全文获取类型
收费全文 | 166376篇 |
免费 | 12316篇 |
国内免费 | 6097篇 |
专业分类
电工技术 | 8709篇 |
技术理论 | 9篇 |
综合类 | 8732篇 |
化学工业 | 27278篇 |
金属工艺 | 9981篇 |
机械仪表 | 10057篇 |
建筑科学 | 9809篇 |
矿业工程 | 3935篇 |
能源动力 | 3647篇 |
轻工业 | 9334篇 |
水利工程 | 3144篇 |
石油天然气 | 9536篇 |
武器工业 | 1059篇 |
无线电 | 17523篇 |
一般工业技术 | 26763篇 |
冶金工业 | 11084篇 |
原子能技术 | 4841篇 |
自动化技术 | 19348篇 |
出版年
2024年 | 719篇 |
2023年 | 2333篇 |
2022年 | 4609篇 |
2021年 | 6210篇 |
2020年 | 4682篇 |
2019年 | 4018篇 |
2018年 | 5140篇 |
2017年 | 5585篇 |
2016年 | 5146篇 |
2015年 | 5661篇 |
2014年 | 7318篇 |
2013年 | 8899篇 |
2012年 | 9547篇 |
2011年 | 10236篇 |
2010年 | 8694篇 |
2009年 | 8529篇 |
2008年 | 8406篇 |
2007年 | 7897篇 |
2006年 | 7312篇 |
2005年 | 6245篇 |
2004年 | 4781篇 |
2003年 | 4705篇 |
2002年 | 4743篇 |
2001年 | 4322篇 |
2000年 | 3748篇 |
1999年 | 3318篇 |
1998年 | 2620篇 |
1997年 | 2207篇 |
1996年 | 1976篇 |
1995年 | 1737篇 |
1994年 | 1466篇 |
1993年 | 1242篇 |
1992年 | 1216篇 |
1991年 | 1076篇 |
1990年 | 1089篇 |
1989年 | 1010篇 |
1988年 | 896篇 |
1987年 | 841篇 |
1986年 | 763篇 |
1985年 | 715篇 |
1984年 | 701篇 |
1981年 | 668篇 |
1979年 | 737篇 |
1978年 | 777篇 |
1977年 | 739篇 |
1976年 | 755篇 |
1975年 | 713篇 |
1974年 | 719篇 |
1973年 | 723篇 |
1972年 | 705篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Chuang Yu Yu Yang Ze-xiang Wu Ji-fang Jiang Rao-ping Liao Yong-feng Deng 《Geotextiles and Geomembranes》2021,49(2):413-419
Geosynthetic clay liners (GCLs), which have a very low permeability to water and a considerably high self-healing capacity, are widely used in liner systems of landfills. In this study, a series of experimental tests were carried out under complex conditions on typical commercial GCLs from China. In particular, the effects of pH values and lead ions (Pb2+) were tested in addition to other factors. The swelling properties of natural bentonite encapsulated between geotextile components in the GCLs were tested first. The swelling capacity was reduced rapidly at pH values < 3 and concentrations of Pb2+ >40 mM. Permeability tests on GCLs with different concentrations of lead ions were then performed by using the self-developed multi-link flexible wall permeameter, and data showed that increases in lead ion concentrations greatly improved the permeability. Finally, self-healing capacity tests were conducted on needle-punched GCLs under different levels of damage. Results showed that the GCLs have a good self-healing capacity with small diameter damage holes (2 mm, close to three times the original aperture), but with a damage aperture larger than 15% of the sample area, the self-healing capacity could not prevent leakage; hence, in certain situations it will be necessary to repair the damage to meet the anti-seepage requirement. 相似文献
132.
133.
134.
Verbovitskii Yu. V. Denis R. V. Shtender V. V. Zavalii I. Yu. 《Powder Metallurgy and Metal Ceramics》2015,54(3-4):220-226
Powder Metallurgy and Metal Ceramics - Multiphase La 2 MgNi 9 alloys are synthesized by induction melting. The crystalline structures of all phases in the alloys are determined with X-ray... 相似文献
135.
136.
Elucidation of colour development and microstructural characteristics of Allium sativum fumigated with acetic acid
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Li Li Dan Wang Xihong Li Yu Wang Xiaofeng Ju 《International Journal of Food Science & Technology》2015,50(5):1083-1088
It has been well known that the greening of Allium sativum cloves could be formed after immersed in acetic acid solution. Nonetheless, no investigation was reported on colour development of A. sativum in response to acetic acid vapour until now. In this study, the brief exposure of A. sativum to acetic acid vapour (200–400 ppm) was combined with controlled atmosphere (5%, 20% and 80% CO2) packaging storage to break cell membrane and green garlic. The garlic bulbs were fumigated with acetic acid before controlled CO2 atmosphere packaging for 25 days at 4 °C. Fumigation with 200 ppm acetic acid followed by high CO2 atmosphere packaging (80% CO2) facilitated the garlic greening. It was also verified that γ‐glutamyl transpeptidase was involved in garlic greening in present study, and the compromise of glacial acetic acid vapour fumigation and CO2 gas atmosphere in package stored at low temperature could result in garlic greening as well. 相似文献
137.
138.
139.
Metallurgist - Kinetics of austenite grain growth within a heat-affected zone is studied for low carbon low-alloy steels of different alloying composition. The effect of Ti/N ratio on the metal... 相似文献
140.