全文获取类型
收费全文 | 3008篇 |
免费 | 271篇 |
国内免费 | 153篇 |
专业分类
电工技术 | 112篇 |
综合类 | 190篇 |
化学工业 | 559篇 |
金属工艺 | 186篇 |
机械仪表 | 195篇 |
建筑科学 | 231篇 |
矿业工程 | 85篇 |
能源动力 | 89篇 |
轻工业 | 246篇 |
水利工程 | 53篇 |
石油天然气 | 263篇 |
武器工业 | 31篇 |
无线电 | 246篇 |
一般工业技术 | 367篇 |
冶金工业 | 152篇 |
原子能技术 | 18篇 |
自动化技术 | 409篇 |
出版年
2024年 | 10篇 |
2023年 | 38篇 |
2022年 | 90篇 |
2021年 | 107篇 |
2020年 | 91篇 |
2019年 | 90篇 |
2018年 | 92篇 |
2017年 | 80篇 |
2016年 | 94篇 |
2015年 | 110篇 |
2014年 | 131篇 |
2013年 | 165篇 |
2012年 | 194篇 |
2011年 | 188篇 |
2010年 | 181篇 |
2009年 | 176篇 |
2008年 | 176篇 |
2007年 | 162篇 |
2006年 | 174篇 |
2005年 | 155篇 |
2004年 | 110篇 |
2003年 | 108篇 |
2002年 | 99篇 |
2001年 | 98篇 |
2000年 | 94篇 |
1999年 | 74篇 |
1998年 | 62篇 |
1997年 | 62篇 |
1996年 | 42篇 |
1995年 | 45篇 |
1994年 | 33篇 |
1993年 | 23篇 |
1992年 | 28篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有3432条查询结果,搜索用时 15 毫秒
101.
102.
Haifeng Zhang Peng Zhang Qi Sui Kai Zhao Hong Zhou Luquan Ren 《Journal of Materials Engineering and Performance》2017,26(4):1614-1625
In this study, in effort to improve the sliding wear resistance of gray cast iron under wet lubrication conditions, specimens with different bionic units were manufactured and modified according to bionic theory. Inspired by the structure and appearance of biological wear-resistant skin, two kinds of bionic units were processed by laser on the specimen surfaces. We investigated the wear resistance properties of the samples via indentation method and then observed the wear surface morphology of specimens and the stress distributions. The results indicated that coupling the bionic units enhanced the wear resistance of the cast iron considerably compared to the other samples. We also determined the mechanism of wear resistance improvement according to the results. 相似文献
103.
本文从建立复合养老模式的必要性入手,分析养老职能社会化和养老模式多元化的趋势以及目前社区养老存在的不足,提出适应未来常态化养老需求的复合型养老模式的概念,并在此基础上论述其特征、构建原则和三种不同角度的基本构建模式。 相似文献
104.
论述了润滑油系统中清除异物所需的冲洗设备和冲洗材料,并讨论了冲洗方法和冲洗验收标准,以便为确保压缩机安全开车做好供油准备。 相似文献
105.
Crack-free Sm-doped Bi2Ti2O7 (Sm:BTO) thin films with strong (111) orientation have been prepared on Pt (111) substrates using a chemical solution deposition (CSD) method. The structural properties and crystallizations were studied by X-ray diffraction. The surface morphology and quality were examined using atomic force microscopy (AFM). The insulating and dielectric properties were also evaluated at room temperature. The results demonstrate that the Sm:BTO films exhibit improved electrical performances as compared to the pure Bi2Ti2O7 thin films and suggest a strong potential for utilization in microelectronics devices. 相似文献
106.
Influence of fiber surface treatment on mechanical performance of Xanthoceras sorbifolia bunge husk fibers/PP composites
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The PP Composites containing Xanthoceras sorbifolia Bunge husks fibers with different surface treatments were prepared. The mechanical properties such as tensile properties and impact properties of the composites were investigated. It is revealed that the composites with fibers treated by alkali and the following treatments of silane coupling agents KH570, titanate coupling agent JN‐9A, acetic anhydride, MAPP, or bleach, all performed higher in tensile properties than that with untreated fibers, while lower in impact properties. Meanwhile, all treated fibers performed better thermal stability than untreated fibers. The fibers treated by alkali followed by KH570 treatment were added into PP with different contents. It is found that as the fiber content increases, the elastic modulus and impact strength of the composites increase sharply at first followed by a decrease, while the tensile strength decrease initially and increase with a peak at 10%, then decrease continuously. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41217. 相似文献
107.
The flame‐retardant properties and mechanisms of poly(ethylene terephthalate)/hexakis (para‐allyloxyphenoxy) cyclotriphosphazene systems
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jiawei Li Feng Pan Xiandong Zeng Hong Xu Linping Zhang Yi Zhong Xiaofeng Sui Zhiping Mao 《应用聚合物科学杂志》2015,132(44)
Para‐allyl ether phenol derivative of cyclophosphazene (PACP) was prepared and used as a filler to modify the flame‐retardant properties of poly(ethylene terephthalate) (PET) by melting‐blending. The mechanism of flame‐retardant was discussed and the influences of flame‐retardant contents to the mechanical properties were studied. The results revealed that the incorporation of only 5 phpp PACP (0.37 wt % phosphorus containing) into PET matrix can distinctly increase the flame retardancy of PET/PACP composition, and it has a little effect on the mechanical properties of PET. The high flame‐retardant performance of PET/PACP composite was attributed to the combination of condensed‐phase flame retardant and gas‐phase flame retardant. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42711. 相似文献
108.
109.
110.
硅基液晶(LCOS)是最适合用于全息视频显示的空间光调制器之一,但是受限于小衍射角和低分辨率的特性,当前市场上的LCOS并不完全适用。近年来出现的超常表面(例如,间隙表面等离子体激元)具有独特的特性,提供了一种新的对光传播进行控制的方法。文中采用数值方法研究了在LCOS中插入超常表面结构,旨在解决小衍射角和低分辨率的问题。为了实用化,使用铝作为金属层、三氧化二铝层作为电介质层,生成GSP结构。首先,研究了铝在可见光频率的光学特性以及相应的法布里珀罗共振子模型。然后将初始GSP结构插入到LCOS中,得到液晶中的电场分布,进一步观察液晶中指向矢分布的变化。数值模拟的结果表明,所提出的结构对远场衍射光具有一定的影响,并且全息显示的视场角也发生一些改变。因此,这里提出的在LCOS装置中插入GSP的方案在技术上是可行的。 相似文献