全文获取类型
收费全文 | 587篇 |
免费 | 75篇 |
国内免费 | 119篇 |
专业分类
化学 | 673篇 |
晶体学 | 6篇 |
综合类 | 5篇 |
物理学 | 15篇 |
综合类 | 82篇 |
出版年
2023年 | 5篇 |
2022年 | 12篇 |
2021年 | 13篇 |
2020年 | 23篇 |
2019年 | 24篇 |
2018年 | 19篇 |
2017年 | 21篇 |
2016年 | 31篇 |
2015年 | 26篇 |
2014年 | 20篇 |
2013年 | 54篇 |
2012年 | 39篇 |
2011年 | 24篇 |
2010年 | 25篇 |
2009年 | 34篇 |
2008年 | 45篇 |
2007年 | 46篇 |
2006年 | 38篇 |
2005年 | 45篇 |
2004年 | 33篇 |
2003年 | 31篇 |
2002年 | 25篇 |
2001年 | 12篇 |
2000年 | 18篇 |
1999年 | 21篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 17篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 14篇 |
1991年 | 5篇 |
1989年 | 9篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有781条查询结果,搜索用时 31 毫秒
181.
Lemenovskii D. A. Makarov M. V. Dyadchenko V. P. Bruce A. E. Bruce M. R. M. Larkin S. A. Averkiev B. B. Starikova Z. A. Antipin M. Yu. 《Russian Chemical Bulletin》2003,52(3):607-615
Arylation of ferrocene with substituted biphenyldiazonium tetrafluoroborates afforded 4-bromo-, 4-nitro-, and 4-cyano-4"-ferrocenylbiphenyls. 4-Nitro- and 4-cyano-4"-ferrocenylbiphenyls were studied by X-ray diffraction analysis. In the crystals of 4-nitro-4"-ferrocenylbiphenyl, the molecules are linked via stacking - interactions. 相似文献
182.
183.
Shannon Haymond Jerzy K. Zak Yoshiyuki Show James E. Butler Gerald T. Babcock Greg M. Swain 《Analytica chimica acta》2003,500(1-2):137-144
The spectroelectrochemical responsiveness of an optically transparent diamond electrode (OTE) toward ferrocene was investigated. A freestanding, mechanically polished, boron-doped diamond disk (0.38 mm thick and 8 mm in diameter) served as the OTE for UV-Vis transmission spectroelectrochemical measurements. A specially designed, thin-layer spectroelectrochemical cell was constructed for the measurements in which ferrocene was electrooxidized to ferricinium ion via a one-electron redox reaction. The oxidation reaction product was spectroscopically monitored in the ultraviolet (λ=252, 285 nm) region of the electromagnetic spectrum. Well-defined and highly stable spectroelectrochemical responses were observed for this type of diamond OTE. The results indicate that diamond is a useful OTE material for spectroelectrochemically studying nonaqueous redox reactions. 相似文献
184.
Jaisheila Rajput Alan T Hutton Catherine E Arendse 《Journal of organometallic chemistry》2004,689(9):1553-1568
The preparation of a series of ferrocenyl nitrogen donor ligands including ferrocenylpyridines, ferrocenylphenylpyridines and 1,1′-di(2-pyridyl)ferrocene is described. Coordination studies of the substituted pyridines (L) were carried out with platinum, palladium, rhodium and iridium. This resulted in the preparation of the following types of complexes: [MCl(CO)2(L)] and [M(cod)(L)2]ClO4 where M=Rh or Ir, cod=1,5-cyclooctadiene; [M′Cl2(L)2] where M′=Pt or Pd. The X-ray crystal structure of trans-dichlorobis(3-ferrocenylpyridine)palladium was obtained. The complexes were screened for activity against two human cancer cell lines. At least two of the complexes displayed growth inhibition similar to that of the widely used chemotherapeutic agent, cisplatin. 相似文献
185.
Charles Pedersen's career is reviewed from the time of his early life in Korea and Japan and scientific training in the United States to the present. His 42-year research career was practically and scientifically productive, leading finally to a share of the Nobel prize in chemistry for 1987. Commercially significant accomplishments included a large improvement in the yield of tetraethylead antiknock and discovery of the first oil soluble agents for inhibiting catalytic effects of copper in degradation of petroleum products and rubber. This led to a study of the interactions of metals with chelating agents and the resultant effects on oxidation reactions, thence to the behavior of peroxides and their reactions with substrates. He also discovered the antiknock activity of ferrocene. While studying the effects of ligands on the catalytic behavior of vanadium he discovered the crown compounds and their ability to include alkali metal ions. He devoted the last years of his career to elaborating their chemistry.Taken in part with permission fromCurrent Topics in Macrocyclic Chemistry in Japan, E. Kimura (ed.), Hiroshima University School of Medicine, Hiroshima, 1987. 相似文献
186.
A novel ferroenyl pyrrolizidine derivative containing cyano groups, 2-(4-methylphenyl)-3-ferrocenyl-4,4-dicyanpyrrolizidine (C26H25FeN3 , Mr=435.34), was synthesized in moderate yields via a facile 1.3-dipolar cycloaddition in refluxing toluene and its crystal structure was determined by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a=10.3792(10), b=11.4485(11), c=19.1243(15), β=109.496(4)°, V=2142.2(3)3, Dc=1.350 g/cm3, μ(MoKα)=0.721 mm-1 , Z=4, T=113(2)K, F(000)=912, the final R=0.0586 and wR=0.1664. 相似文献
187.
188.
合成了一种新型的具有光活性和氧化还原活性的两亲性分子——4-(11-二茂铁基正十一烷氧基)偶氮苯甲酸(FcAzCOOH),采用元素分析、核磁共振氢谱和傅里叶变换红外光谱对产物进行了确认与表征.紫外-可见吸收光谱研究表明,FcAzCOOH在四氢呋喃溶液中具有很好的光致异构行为.循环伏安行为研究表明,FcAzCOOH在N,N-二甲基甲酰胺溶液中的电极过程为受扩散控制的可逆过程,紫外光照对FcAzCOOH的电化学行为几乎没有影响. 相似文献
189.
190.
Ferrocene‐based polymers are characterized by their electrochemical activity, good redox properties, thermal, photochemical stability, and liquid crystallinity, and thus they have various applications in different fields. A comprehensive investigation on the synthesis and properties of three novel main‐chain ferrocene‐based polyesters with azobenzene in the side chain (MFPAS) was carried out. The main‐chain ferrocene‐based polyester, poly(N‐phenyldiethanolamine 1,1′‐ferrocene dicarboxylate (PPFD), was synthesized via the solution polycondensation reaction of 1,1′‐ferrocenedicarbonyl chloride with phenyldiethanolamine (PDE). The novel MFPAS were synthesized via the post‐polymerization azo‐coupling reaction of PPFD with three different 4‐substituted anilines including 4‐nitroaniline, 4‐aminobenzoic acid, and 4‐aminobenzonitrile to produce 4‐nitrophenylazo‐functionalized‐PPFD (PPFD‐NT), 4‐carboxyphenylazo‐functionalized‐PPFD (PPFD‐CA), and 4‐cyanophenylazo‐functionalized‐PPFD (PPFD‐CN), respectively. All the synthesized polymers were characterized by 1H NMR spectroscopy, Fourier transform infrared spectroscopy, and UV–visible spectroscopy. In addition, powder X‐ray diffraction patterns were measured for the synthesized polymers. The photoisomerization of the MFPAS was studied. The thermal properties of the MFPAS were studied using thermogravimetric analysis and differential scanning calorimetry. PPFD‐CA and PPFD‐CN were found to be more thermally stable than PPFD‐NT. Finally, the liquid‐crystalline properties of PPFD and the MFPAS were examined using polarized optical microscope. It was found that all the polymers possessed nematic phases and exhibited textures with schlieren disclinations. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献