全文获取类型
收费全文 | 13446篇 |
免费 | 1132篇 |
国内免费 | 436篇 |
专业分类
电工技术 | 318篇 |
技术理论 | 1篇 |
综合类 | 1050篇 |
化学工业 | 5210篇 |
金属工艺 | 580篇 |
机械仪表 | 478篇 |
建筑科学 | 1600篇 |
矿业工程 | 658篇 |
能源动力 | 421篇 |
轻工业 | 685篇 |
水利工程 | 400篇 |
石油天然气 | 807篇 |
武器工业 | 30篇 |
无线电 | 346篇 |
一般工业技术 | 721篇 |
冶金工业 | 944篇 |
原子能技术 | 237篇 |
自动化技术 | 528篇 |
出版年
2024年 | 71篇 |
2023年 | 158篇 |
2022年 | 344篇 |
2021年 | 400篇 |
2020年 | 483篇 |
2019年 | 396篇 |
2018年 | 353篇 |
2017年 | 409篇 |
2016年 | 427篇 |
2015年 | 469篇 |
2014年 | 750篇 |
2013年 | 809篇 |
2012年 | 1033篇 |
2011年 | 989篇 |
2010年 | 817篇 |
2009年 | 837篇 |
2008年 | 674篇 |
2007年 | 842篇 |
2006年 | 804篇 |
2005年 | 699篇 |
2004年 | 556篇 |
2003年 | 498篇 |
2002年 | 411篇 |
2001年 | 352篇 |
2000年 | 274篇 |
1999年 | 254篇 |
1998年 | 206篇 |
1997年 | 150篇 |
1996年 | 114篇 |
1995年 | 86篇 |
1994年 | 62篇 |
1993年 | 45篇 |
1992年 | 46篇 |
1991年 | 32篇 |
1990年 | 27篇 |
1989年 | 18篇 |
1988年 | 13篇 |
1987年 | 30篇 |
1986年 | 15篇 |
1985年 | 18篇 |
1984年 | 20篇 |
1983年 | 11篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1976年 | 2篇 |
1965年 | 1篇 |
1962年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
Two zinc-rich powder coatings are applied onto phosphatised steel substrate and are studied using electrochemical impedance spectroscopy (EIS). Measurements are performed before (dry experiment) and during immersion in artificial sea water. Before immersion, EIS spectra show that percolation threshold is not attained for coating A, while coating B presents an effective percolation. In this latter case, and in order to account for the distribution of the zinc particles within the coating described as isolated, semi-isolated and percolant grains, a distributed transmission line model is proposed. When panels are immersed, the model is modified due to the electrolyte penetration through the coating, in particular with the introduction of an ionic resistance. However, it is shown that EIS spectra are not significantly modified when this ionic resistance is changed. 相似文献
93.
94.
96.
97.
The possibility of multiplicity in an isothermal continuous mixed suspension-mixed product removal crystallizer is explored using the bifurcation theory.A process involving agglomeration controlled precipitation is considered in which secondary nucleation occurs simultaneously with primary nucleation.The determinant equations for the existence of multiple steady states are developed and the multiplicity boundaries dependent on the physical and kinetic properties and operational parameters of the process are obtained by resolving these determinant equations.The number of steady states in the precipitator for various multiplicity regions is determined and the linear stability of these steady states is analyzed by using the Routh criterion. 相似文献
98.
《Fuel》2003,82(2):147-151
The aim of this paper is to show how a cheap carbonaceous material such as low rank coal-based carbon (or char) can be used in the combined SO2/NO removal from exhaust gas at the linear gas velocity used in commercial systems (0.12 m s−1). Char is produced from carbonization and optionally activated with steam. This char is used in a first step to abate the SO2 concentration at the following conditions: 100 °C, space velocity of 3600 h−1, 6% O2, 10% H2O, 1000 ppmv SO2, 1000 ppmv NO and N2 as remainder. In a second step, when the SO2 concentration in the flue gas is low, NO is reduced to N2 and steam at the following experimental conditions: 150 °C, space velocity of 900 h−1, 6% O2, 10% H2O, 0-500 ppmv SO2, 1000 ppmv NO, 1000 ppmv NH3 and N2 as remainder.It has been shown that the presence of NO has no effect on SO2 abatement during the first step of combined SO2/NO removal system and that low SO2 inlet concentration has a negligible effect on NO reduction in the second step. Moreover, this char can be thermally regenerated after use for various cycles without loss of activity. On the other hand, this regenerated char shows the highest NO removal activity (compared to parent chars, either carbonized or steam activated) which can be attributed to the activating effect of the sulfuric acid formed during the first step of the combined SO2/NO removal system. 相似文献
99.
电解法处理利福霉素SV钠废渣分离液的研究 总被引:2,自引:0,他引:2
根据电化学原理,采用电解法,利用铁屑与炭粒作电极,处理利福霉素SV钠药渣分离液,讨论各种因素对分离液污染物作效果的影响,COD去除率可达91.8%左右,脱色率可达95%左右。 相似文献
100.
非金属电镀用导电漆的研制 总被引:1,自引:0,他引:1
介绍了导电漆、作为导电填料的片状镀银铜粉的制备工艺流程。分别研究了漆膜表面单位电阻与镀银铜粉的含量及其粒径以及钛酸酯偶联剂的含量之间的关系。结果表明,当镀银铜粉的粒径为400目、质量分数在57%~65%之间,钛酸酯偶联剂的质量分数为10%时,所得涂膜的导电性能最佳。加入含C-18的油酸可以使导电漆长期贮存而电阻值不变。经检测,所得涂膜具有良好的性能:附着力1级,硬度1 H,柔韧性1 mm,冲击强度50 kg/cm2,膜厚10~15μm,漆膜表面每厘米电阻0.15Ω,每分米电阻0.47Ω。指出了导电漆应用过程中的注意事项。 相似文献