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81.
Reshma Khemchandani Nishil Gupta Arpit Chaudhary Suresh Chandra 《Optimization Letters》2013,7(3):575-592
In this paper, we develop optimal trading strategies for a risk averse investor by minimizing the expected cost and the risk of execution. Here we consider a law of motion for price which uses a convex combination of temporary and permanent market impact. In the special case of unconstrained problem for a risk neutral investor, we obtain a closed form solution for optimal trading strategies by using dynamic programming. For a general problem, we use a quadratic programming approach to get approximate dynamic optimal trading strategies. Further, numerical examples of optimal execution strategies are provided for illustration purposes. 相似文献
82.
Umadevi M Vanelle P Terme T Rajkumar BJ Ramakrishnan V 《Journal of fluorescence》2008,18(6):1139-1149
Solvatochromic and preferential solvation of 1,4-dihydroxy-2,3-dimethyl-9,10-anthraquinone (DHDMAQ) have been investigated
using optical absorption and fluorescence emission techniques. Optical absorption spectra of DHDMAQ in different solvents
show the intra molecular charge transfer band in the region 400–550nm. The observed blue shift with solvent polarity indicates
the delocalisation of the excited state, owing to reduction in quasiaromaticity of the chelate rings formed by intra molecular
hydrogen bonds, due to electrostatic or hydrogen bonding interaction. This is also confirmed by the observed low oscillator
strength and the transition dipole moment. The observed quantum yield of DHDMAQ in different solvents is due to the inter
molecular hydrogen bond in the excited state in addition to the intra molecular hydrogen bond. It also reveals from the low
oscillator strength, which indicates that the radiative decay is low. Excited state dipole moment of DHDMAQ is calculated
by solvatochromic data
and it shows a lower value than ground state dipole moment. The preferential solvation parameter shows that in dimethyl formamide
(DMF) + ethanol mixture, the DHDMAQ is preferentially solvated by ethanol in DMF rich region and by DMF in ethanol rich region.
In the case of DMF + dichloromethane mixture DHDMAQ is preferentially solvated by DMF. 相似文献
83.
Facile and efficient synthesis of sulfoxide esters using menthols as chiral auxiliary is described. Phenylthio/benzylthio/naphthylthioacetic esters act as an efficient substrate for chiral sulfoxides via oxidation in one step. The structural and stereochemical aspects of target product were established on the basis of various spectroscopic studies, namely FT-IR, NMR (1H NMR and 13C NMR) and elemental analysis. This method is simple, fast, convenient and very efficient. 相似文献
84.
85.
Reshma Jose Dr. Srinivasu Kancharlapalli Dr. Tapan K. Ghanty Prof. Sourav Pal Prof. Gopalan Rajaraman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(18):e202104526
The coordinatively unsaturated chromium(II)-based Cr3[(Cr4Cl)3(BTT)8]2 (Cr−BTT; BTT3−=1,3,5-benzenetristetrazolate) metal–organic framework (MOF) has been shown to exhibit exceptional selectivity towards adsorption of O2 over N2/H2. Using periodic density functional theory (DFT) calculations, we attempted to decipher the origin of this puzzling selectivity. By computing and analyzing the magnetic exchange coupling, binding energies, the partial density of states (pDOS), and adsorption isotherms for the pristine and gas-bound MOFs [(Cr4(X)4Cl)3(BTT)8]3− (X=O2, N2, and H2), we unequivocally established the role of spin states and spin coupling in controlling the gas selectivity. The computed geometries and gas adsorption isotherms are consistent with the earlier experiments. The binding of O2 to the MOF follows an electron-transfer mechanism resulting in a CrIII superoxo species (O2.−) with a very strong antiferromagnetic coupling between the two centers, whereas N2/H2 are found to weakly interact with the metal center and hence only slightly perturb the associated coupling constants. Although the gas-bound and unbound MOFs have an S=0 ground state (GS), the nature of spin the configurations and the associated magnetic exchanges are dramatically different. The binding energy and the number of oxygen molecules that can favorably bind to the Cr center were found to vary with respect to the spin state, with a significant energy margin (47.6 kJ mol−1). This study offers a hitherto unknown strategy of using spin state/spin couplings to control gas adsorption selectivity in MOFs. 相似文献
86.
Sasirekha V Umadevi M Ramakrishnan V 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(1):148-155
Preferential solvation of a solvatochromic probe has been studied in binary mixtures comprising of a non-protic and a protic solvent. The non-protic solvents employed are carbon tetrachloride (CCl(4)), acetonitrile (AcN) and N,N-dimethyl formamide (DMF) and the protic solvents are methanol (MeOH) and ethanol (EtOH). The probe molecule exhibits different spectroscopic characteristics depending upon the properties of the solubilizing media. The observed spectral features provide an indication of the microenvironment immediately surrounding the probe. Solvatochromic shifts of the ground and excited states of the probe were analysed by monitoring the charge transfer absorption band and the fluorescence emission spectra in terms of the solute-solvent and solvent-solvent interactions. Fluorescence emission spectra show the dual emission due to excited state proton transfer nature of the probe molecule. The effect of solvent and the excitation energy on dual emission are also studied. The observed magnitude of the Stokes shift in the above solvents has been used to deduce experimentally the dipole moment ratio of the probe molecule for the excited state to the ground state. The dipole moment of excited state is higher than the ground state. 相似文献
87.
Herein, we report a detailed periodic DFT investigation of Mn(II)-based [(Mn4Cl)3(BTT)8]3− (BTT3−=1,3,5-benzenetristetrazolate) metal-organic framework (MOF) to explore various hydrogen binding pockets, nature of MOF…H2 interactions, magnetic coupling and, H2 uptake capacity. Earlier experiments found an uptake capacity of 6.9 wt % of H2, with the heat of adsorption estimated to be ∼10 kJ/mol, which is one among the highest for any MOFs reported. Our calculations unveil different binding sites with computed binding energy varying from −6 to −15 kJ/mol. The binding of H2 at the Mn2+ site is found to be the strongest (site I), with H2 found to bind Mn2+ ion in a η2 fashion with a distance of 2.27 Å and binding energy of −15.4 kJ/mol. The bonding analysis performed using NBO and AIM reveal a strong donation of σ (H2) to the dz2 orbital of the Mn2+ ion responsible for such large binding energy. The other binding pockets, such as −Cl (site II) and BTT ligands (site III and IV) were found to be weaker, with the binding energy decreasing in the order I>II>III>IV. The average binding energy computed for these four sites put together is 9.6 kJ/mol, which is in excellent agreement with the experimental value of ∼10 kJ/mol. We have expanded our calculations to compute binding energy for multiple sites simultaneously, and in this model, the binding energy per site was found to decrease as we increased the number of H2 molecules suggesting electronic and steric factors controlling the overall uptake capacity. The calculated adsorption isotherm using the GCMC method reproduces the experimental observations. Further, the magnetic coupling computed for the unbound MOF reveals moderate ferromagnetic and strong antiferromagnetic coupling within the tetrameric {Mn4} unit leading to a three-up-one-down spin configuration as the ground state. These were then coupled ferromagnetically to other tetrameric units in the MOF network. The magnetic coupling was found to alter only marginally upon gas binding, suggesting that both exchange interaction and the spin-states are unlikely to play a role in the H2 uptake. This is contrary to the O2 uptake studied lately, where strong dependence on exchange-coupling/spin state was witnessed, suggesting exchange-coupling/magnetic field dependent binding as a viable route for gas separation. 相似文献
88.
Manjunatha Bhat G. K. Nagaraja Reshma Kayarmar S. V. Raghavendra K. P. Rajesh H. Manjunatha 《Research on Chemical Intermediates》2016,42(12):7771-7792
A new series of 2-(3-chloro-2-fluorophenyl)-5-aryl-1,3,4-oxadiazole (3a–j) and 2-(aryl sulfanyl)-5-(3-chloro-2-fluorophenyl)-1,3,4-oxadiazole (5a–e) were synthesized via a multistep reaction from 3-chloro-2-fluoro benzoic acid. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR, mass spectral data and elemental analysis. They were also screened for their in vivo anti-convulsant and anti-inflammatory activities. Some of them exhibited significant biological activities and were well supported by in silico molecular docking studies for the inhibition of cyclooxygenase-2 (PDB ID: 1CX2) and voltage-gated sodium channels (PDB ID: 4F4L) comparable with the standard drugs. Thus, they were believed to be good inhibitors of cyclooxygenase-2 (PDB ID: 1CX2) and voltage-gated sodium channels (PDB ID: 4F4L). 相似文献
89.
In this paper, the error estimation and adaptive strategy developed for the linear elastodynamic problem under transient dynamic loading based on the Z–Z criterion is utilized for 2D and plate bending problems. An automatic mesh generator based on “growth meshing” is utilized effectively for adaptive mesh refinement. Optimal meshes are obtained iteratively corresponding to the prescribed domain discretization error limit and for a chosen number of basis modes satisfying modal truncation errors. Numerous examples show the effectiveness of the integrated approach in achieving the target accuracy in finite element transient dynamic analysis. 相似文献
90.
Palanisamy Shanmugasundaram Periyasamy Murugan Vayalakkavoor T. Ramakrishnan Narayanan Srividya Perumal Ramamurthy 《Heteroatom Chemistry》1996,7(1):17-22
Synthesis of 9-alkyl, 10-alkyl, 9,10-dialkyl, and 10-aryl-3,4,6,7,9,10-hexahydro-1,8(2H,5H)acridinedione (2a–r) are described as a new class of laser dyes. Reactions of diamines with methylene bis(cyclohexane-1,3-dione) yielded the respective bisacridinediones (3a–e). These dyes lase around 478–494 nm and are compared with the standard dye coumarin-102. © 1996 John Wiley & Sons, Inc. 相似文献