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121.
采用紫外 可见光谱法研究了在pH 6 5的缓冲溶液中Cu(Ⅱ )离子对多巴色素的催化作用。在通氮除氧的体系中 ,Cu(Ⅱ )离子显著加快多巴色素 (DC)于 4 75nm波长的褪色速度 ,并同时出现在 30 0~ 80 0nm波长范围内的全程吸收。实验结果表明 :Cu(Ⅱ )离子催化重排多巴色素生成的主要产物为 5 ,6 二羟基吲哚 2 羧酸 (DHICA) ,其反应前期对于DC为动力学一级反应 ;而且Cu(Ⅱ )离子可进一步催化 5 ,6 二羟基吲哚(DHI)和DHICA形成吲哚醌 (即吲哚 5 ,6 醌和吲哚 5 ,6 醌 2 羧酸 )的反应 ,吲哚醌一经生成 ,立即聚合形成黑色素。 相似文献
122.
1,5-萘二胺衍生物的光谱分析及发光性能研究 总被引:5,自引:2,他引:3
合成了一种纯度较高的1,5-萘二胺衍生物(NPN),制备了NPN薄膜.利用紫外-可见吸收光谱和荧光发射光谱研究了NPN的发光行为,并结合电化学循环伏安法研究了其电子能级结构.结果表明,NPN的荧光光谱表现出明显的溶剂效应,认为其发生了从电子给体N原子到电子受体芳环之间的分子内电子转移,形成分子内电子转移络合物;从NPN薄膜与其溶液的吸收光谱峰值比较中看出吸收峰红移,认为薄膜中分子形成"J-聚集体";NPN的HOMO能级为-5.74 eV,光学禁带为2.79 eV;在365 nm紫外光的激发下,产生发光峰在448.6 nm附近、谱线带宽为72.6 nm的蓝光发射,发光亮度高,色纯度高. 相似文献
123.
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125.
M. P. Pasechnik D. V. Tolkachev S. V. Matveev N. N. Bubnov E. I. Matrosov M. I. Kabachnik 《Russian Chemical Bulletin》1993,42(7):1140-1144
The complexation ofcis,cis-1,3,5-tri[2-(diphenylphosphinyl)ethylamino]cyclohexane (L1) with Cu2+ and Co2+ cations has been studied in different solvents by means of UV-Vis, ESR, and IR spectroscopy. It has been shown that in the CuL1 complex the metal ion is pentacoordinated by three nitrogen atoms and two phosphinyl groups of the ligand and has a tetragonal-pyramidal environment. The conformation of the coordination polyhedron for the CuL1 complex depends on the solvent. In the CoL1 complex, as well as in the CoL2 complex, where L2 is 1,4,7-tris(2-diphenylphosphinylethyl)-1,4,7-triazacyclononane, the Co2+ ion has an octahedral environment and is bound to all donor atoms of the ligands.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1199–1202, July, 1993.The authors are grateful to A. G. Matveeva and Yu. M. Polikarpov for the fruitful discussions. 相似文献
126.
Tadeusz Ossowski Hanna Sulowska Tomasz Karbowiak Dorota Zarzeczanska B?a?ej Gierczyk Grzegorz Schroeder 《Central European Journal of Chemistry》2006,4(1):13-28
Formation of complexes of A18C6-Dns and metal cations (Ca2+, Sr2+, Ba2+ and Mg2+) in acetonitrile has been studied by NMR, absorption and fluorescence spectroscopy and PM5 semi-empirical methods. A18C6-Dns
forms stable complexes with Ca2+, Sr2+ and Ba2+ cations. The stability constants of various complexes are determined by different methods and their structures are visualised
by the PM5 semi-empirical calculations. 相似文献
127.
Novel π-conjugated donor compounds based on the strong electron-donating ferrocene moiety and dithiafulvalene donors exhibited increased electron donor ability. The ferrocenylketones 4a,b, 5, 8 and 9 were synthesized via described methods, and allowed to react with 2-dimethoxyphosphinyl-1,3-benzodithiole (13) in the presence of n-BuLi at −78°C in dry THF to afford the corresponding ferrocene-dithiafulvalenes 14a,b, 18, 19 and 1,1′-bis(benzo-1,3-dithiol-2-ylidene)ethyl]ferrocene (15). Electrochemical properties of these new donor compounds were studied using cyclic voltammetry (CV) and UV-Vis spectra. CV and absorption spectra of the new compounds were studied in comparison with ferrocene (6) and dibenzo-tetrathiafulvalene DB-TTF 3. Two-electron and three-electron redox behaviors were observed as two waves. The absorption spectra showed a red-shift with a slight increase in the absorption intensities. 相似文献
128.
以干燥的正己烷为溶剂, 在N2气保护下, 研究了金属有机化合物双(1,2-二苯基环戊二烯基)二氯化锆(2)、 双(4-甲基-1,2-二苯基环戊二烯基)二氯化锆(3)和双(1,2,4\|三苯基环戊二烯基)二氯化锆(4)的发光光谱行为. 研究结果表明, 该系列化合物具有良好的发光性能, 且荧光光谱的发射波长可通过改变环戊二烯基4位上的取代基R进行调节. 发射光波长大小顺序为Ph>CH3>H. 相似文献
129.
氨基甲酸酯型脱氧胆酸分子钳对中性分子的识别性能研究 总被引:3,自引:0,他引:3
利用差紫外光谱法考察了新型分子钳1~6对苯胺、对硝基苯胺、对甲氧基苯胺等中性分子的识别性能, 测定了25 ℃下, 在CHCl3中主客体间的结合常数(Ka)和自由能变化(ΔG0). 结果表明, 所有分子钳主体对所考察的客体分子显示良好的识别作用, 主客体间形成1∶1型主客体络合物. 识别作用的主要推动力为多重氢键和π-π重叠等的作用. 讨论了主客体间形状、大小匹配和几何互补及识别模式等因素对识别能力的影响, 并利用核磁共振氢谱与计算机模拟作为辅助手段对实验结果进行了解释. 相似文献
130.
A. I. Kokorin N. N. Vlasova A. A. Pridantsev N. K. Dividenko 《Russian Chemical Bulletin》1997,46(10):1670-1676
The formation of ternary surface complexes of copper(II) with one or two molecules of 2,2′-bipyridine (bpy) or α-picolinic
acid (Hpic), which were obtained after adsorption on the silica surface in different ways, was studied by electronic and ESR
spectroscopy. Coordination of the ligands, which were preliminarily adsorbed by copper ions, afforded only 1∶1 ternary surface
complexes. In both cases, coordinatively more saturated ternary surface complexes were formed only when Cu(bpy)2
2+ and Cu(pic)2 were adsorbed on the SiO2 surface from solutions. The compositions and structures of the ternary surface complexes containing bipyridine ligands are
temperature independent, whereas in the picolinate-containing ternary surface complexes, the coordination spheres of the adsorbed
complexes are rearranged as the temperature changes.
Presented at the First Moscow Workshop on Highly Organized Catalytic Systems (June 19, 1997).
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1765–1771, October, 1997. 相似文献