‐eat breakfast cereals immersed in milk undergo undesirable changes in texture because of sudden moisture uptake. The textural changes are ascribable to a plasticizing effect of water, which modifies the mechanical strength of products by softening the starch/protein matrix. In this work, some textural parameters of different cereal flakes were derived from the force–displacement curves monitored during 300 s of immersion in milk. Hardness loss, deformability increment and changes in the force–displacement curve profile were calculated and plotted against soaking time. The application of a sugar coating process to a model cereal flake increased the initial product hardness and improved the preservation of the textural parameters during immersion. The Peleg model closely fitted the experimental data, with regression coefficients from 0.967 to 0.999. 相似文献
8.
Kofi E. Aidoo Richard F. Tester Janet E. Morrison & David MacFarlane 《International Journal of Food Science & Technology》1996,31(5):433-438
Composition and microbiological contamination was measured in samples of pre-packed dates purchased from a number of stores and retail outlets in Greater Glasgow. The sugar content of dried pitted dates was c . 74%, about 10% more than reported on those packs where nutritional information was given. Potentially pathogenic bacteria like Escherichia coli, Staphylococcus aureus and Bacillus cereus were identified in some of the samples together with lactic acid bacteria, yeasts and moulds, Aspergillus flavus and A. parasiticus . Fresh dates were the most heavily contaminated of all samples, probably owing to the high moisture content. 相似文献
9.
货运调车场减速顶噪声及治理的探讨 总被引:1,自引:0,他引:1
铁路货物运输枢纽的调车场中,驼峰调车是主要的调车手段,为提高生产效率和确保安全,沿驼峰下滑道布置的减速器(减速闸,减速顶)的噪声是调车场噪声的主要声源之一,本文通过对昆明东站铁路降噪工程的观测试验项目,探讨了减速顶噪声的特性及治理措施。 相似文献
10.
BiologicalEffectsofFlammulinaVelutipesRichinREonChineseKunmingMiceLiangDingbang(梁定邦);CuiDefang(崔德芳);ZhangJintong(张金桐)(Departm... 相似文献