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81.
Two two-dimensional coordination polymers,[Cd(μ1,3-SCN-)2(μ1,6-L)]n 1 and [Co(μ1,3-SCN-)2(μ1,6-L)]n 2,have been synthesized with 2,3-dimethylpyrazine-1,4-dioxide (L) and thiocyanate as mixed bridging ligands,and their crystal structures were determined by X-ray crystallography.Both crystals belong to monoclinic system,space group C2/c.The other crystal parameters are as follows:for complex 1:a = 9.732(3),b = 14.658(5),c = 8.811(3) (A),β =102.935(4)°,Z = 4,V = 1225.1(7)(A)3,CsHsCdN4O2S2,Mr = 368.71,Dc.-- 1.999 g/cm3,F(000) =720 andμ = 2.117 mm-1;for complex 2:a = 9.528(7),b = 14.563(11),c = 8.415(6) (A),β =102.195(9)°,V= 1141.3(14) (A)3,Z = 4,C8H8CoN4O2S2,Mr = 315.23,Dc = 1.835 g/cm3,F(000) =636 andμ = 1.863 mm-1.The two complexes show similar two-dimensional sheet structures.Along the c axis one-dimensional chains are constructed by the coordination of Cd(Ⅱ) (or Co(Ⅱ))ions with μ1,6-L bridging ligand,and the μ1,3-SCN- bridging ligands make the chains connect to each other,resulting in the formation of a two-dimensional sheet on the ac plane. 相似文献
82.
A theorem for convolution integrals is proved and then applied to extend the second zero-separation theorem to the bridge functionb(r) and direct-correlation tail functionsd(r). This theorem allows us to exactly relateb(r)/r andd(r)/ratr=0 for the hard-sphere fluid to the contact value of the radial distribution functiong(r) atr=
+. From this we obtain immediately the exact values of b(r)/r and d(r)/r atr=0 through second order in number density . Using our results to compare the exact and Percus-Yevick (PY) bridge function, we find that they differ significantly. After obtaining the bridge function and tail function and their derivatives atr=0 andr= through, we suggest new approximations forb(0) andd(0) as well as an analytical integral-equation theory to improve the PY approximation in the pure hard-sphere fluid. The major deficiency of that approximation has been its poor assessment of the cavity function inside the hard-core region. Our theory remedies this defect in a way that yields ay(r) that is self-consistent with respct to the virial and compressibility relations and also the two zero-separation relations involvingy(r) and its spatial derivative atr=0. 相似文献
83.
《Journal of Coordination Chemistry》2012,65(9):1021-1027
A three-dimensional supramolecular compound [Mn(N3)2(H2O)3(hmt)] 2 , where hmt stands for hexamethylenetetramine, was synthesized and characterized by IR, crystal structure and magnetic susceptibility. The compound [Mn(N3)2(H2O)3(hmt)] n , crystallizes in the orthorhombic system, space group Pn 21 a, with a = 6.5201(9), b = 9.322(2), c = 22.192(3) Å, β = 90° and Z = 2. The Mn atom is coordinated in an octahedral arrangement by three nitrogen atoms from three azido ions, and three oxygen atoms from three water molecules, respectively. The azide ligand bridges Mn atoms in μ-1,3 fashion, forming a zigzag chain. Hmt connected with the zigzag chain by hydrogen bonds, to form a three-dimensional supramolecular structure. The magnetic susceptibility data show that there is an antiferromagnetic exchange interaction in the title compound. The data were modeled using an infinite chain model leading to J = -4.8 cm?1. 相似文献
84.
Accurate modeling of wind-induced loads on bridge decks is critical to ensure the functionality and survivability of long-span bridges. Over the last few decades, several schemes have emerged to model bridge behavior under winds from an aerodynamic/aeroelastic perspective. A majority of these schemes rely on the quasi-steady (QS) theory. This paper systematically compares and assesses the efficacy of five analytical models available in the literature with a new model presented herein. These models include: QS theory-based model, corrected QS theory-based model, linearized QS theory-based model, semi-empirical linear model, hybrid model, and the proposed modified hybrid model. The ability of these models to capture fluid memory and nonlinear effects either individually or collectively is examined. In addition, their ability to include the effects of turbulence in the approach flow on the bridge behavior is assessed. All models are compared in a consistent manner by utilizing the time domain approach. The underlying role of each model in capturing the physics of bridge behavior under winds is highlighted and the influence of incoming turbulence and its interaction with the bridge deck is examined. A discussion is included that focuses on a number of critical parameters pivotal to the effectiveness of corresponding models. 相似文献
85.
The palladacycle [Pd(μ-O2CMe){κ2C,N-4-MeC6H3N(Me)NO}]2 readily undergoes bridge cleavage reactions with a variety of compounds containing donor functionalities including thioamides, 8-hydroxyquinoline, thioureas, selenoureas, acetylacetone derivatives, dithiocarbamates, xanthates, as well as bidentate N-donors to afford either the monomeric, neutral Pd(II) complexes [Pd{κ2C,N-4-MeC6H3N(Me)NO}{L-L}] or the monocationic complexes [Pd{κ2C,N-4-MeC6H3N(Me)NO}(N-N)]PF6 in high yields. A series of 15 different complexes was prepared and fully characterised spectroscopically and, in some cases, by X-ray diffraction. It was also found that the dithiocarbamato complex undergoes a disproportionation reaction in solution to give the bis(cyclometallated) complex [Pd{κ2C,N-4-MeC6H3N(Me)NO}2] as well as the bis(dithiocarbamato) complex [Pd{κ2S-S2CNEt2}2]. 相似文献
86.
87.
Density Function Theory Study on Effects of Different Energetic Substituent Groups and Bridge Groups on Performance of Carbon-Linked Ditetrazole 2N-Oxides 下载免费PDF全文
Based on the parent tetrazole 2N-oxide, six series of novel carbon-linked ditetrazole 2N-oxides with different energetic substituent groups (-NH2, -N3, -NO2, NF2, -NHNO2) and energetic bridge groups (-CH2-, -CH2-CH2-, -NH-, -N=N-, -NH-NH-) were designed. The overall performance and the effects of different energetic substituent groups and energetic bridge groups on the performance were investigated by density functional theory and electrostatic potential methods. The results showed that most of designed compounds have oxygen balance around zero, high heats of formation, high density, high energy, and acceptable sensitivity, indicating that tetrazole N-oxide is a useful parent energetic compound employed for obtaining high energy compounds, even only combined with some very common energetic substituent groups and bridge groups. Comprehensively considering the effects on energy and sensitivity, the -NO2, -NF2, -NH-and -NH-NH-are appropriate substituent groups for combining tetrozale N-oxide to design new energetic compounds, while -NH2, -N3, -CH2-CH2-, and -N=N-are inappropriate. 相似文献
88.
Dr. Gang Wang Yan Wu Dr. Zhujie Li Prof. Zaizhu Lou Qingqing Chen Yifan Li Prof. Dingsheng Wang Prof. Junjie Mao 《Angewandte Chemie (International ed. in English)》2023,62(13):e202218460
Developing highly efficient and stable photocatalysts for the CO2 reduction reaction (CO2RR) remains a great challenge. We designed a Z-Scheme photocatalyst with N−Cu1−S single-atom electron bridge (denoted as Cu-SAEB), which was used to mediate the CO2RR. The production of CO and O2 over Cu-SAEB is as high as 236.0 and 120.1 μmol g−1 h−1 in the absence of sacrificial agents, respectively, outperforming most previously reported photocatalysts. Notably, the as-designed Cu-SAEB is highly stable throughout 30 reaction cycles, totaling 300 h, owing to the strengthened contact interface of Cu-SAEB, and mediated by the N−Cu1−S atomic structure. Experimental and theoretical calculations indicated that the SAEB greatly promoted the Z-scheme interfacial charge-transport process, thus leading to great enhancement of the photocatalytic CO2RR of Cu-SAEB. This work represents a promising platform for the development of highly efficient and stable photocatalysts that have potential in CO2 conversion applications. 相似文献
89.
Johannes Tophøj Rasmussen Georges-Henri Cottet Jens Honoré Walther 《Journal of computational physics》2011,230(17):6742-6755
We present a novel multiresolution Vortex-In-Cell algorithm using patches of varying resolution. The Poisson equation relating the fluid vorticity and velocity is solved using Fast Fourier Transforms subject to free space boundary conditions. Solid boundaries are implemented using the semi-implicit formulation of Brinkman penalization and we show that the penalization can be carried out as a simple interpolation. We validate the implementation against the analytic solution to the Perlman test case and by free-space simulations of the onset flow around fixed and rotating circular cylinders and bluff body flows around bridge sections. 相似文献
90.
本文对非线性光学材料乙酰二茂铁缩肼基硫代甲酸苄酯 (HLSB)的镍 /钴配合物Ni(LSB) 2 /Co(LSB) 2进行了电化学和现场红外光谱电化学的比较研究 ,结果表明 ,平面型镍配合物桥联双二茂铁体系中的电子离域程度高 ,其氧化分为两步单电子可逆过程 ,分子内的两个二茂铁基之间存在着较强的电子交流 ,电子传递主要是通过配体的骨架链进行的 ,观察到出现在 1 4 53cm- 1 处的νCC 伸缩强振动峰。而变形四面体钴配合物桥联双二茂铁体系的氧化为一步两电子过程 ,分子中的电子离域程度低 ,抑制了两个二茂铁基之间的电子交流 ,两个二茂铁基近乎等同。 相似文献