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   369篇
  免费   0篇
  国内免费   224篇
化学   570篇
力学   5篇
数学   3篇
物理学   15篇
  2019年   2篇
  2018年   2篇
  2015年   1篇
  2014年   2篇
  2012年   8篇
  2011年   7篇
  2010年   4篇
  2009年   112篇
  2008年   149篇
  2007年   37篇
  2006年   87篇
  2005年   86篇
  2004年   28篇
  2003年   15篇
  2002年   9篇
  2001年   5篇
  2000年   11篇
  1999年   16篇
  1998年   1篇
  1997年   5篇
  1996年   1篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1979年   1篇
排序方式: 共有593条查询结果,搜索用时 15 毫秒
491.
1 INTRODUCTION Many efforts have been devoted to the synthesis of metal organophosphonates during the past three decades because of their rich variety of structural chemistry as well as their practical or potential applications in the areas of adsorption/desorption[1, 2], catalysts[3, 4], meso-/microporous materials[5~7] and intercalation chemistry[8~16]. One encouraging deve- lopment direction is the use of phosphonic acids with bi- and trifunctional groups, such as amino, hydroxyl and…  相似文献   
492.
1 INTRODUCTION With the increasing interest in diode-pumped solid state lasers, researches on more efficient new materials for diode pumping become more important. The double borates are a type of excellent laser gain media, for example, Nd3 -doped RAl…  相似文献   
493.
1 INTRODUCTION It has been known that the electron correlation energy of molecular systems was, and still is, one of the most serious bottleneck problems to the chemis- try accuracy of computational quantum chemistry. Since L鰓din[1] gave the definition …  相似文献   
494.
1 INTRODUCTION The quinone structure is common in numerous natural products that are associated with antitumor, antibacterial, antimalarial, and antifungal activities[1]. A variety of heterocyclic quinones containing dif- ferent heteroatom substituents could exhibit such activities through different actions and sometimes even improve the activities[2~5]. On the other hand, organophosphorus compounds continue to receive widespread attention due to their ubiquity in biological systems[6, 7]…  相似文献   
495.
1 INTRUDUCTION The rational design and synthesis of metal-direc- ted supramolecular framework have received much attention in coordination chemistry because of their potential applications in catalysis, molecular selec- tion, non-linear optics, ion exchange and microelec- tronics[1~4]. During the lastdecade, many high-di- mensional coordination complexes have been de- signed and prepared through molecular self-as- sembly process[5~10]. The construction of open metal organic framework, s…  相似文献   
496.
1 INTRODUCTION In recent years, much attention has been focused on the NaxCoO2 system due to its notable properties and potential technologic applications as a cathode material in high-energy density, reversible solid state battery systems[1, 2]. Recently, large thermoelectric power[3~6] in NaxCoO2 and superconductivity (~4 K) in hydrated NaxCoO2yH2O (x = 0.35, y = 1.33) ma- terial have been observed[7]. This hydrated layered phase is the first 3d-transition metal oxide with superco…  相似文献   
497.
Synthesis and Crystal Structure of (C_6N_3H_(18))_2Ti_4O_4(C_2O_4)_7·4H_2O   总被引:1,自引:1,他引:0  
1 INTRODUCTION The open-framework inorganic materials have been synthesized before the early 1980s[1]. Parti- cularly, metal phosphates have been investigated widely during the past few years[2, 3]. In recent years, considerable efforts have been devote…  相似文献   
498.
1 INTRODUCTION The synthesis and study of transition metal com-plexes incorporating organic free radicals have arou-sed great interest in the field of molecular magne-tism[1]. Nitronyl nitroxide radicals (NITR), stable or-ganic radicals, have been widely used as molecularunits in the design and construction of magnetic ma-terials[2~5]. These radicals are especially attractivedue to that their donor atoms can assemble an exten-ded coordination geometry with changing magneticcoupling. A…  相似文献   
499.
朱莉  a  b 彭斌b 凌友b 林原斌  a 《化学学报》2008,66(24):2705-2711
用紫外光谱法、荧光光谱法、黏度法、凝胶电泳法研究了双核钴(II)配合物[Co2(EGTB)Cl2]•(BF4)2•5H2O和DNA的相互作用, 在pH=7.2的缓冲体系中, 求得配合物与DNA的结合常数. 结果表明, 配合物在接近生理条件下能有效地断裂pBR322DNA, 同时可使DNA的粘度增加, 使EB-DNA体系的荧光强度降低. 配合物与DNA的荧光光谱和紫外光谱表明, 配合物与DNA的作用既存在部分插入结合又存在静电结合模式.  相似文献   
500.
李巧霞a  王金意a  徐群杰b  蔡文斌  a 《化学学报》2008,66(20):2302-2304
采用自发沉积法在Ru膜上生成超薄Pt层(简称Ru/Pt膜), 即在开路状态下将电化学还原后的Ru膜浸于除去氧的H2PtCl6溶液中进行自发沉积. 电化学伏安法测量表明, 随着电还原-自发沉积循环次数的增加, 该Ru/Pt膜电极所含Pt组分增加, 且CO吸附层的电氧化峰电位较Pt膜电极上的明显负移. 应用现场衰减全反射表面增强红外光谱法(ATR-SEIRAS)可轻易检测到在该膜电极Pt和Ru位上吸附CO的振动谱峰. 所制Ru/Pt膜电极不仅对CO的电催化氧化具有协同效应, 还可应用于现场ATR-SEIRAS的研究中.  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