全文获取类型
收费全文 | 144篇 |
免费 | 0篇 |
国内免费 | 13篇 |
专业分类
化学 | 135篇 |
力学 | 1篇 |
数学 | 9篇 |
物理学 | 12篇 |
出版年
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 8篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 13篇 |
2007年 | 14篇 |
2006年 | 21篇 |
2005年 | 24篇 |
2004年 | 15篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 171 毫秒
101.
Zhu HF Fan J Okamura TA Zhang ZH Liu GX Yu KB Sun WY Ueyama N 《Inorganic chemistry》2006,45(10):3941-3948
Three novel metal-organic architectures, [Ag3(bta)].1.5H2O (1), [Cd3(bta)2(H2O)7].5H2O (2), and [Cu11(bta)6(Hbta)2(H2O)10].29H2O (3), were obtained by reactions of the corresponding metal salts with a flexible tripodal ligand, benzene-1,3,5-triacetic acid (H3bta), and their structures were determined by single-crystal X-ray diffraction studies. The results revealed that, in complexes 1 and 2, the carboxylate groups of the bta3- ligand adopted varied coordination modes to link metal atoms and further to form three-dimensional structures with open channels occupied by water molecules, while in complex 3, for the first time, the flexible H3bta acted as a secondary building unit to generate a novel nanometer-sized metallocage, which is composed of a Cu(II) paddle wheel (square secondary building units) and bta3-/Hbta2- organic links (triangular secondary building units). The photoluminescence properties of complexes 1 and 2 were investigated, and the results showed that 2 exhibited photoluminescence in the solid state at room temperature. 相似文献
102.
[reaction: see text] A novel and efficient procedure for the generation of the reactive indole-2,3-quinodimethane intermediates from the allenylanilines is described. The indole-2,3-quinodimethane intermediates were captured by several dienophiles to afford the corresponding tetrahydro- and dihydrocarbazole derivatives. This method is significantly different from the previously reported ones, which involve the 1,4-elimination or its related reactions of the indole derivatives that possess suitable substituents at both the C-2 and C-3 positions. 相似文献
103.
104.
Jing Xu Zheng-Shuai Bai Taka-aki Okamura Man-Sheng Chen Wei-Yin Sun Norikazu Ueyama 《Polyhedron》2009
Four new coordination polymers {[Ni(HL)(H2O)]·H2O}n (1), {[Co(HL)(H2O)]·H2O}n (2), {[Co(HL)]·4H2O}n (3) and {[Zn(HL)]·2H2O·0.5C2H5OH}n (4) [H3L = 5-(1H-imidazol-4-ylmethyl)aminoisophthalic acid] have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction analyses. Complexes 1 and 2 display (3, 3)-connected 2D network with (4, 82) topology. While 3 and 4 exhibit a binodal (3, 6)-connected 2D network with a Schläfli symbol (43)2(46, 66, 83). The complexes 1–4 show remarkable thermal stability and 4 exhibits blue fluorescence with maximum emission at 413 nm upon excitation at 362 nm in the solid state at room temperature. In addition, the magnetic measurements of 3 indicate that there are antiferromagnetic interactions between the neighboring Co(II) centers. 相似文献
105.
Fluoride complexation of element 104, rutherfordium 总被引:1,自引:0,他引:1
Haba H Tsukada K Asai M Toyoshima A Akiyama K Nishinaka I Hirata M Yaita T Ichikawa S Nagame Y Yasuda K Miyamoto Y Kaneko T Goto S Ono S Hirai T Kudo H Shigekawa M Shinohara A Oura Y Nakahara H Sueki K Kikunaga H Kinoshita N Tsuruga N Yokoyama A Sakama M Enomoto S Schädel M Brüchle W Kratz JV 《Journal of the American Chemical Society》2004,126(16):5219-5224
Fluoride complexation of element 104, rutherfordium (Rf), produced in the 248Cm(18O,5n)261Rf reaction has been studied by anion-exchange chromatography on an atom-at-a-time scale. The anion-exchange chromatographic behavior of Rf was investigated in 1.9-13.9 M hydrofluoric acid together with those of the group-4 elements Zr and Hf produced in the 18O-induced reactions on Ge and Gd targets, respectively. It was found that the adsorption behavior of Rf on anion-exchange resin is quite different from those of Zr and Hf, suggesting the influence of relativistic effects on the fluoride complexation of Rf. 相似文献
106.
Sagara Y Mitsuya M Uchiyama M Ogino Y Kimura T Ohtake N Mase T 《Chemical & pharmaceutical bulletin》2005,53(4):437-440
Synthesis and structure-activity relationship of a new class of muscarinic M(3) selective antagonists were described. In the course of searching for a muscarinic M(3) antagonist with a structure distinct from those of the 2-(4,4-difluorocyclopentyl)-2-phenylacetamide derivatives, we identified a thiazole-4-carboxamide derivative (1) as a lead compound in our in-house chemical collection. Since this compound (1) showed relatively low binding affinity (K(i)=140 nM) for M(3) receptors in the human binding assays, we tried to improve its potency and selectivity for M(3) over M(1) and M(2) receptors by derivatization of 1 through a combinatorial approach. A solution-phase parallel synthesis effectively contributed to the optimization of each segment of 1. Thus, we have identified a cyclooctenylmethyl derivative (3e) and a cyclononenylmethyl derivative (3f) as representative M(3) selective antagonists in this class. 相似文献
107.
Synthesis of ordered mesoporous carbons with channel structure from an organic-organic nanocomposite 总被引:3,自引:0,他引:3
Tanaka S Nishiyama N Egashira Y Ueyama K 《Chemical communications (Cambridge, England)》2005,(16):2125-2127
Mesoporous carbons with ordered channel structure (COU-1) have been successfully fabricated via a direct carbonization of an organic-organic nanocomposite. 相似文献
108.
Transparent photochromic inorganic/organic hybrid gels involving the Chemically bonded spirobenzopyran moiety have been prepared by the sol–gel reactions using tetraethoxysilane, the silanol-terminated oligomeric poly(dimethylsiloxane), and spirobenzopyrans with the alcoxysilyl groups. 相似文献
109.
Incorporation of organic groups within the channel wall of spin-on mesostructured silica films by a vapor infiltration technique 总被引:1,自引:0,他引:1
Tanaka S Kaihara J Nishiyama N Oku Y Egashira Y Ueyamat K 《Langmuir : the ACS journal of surfaces and colloids》2004,20(9):3780-3784
Organically functionalized mesoporous silica films have been prepared by a novel synthetic procedure that involves spin-coating of mesostructured silica films and a vapor infiltration (VI) technique, using organosiloxanes, before the removal of surfactant. The VI-treated mesostructured films were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and a field emission scanning electron microscope (FE-SEM). Nitrogen adsorption/desorption measurements were performed using films attached with a silicon substrate. The XRD and FE-SEM measurements show that the mesochannel wall, densified and modified with organosilyl groups by the VI treatment, hardly contracts under calcination. FE-SEM observations for the films' cross section support the view that organosiloxane vapor is not deposited on the surface of the film. These results show that organosiloxane molecules penetrate the film and are selectively incorporated into the silica wall. Thus, hydrophobic mesoporous silica films can be synthesized without a reduction in pore size, a result that cannot be attained by conventional grafting and co-condensation methods. The excellent high porosity and hydrophobicity of the mesostructured composite films may be of advantage for next-generation low-k dielectric films. 相似文献
110.
Designing a capsule catalyst and its application for direct synthesis of middle isoparaffins 总被引:1,自引:0,他引:1
He J Yoneyama Y Xu B Nishiyama N Tsubaki N 《Langmuir : the ACS journal of surfaces and colloids》2005,21(5):1699-1702
A catalyst in the form of a capsule catalyst was prepared by coating HZSM5 membrane on a preshaped Co/SiO2 catalyst pellet. The capsule catalyst with HZSM5 membrane exhibited excellent selectivity for light hydrocarbon synthesis, especially for isoparaffin synthesis from syngas (CO + H2). Long-chain hydrocarbon formation was totally suppressed by the zeolite membrane. The modification of membrane and core catalyst significantly improved the catalytic properties of these new kinds of capsule catalysts. 相似文献