全文获取类型
收费全文 | 1000篇 |
免费 | 100篇 |
国内免费 | 97篇 |
专业分类
电工技术 | 7篇 |
综合类 | 63篇 |
化学工业 | 127篇 |
金属工艺 | 94篇 |
机械仪表 | 44篇 |
建筑科学 | 5篇 |
矿业工程 | 3篇 |
能源动力 | 8篇 |
轻工业 | 16篇 |
水利工程 | 1篇 |
石油天然气 | 6篇 |
武器工业 | 4篇 |
无线电 | 265篇 |
一般工业技术 | 91篇 |
冶金工业 | 60篇 |
原子能技术 | 24篇 |
自动化技术 | 379篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 12篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 22篇 |
2016年 | 15篇 |
2015年 | 21篇 |
2014年 | 56篇 |
2013年 | 79篇 |
2012年 | 66篇 |
2011年 | 80篇 |
2010年 | 69篇 |
2009年 | 89篇 |
2008年 | 78篇 |
2007年 | 94篇 |
2006年 | 87篇 |
2005年 | 61篇 |
2004年 | 47篇 |
2003年 | 49篇 |
2002年 | 44篇 |
2001年 | 35篇 |
2000年 | 28篇 |
1999年 | 20篇 |
1998年 | 10篇 |
1997年 | 17篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 1篇 |
排序方式: 共有1197条查询结果,搜索用时 15 毫秒
1.
A. Gangopadhyay Z. Liu S. J. Simko S. L. Peczonczyk J. B. Cuthbert E. D. Hock 《摩擦学汇刊》2018,61(4):621-631
Polyalkylene glycols (PAG) have been explored as a possible base stock for engine oil formulation. The friction, wear, and load-carrying capacity of five different PAG chemistries were evaluated either as a base stock or as formulated oils in pure sliding and sliding-rolling conditions using various laboratory bench test rigs operating under boundary and mixed lubrication regimes. The results were compared against GF-5 SAE 5W-20 and a mineral-based oil. The wear surfaces were also characterized using various surface-sensitive techniques for analysis of tribofilms to understand the mechanism of friction reduction. The results indicated that PAG oils show lower friction/traction coefficients and improved load-carrying capability, depending on the formulation, than those of the GF-5 SAE 5W-20 and mineral-based oil. The adsorption of PAG molecules on the surface appeared to be responsible for the lower friction characteristics. 相似文献
2.
3.
4.
Integral cryptanalysis, which is based on the existence of (higher‐order) integral distinguishers, is a powerful cryptographic method that can be used to evaluate the security of modern block ciphers. In this paper, we focus on substitution‐permutation network (SPN) ciphers and propose a criterion to characterize how an r‐round integral distinguisher can be extended to an (r+1)‐round higher‐order integral distinguisher. This criterion, which builds a link between integrals and higher‐order integrals of SPN ciphers, is in fact based on the theory of direct decomposition of a linear space defined by the linear mapping of the cipher. It can be directly utilized to unify the procedure for finding 4‐round higher‐order integral distinguishers of AES and ARIA and can be further extended to analyze higher‐order integral distinguishers of various block cipher structures. We hope that the criterion presented in this paper will benefit the cryptanalysts and may thus lead to better cryptanalytic results. 相似文献
5.
研究了常规AE_2S和窄分布AE_2S的理化性能,并对其在餐具洗涤剂和洗衣液等产品中的去污力、泡沫和黏度等应用性能进行了研究。结果表明,窄分布AE_2S具有较高的临界胶束浓度(cmc),表面张力(γ_(cmc))与常规AE_2S相近,但其钙皂分散、抗硬水性能优于常规AE_2S;在餐具洗涤剂配方中,窄分布AE_2S体系的去油率、泡沫和增黏性能优于常规AE_2S;在普通洗衣液和皂基洗衣液配方中,窄分布AE_2S体系对炭黑、蛋白和皮脂污布的综合去污力与常规AE_2S相当,增黏性和泡沫高于常规AE_2S。 相似文献
6.
7.
Wen Cao Changqing Cao Liejin Guo Hui Jin Matthew Dargusch Debra Bernhardt Xiangdong Yao 《International Journal of Hydrogen Energy》2017,42(15):9448-9457
The potential of diosgenin solid waste (DSW) to be a proper feedstock for hydrogen production from supercritical water gasification was assessed through thermodynamic analysis and experimental study. The thermodynamic analysis of DSW gasification in SCW was performed by Aspen Plus software based on the principle of minimum Gibbs free energy. The effects of temperature (500–650 °C), flow ratio of feedstock slurry to preheated water on the gasification were studied. K2CO3 and black liquor were used to catalyze the gasification of DSW. The morphological structures of DSW and residue char were characterized by SEM. The results showed that DSW was almost completely gasified at 650 °C without catalyst and the carbon gasification efficiency reached up to 98.55%. K2CO3 could significantly promote the gasification reactivity of DSW at a lower temperature. H2 yield was remarkably improved by adding black liquor. The SEM analysis indicated that parts of the organic matters reacted to form gases and liquid products, and K2CO3 was found to migrate into the residue char during the reactions. 相似文献
8.
近几年图形处理器GPU的通用计算能力发展迅速,现在已经发展成为具有巨大并行运算能力的多核处理器,而CUDA架构的推出突破了传统GPU开发方式的束缚,把GPU巨大的通用计算能力解放了出来.本文利用GPU来加速AES算法,即利用GPU作为CPU的协处理器,将AES算法在GPU上实现,以提高计算的吞吐量.最后在GPU和CPU... 相似文献
9.
针对AES和CLEFIA的改进Cache踪迹驱动攻击 总被引:1,自引:0,他引:1
通过分析"Cache失效"踪迹信息和S盒在Cache中不对齐分布特性,提出了一种改进的AES和CLEFIA踪迹驱动攻击方法。现有攻击大都假定S盒在Cache中对齐分布,针对AES和CLEFIA的第1轮踪迹驱动攻击均不能在有限搜索复杂度内获取第1轮扩展密钥。研究表明,在大多数情况下,S盒在Cache中的分布是不对齐的,通过采集加密中的"Cache失效"踪迹信息,200和50个样本分别经AES第1轮和最后1轮分析可将128bit AES主密钥搜索空间降低到216和1,80个样本经CLEFIA第1轮分析可将128bit CLEFIA第1轮扩展密钥搜索空间降低到216,220个样本经前3轮分析可将128bit CLEFIA主密钥搜索空间降低到216,耗时不超过1s。 相似文献
10.
将差分功耗分析的汉明重量模型与传统的代数攻击相结合,实现了针对128位密钥的AES密码算法第一轮的功耗代数攻击.在攻击实验中,改进了汉明重量函数,并证明了利用此函数能够通过进一步计算的相关系数r明显区分出正确密钥字节与错误密钥字节,在最短时间内获得正确的真实的全部密钥字节,对比其他同类研究更具适用性和高效性. 相似文献