首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   465篇
  免费   1篇
  国内免费   4篇
综合类   18篇
化学工业   319篇
金属工艺   7篇
机械仪表   2篇
建筑科学   3篇
矿业工程   2篇
能源动力   13篇
轻工业   7篇
石油天然气   61篇
无线电   5篇
一般工业技术   20篇
冶金工业   1篇
原子能技术   9篇
自动化技术   3篇
  2023年   1篇
  2022年   4篇
  2021年   4篇
  2020年   6篇
  2019年   1篇
  2018年   6篇
  2017年   6篇
  2016年   3篇
  2015年   7篇
  2014年   14篇
  2013年   28篇
  2012年   17篇
  2011年   26篇
  2010年   13篇
  2009年   19篇
  2008年   20篇
  2007年   27篇
  2006年   26篇
  2005年   20篇
  2004年   27篇
  2003年   23篇
  2002年   13篇
  2001年   12篇
  2000年   13篇
  1999年   14篇
  1998年   18篇
  1997年   11篇
  1996年   14篇
  1995年   22篇
  1994年   15篇
  1993年   12篇
  1992年   7篇
  1991年   10篇
  1990年   1篇
  1989年   1篇
  1988年   5篇
  1987年   1篇
  1985年   1篇
  1984年   2篇
排序方式: 共有470条查询结果,搜索用时 15 毫秒
71.
尼龙1010/乙丙共聚物共混体系形态与性能研究   总被引:3,自引:0,他引:3  
在过氧化二异丙苯(DCP)的引发下,用反应挤出的方法制备了乙丙共聚物接枝甲基丙烯酸环氧丙酯(EPM-g-GMA)。用Brabender单螺杆挤出机制备了不同组成的EPM/尼龙1010及EPM-g-GMA/尼龙-1010的共混物,用电子显微镜观察了不同共混组成的形态,与EPM/尼龙1010共混体系相比,EPM-g-GMA/尼龙1010体系中EPM在尼龙1010中分散相尺寸明显降低,EPM-g-GMA  相似文献   
72.
张汝义 《粘接》1995,16(3):13-14
介绍了聚乙烯接枝马来酸酐共聚物与金属的粘接强度,并对接枝率与粘接强度的关系进行了研究。结果发现,接枝共聚物的粘接强度明显优于聚乙烯,它与金属的180°剥离强度可达140N/cm,剪切强度可达10MPa,而且,随着接枝共聚物接枝率的增加,其粘接强度缓慢增加,最终达到最大值。  相似文献   
73.
反应型共聚物相容剂在聚合物合金中的应用   总被引:4,自引:0,他引:4  
反应型共聚物相容剂所含的反应官能团与共混物中聚合物的相关的官能团发生化学反应,从而改善不相容聚合物共混物的相容性。本文介绍了反应型共聚物相容剂的分子设计,合成及其应用。  相似文献   
74.
In this study, it was aimed to overcome disadvantages of polypyrrole films like water up taking and resulting low stability, via copolymerization of pyrrole and N-methyl pyrrole and preparing their bilayer films. Poly(N-methyl pyrrole) coating was synthesized electrochemically on mild steel and its corrosion performance has been investigated in 3.5% NaCl aqueous solution, by using electrochemical impedance spectroscopy (EIS), anodic polarization curves and open circuit potential-time relation. This coating was found to have lower protection efficiency than single poly(pyrrole) coating. This case was related to weak adsorption behavior of poly(N-methyl pyrrole) film on mild steel. On the other hand, when this film was applied as a top coat on polypyrrole coated sample; the obtained coating system hindered the attack of corrosive environment and protected mild steel efficiently. The underlying poly(pyrrole) film was strongly adherent and the top poly(N-methyl pyrrole) coat improved barrier property by decreasing permeability and water mobility. Poly(pyrrole-co-N-methyl pyrrole) has also been synthesized from aqueous oxalic acid solutions containing various ratios of these two monomers. The copolymerization rate and protective behavior of copolymer were strongly affected by the monomer concentration ratio. The ratio of 1:3 (N-methyl pyrrole/pyrrole) gave the most protective copolymer coating and it exhibited better barrier property than single PPy. This was related to introduction of -CH3 group which creates hydrophobic effect, when compared to -NH group of pyrrole unit. However, the solution with the ratio of 1:1 yielded a coating which had lower protection efficiency than single poly(pyrrole) film. This behavior was attributed to significant decrease in adsorption strength as the ratio of n-methyl pyrrole increased.  相似文献   
75.
Aqueous sodium oxalate (NaOX) solutions both without (1) and with (2) p-toluenesulfonic acid (p-TSA) were used to synthesize a poly(aniline-co-o-anisidine) (PANI-co-POA) film on mild steel (MS). Polarization of the substrate in p-TSA containing NaOX solution mixture led to the passivation of the surface mainly via the formation of an iron(II) oxalate layer. Copolymer coatings showed that p-TSA + NaOX solution mixture was a suitable medium for the deposition of a uniform, compact and strongly adherent PANI-co-POA coating on MS electrode. Similar coating was achieved when NaOX solution was used free of p-TSA. It was observed that addition of p-TSA in NaOX solution provided also an increase in electropolymerization rate. Evaluation of the anticorrosion performance of copolymer coatings in 3.5% NaCl solution was investigated by using AC impedance spectroscopy (EIS) technique and anodic polarization curves. Both copolymer coatings exhibited a significant physical barrier property against the attack of corrosive products on mild steel, in longer periods.  相似文献   
76.
采用溶液聚合反应合成了2-丙烯酰胺基-2-甲基丙磺酸(AMPS)与单体I的二元共聚物,用作钻井液降黏剂,通过正交实验,确定了共聚物的合成条件为反应温度55℃,引发剂用量1%,单体配比AMPS:I=1:1(质量比),用红外光谱和差热分析法表征了共聚物的组成特征及其热稳定性。结果表明,共聚物的抗温能力可达到200℃以上。  相似文献   
77.
Jing Quan 《Polymer》2007,48(9):2595-2604
A facile and regioselective enzymatic synthesis approach to prepare polymerizable lipophilic chlorphenesin vinyl esters was developed in this research. The influence of different organic solvents, enzyme sources, reaction time and the acylation reagent on the synthesis of chlorphenesin vinyl esters was investigated. Then the polymerizable monomers 1-O-vinylsuccinyl-chlorphenesin (OVSC) and 1-O-vinyladipoyl-chlorphenesin (OVAC) were homopolymerized using AIBN as the initiator. The obtained polymeric prodrugs were characterized with IR, NMR and GPC analyzes. The poly-OVSC has Mn of 1.35 × 104 and Mw/Mn of 1.95, and the poly-OVAC has Mn of 2.37 × 104 and Mw/Mn of 4.30. Moreover, 6-O-vinyladipoyl-d-glucose (OVAG), a biocompatible monomer, was copolymerized with OVSC and OVAC. Polymeric prodrugs of chlorphenesin with saccharide branches were successfully obtained with high molecular weight.  相似文献   
78.
采用冲击实验、拉伸实验、超景深三维显微镜、扫描电镜和分光光度计等手段,对PVC/SBS/MBS三元共混体系的冲击强度、拉伸强度、形态结构以及光学透明性等进行了研究。实验结果表明,MBS能有效改善PVC/SBS共混体系的界面相容性。当SBS和MBS的总量不变时,随着MBS相对含量的增加,共混体系的缺口冲击强度逐渐增加,透光率在m(MBS)/m(SBS)=28/80时达到最大值,光学透明性能最好。  相似文献   
79.
研究了本体法甲基丙烯酸甲酯-N-环己基马来酰亚胺二元共聚体系的组成对共聚物的光学性能、热性能及力学性能的影响。实验结果表明,当-N-环己基马来酰亚胺用量为甲基丙烯酸甲酯量的2.5%时,共聚物的玻璃化转变温度比纯聚甲基丙烯酸甲酯提高了12.3℃;热分解温度提高了41.1℃;硬度及透明性也均有所提高。  相似文献   
80.
研究了以二甲苯为溶剂,过氧化二异丙苯(DPC)为引发剂,采用高压溶液法制备了丙烯腈-聚丙烯接枝共聚物(APG)。讨论了反应时间、反应温度、引发剂(DCP)浓度、单体(An)浓度等条件对接枝率的影响;并用傅立叶变换红外光谱仪、X-射线衍射对其结构进行表征。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号