全文获取类型
收费全文 | 4648篇 |
免费 | 207篇 |
国内免费 | 239篇 |
专业分类
电工技术 | 18篇 |
综合类 | 270篇 |
化学工业 | 525篇 |
金属工艺 | 1228篇 |
机械仪表 | 692篇 |
建筑科学 | 72篇 |
矿业工程 | 310篇 |
能源动力 | 14篇 |
轻工业 | 496篇 |
水利工程 | 4篇 |
石油天然气 | 67篇 |
武器工业 | 34篇 |
无线电 | 309篇 |
一般工业技术 | 729篇 |
冶金工业 | 176篇 |
原子能技术 | 60篇 |
自动化技术 | 90篇 |
出版年
2024年 | 16篇 |
2023年 | 47篇 |
2022年 | 55篇 |
2021年 | 52篇 |
2020年 | 76篇 |
2019年 | 62篇 |
2018年 | 71篇 |
2017年 | 120篇 |
2016年 | 94篇 |
2015年 | 116篇 |
2014年 | 217篇 |
2013年 | 178篇 |
2012年 | 218篇 |
2011年 | 338篇 |
2010年 | 239篇 |
2009年 | 283篇 |
2008年 | 230篇 |
2007年 | 325篇 |
2006年 | 326篇 |
2005年 | 297篇 |
2004年 | 261篇 |
2003年 | 235篇 |
2002年 | 203篇 |
2001年 | 189篇 |
2000年 | 165篇 |
1999年 | 140篇 |
1998年 | 104篇 |
1997年 | 106篇 |
1996年 | 91篇 |
1995年 | 82篇 |
1994年 | 42篇 |
1993年 | 48篇 |
1992年 | 29篇 |
1991年 | 14篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
排序方式: 共有5094条查询结果,搜索用时 15 毫秒
1.
Chengkai Li Zheyi Zhang Haifei Zhan Zhuoqun Zheng Jingshuai Bai Yuantong Gu 《大分子材料与工程》2021,306(10):2100292
Low-dimensional carbon nanostructures are ideal nanofillers to reinforce the mechanical performance of polymer nanocomposites due to their excellent mechanical properties. Through molecular dynamics simulations, the mechanical performance of poly(vinyl alchohol) (PVA) nanocomposites reinforced with a single-layer diamond – diamane is investigated. It is found the PVA/diamane exhibits similar interfacial strengths and pull-out characteristics with the PVA/bilayer-graphene counterpart. Specifically, when the nanofiller is fully embedded in the nanocomposite, it is unable to deform simultaneously with the PVA matrix due to the weak interfacial load transfer efficiency, thus the enhancement effect is not significant. In comparison, diamane can effectively promote the tensile properties of the nanocomposite when it has a laminated structure as it deforms simultaneously with the matrix. With this configuration, the interlayer sp3 bonds endows diamane with a much higher resistance under compression and shear tests, thus the nanocomposite can reach very high compressive and shear stress. Overall, enhancement on the mechanical interlocking at the interface as triggered by surface functionalization is only effective for the fully embedded nanofiller. This work provides a fundamental understanding of the mechanical properties of PVA nanocomposites reinforced by diamane, which can shed lights on the design and preparation of next generation high-performance nanocomposites. 相似文献
2.
预处理工艺对硬质合金与金刚石膜间粘结力的影响 总被引:1,自引:0,他引:1
在两种经不同预处理的硬质合金YG8基底上,采用微波等离子体化学气相沉积法,在微波功率2kW,压强4.0kPa和6.5kPa,CH4和H2流量分别为1.6cm/s和100.0cm/s的条件下生长金刚石薄膜。利用X射线衍射检测了金刚石薄膜是否存在,用拉曼光谱分析了薄膜的质量,用金相显微镜观察了薄膜的洛氏硬度压痕,标定并比较了不同预处理工艺膜与基底的结合力。实验结果表明,不同的预处理方法对于粘结力的影响不大,最主要的因素是钴含量的多少。 相似文献
3.
4.
扫描电子显微研究表明,化学汽相沉积的金刚石薄膜中晶粒大小比较均匀。但随着沉积时间和薄膜厚度的增加,晶粒逐渐变大,且每一层内,存在少量的大金刚石颗粒,讨论了晶粒尺寸变化和大晶粒形成的原因和机制。 相似文献
5.
6.
7.
Abstract— We have developed a process to fabricate optical components, such as a lens, prism, or diffuser, directly on to a glass substrate. Processes include precision mastering by diamond cutting and multi‐layer photopolymer (2P) molding to realize flat surfaces and the integration of multiple components with an alignment within a few micrometers. 相似文献
8.
在对81/2B125金刚石钻头进行有限元计算分析后,找出最大应力点在金刚石钻头冠部切削告处。通过改变各相关尺寸和结构型式,用有限元法模拟试验过程,在给定结构参数和工艺参数情况下获得多组数据。根据专业知识,参考有限元计算获取的各组数据变化特征,选出拟合较好的公式类型,再采用回归分析方法确定待定系数,最后得出工程上实用的金刚石钻头强度验算公式。用这个公式对81/2B461W和121/4B331金刚石钻头进行了强度验算,经改进设计后钻头在现场使用取得了良好的效果。 相似文献
9.
H. -C. Chiao H. -L. Lin X. -T. Li C. -X. Ding 《Journal of Thermal Spray Technology》1992,1(2):111-115
Diamond growth with rates up to 100 to 140 μm/hr was achieved using an oxygen-acetylene combustion spraying technique in an
atmospheric environment. Investigations on the processing indicated that the gas flow ratio, substrate position, substrate
temperature, temperature distribution, and substrate pretreatment were the most important factors affecting the growth of
diamond crystals. Evaluation by means of X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and electron
probe microanalysis showed that the synthesized diamond was nearly perfect in morphology, structure, and purity. 相似文献
10.
Yen-Kang Liu Pei-Lum Tso 《The International Journal of Advanced Manufacturing Technology》2003,22(5-6):396-400
Grinding is the most suitable process for manufacturing good quality diamond tools. In this paper, diamond wheels have been studied. From the grinding of polycrystalline diamond (PCD) insets, the effects of certain factors such as the bonding material, the grit size and structure of a diamond wheel have been investigated. It is concluded that vitrified bond diamond wheels are the most suitable for grinding PCDs and the recommended grit size is mesh number 1000, which can get a good surface quality within an appropriate time. The wheel structure is another important factor. Rougher wheels (mesh #800, #1000) with the softer grade scale P yield a higher material removal rate (MRR) than scale Q. However, a finer wheel (mesh #1200) needs a tougher structure to promote its grinding ability and to have a higher MRR. 相似文献