全文获取类型
收费全文 | 9178篇 |
免费 | 440篇 |
国内免费 | 65篇 |
专业分类
电工技术 | 172篇 |
综合类 | 29篇 |
化学工业 | 2259篇 |
金属工艺 | 166篇 |
机械仪表 | 281篇 |
建筑科学 | 352篇 |
矿业工程 | 7篇 |
能源动力 | 570篇 |
轻工业 | 891篇 |
水利工程 | 111篇 |
石油天然气 | 150篇 |
无线电 | 930篇 |
一般工业技术 | 1596篇 |
冶金工业 | 428篇 |
原子能技术 | 99篇 |
自动化技术 | 1642篇 |
出版年
2024年 | 31篇 |
2023年 | 191篇 |
2022年 | 390篇 |
2021年 | 517篇 |
2020年 | 372篇 |
2019年 | 414篇 |
2018年 | 528篇 |
2017年 | 457篇 |
2016年 | 470篇 |
2015年 | 316篇 |
2014年 | 449篇 |
2013年 | 842篇 |
2012年 | 476篇 |
2011年 | 655篇 |
2010年 | 453篇 |
2009年 | 409篇 |
2008年 | 352篇 |
2007年 | 269篇 |
2006年 | 260篇 |
2005年 | 174篇 |
2004年 | 154篇 |
2003年 | 141篇 |
2002年 | 113篇 |
2001年 | 88篇 |
2000年 | 87篇 |
1999年 | 64篇 |
1998年 | 96篇 |
1997年 | 50篇 |
1996年 | 71篇 |
1995年 | 55篇 |
1994年 | 49篇 |
1993年 | 58篇 |
1992年 | 55篇 |
1991年 | 46篇 |
1990年 | 40篇 |
1989年 | 31篇 |
1988年 | 46篇 |
1987年 | 48篇 |
1986年 | 31篇 |
1985年 | 30篇 |
1984年 | 38篇 |
1983年 | 36篇 |
1982年 | 30篇 |
1981年 | 21篇 |
1980年 | 22篇 |
1979年 | 25篇 |
1978年 | 25篇 |
1977年 | 16篇 |
1976年 | 25篇 |
1975年 | 23篇 |
排序方式: 共有9683条查询结果,搜索用时 62 毫秒
1.
Efficacy of Crude and Purified Chitinases (SsChi50) Extracted from Offal Red Scorpion Fish in Biological Control of Chickpea Weevil (Callosobruchus maculatus L.) 下载免费PDF全文
2.
3.
4.
5.
Reducing the complexity of distance measurement methods for circular turbo codes that use structured interleavers 下载免费PDF全文
Youssouf Ould‐Cheikh‐Mouhamedou 《International Journal of Communication Systems》2015,28(9):1572-1579
The knowledge of turbo code's minimum Hamming distance (dmin) and its corresponding codeword multiplicity (Amin) is of a great importance because the error correction capability of a code is strongly tied to the values of dmin and Amin. Unfortunately, the computational complexity associated with the search for dmin and Amin can be very high, especially for a turbo code that has high dmin value. This paper introduces some useful properties of turbo codes that use structured interleavers together with circular encoding. These properties allow for a significant reduction of search space and thus reduce significantly the computational complexity associated with the determination of dmin and Amin values. © 2014 The Authors. International Journal of Communication Systems published by John Wiley & Sons, Ltd. 相似文献
6.
Purification,structural data and biological properties of polysaccharide from Prunus amygdalus gum 下载免费PDF全文
Fatma Bouaziz Mohamed Koubaa Claire Boisset Helbert Fatma Kallel Dorra Driss Imen Kacem Raoudha Ghorbel Semia Ellouz Chaabouni 《International Journal of Food Science & Technology》2015,50(3):578-584
This work demonstrates the efficiency of almond gum polysaccharides (AGPs) as bioactive compounds. AGPs were first extracted using H2O2, in the presence of NaOH, at different times and temperatures. The optimal extraction conditions were 4% H2O2 and 2 N NaOH, for 7 h at 50 °C, leading to an extraction yield of 58.2% (w/w). After a purification step, the retained AGPs were characterised using high‐performance liquid chromatography showing a molecular weight of 99.3 kDa. The monosaccharide composition of AGPs were assessed using gas chromatography–mass spectrometry. AGPs were found to be a complex heteropolysaccharide with a repeating unit mainly composed of galactose, arabinose, xylose, mannose, rhamnose, and glucuronic acid with the respective ratios: 45:26:7:10:1:11. The acidic nature of the polysaccharide is due to the presence of glucuronic acid. Total antioxidant activity, free radical‐scavenging activity and reducing power assay of AGPs were investigated. The obtained results showed high antioxidant activities of AGPs. Furthermore, beyond 60 mg mL?1, AGPs exhibited bacterial growth inhibition for five pathogenic strains: Escherichia coli, Staphylococcus aureus, Enterococcus feacalis, Pseudomonas aeruginosa and Salmonella typhimurium. 相似文献
7.
8.
9.
10.
The performance of a home made MIS–p-Si solar cell was experimentally studied under various gamma irradiation doses (up to 500 Mrad). The effect of radiation dose on the I−V and C−V characteristics was investigated in this work. The obtained results showed that all the output parameters of the cells under investigation were degraded with gamma radiation exposure. In addition, the effects of fabrication conditions (metal thickness and adding of antireflection coating) on the cell output parameters were also investigated. 相似文献