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61.
研究固态化学反应对合成化学、理论研究以及工业生产都有重要意义,南京大学忻新泉等人在室温或低温温度条件下固相配位反应的合成及机理研究方面做了许多有意义的工作[1,2],为使低温温度固相合成法最终走向应用作了积极贡献。由于固相配位反应的热效应难以直接测定,热化学... 相似文献
62.
Thermoanalytical, mass spectrometric and X-ray diffraction data were associated with a reliable assignation of the thermal
transformations of the coordination compound [Mn(urea)6](NO3)2·2H2O.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
63.
Hongsheng Wang Bingzheng Wang Sean-Thomas B. Lundin Hui Kong Bosheng Su Jian Wang 《Molecules (Basel, Switzerland)》2021,26(22)
To efficiently convert and utilize intermittent solar energy, a novel solar-driven ethanol steam reforming (ESR) system integrated with a membrane reactor is proposed. It has the potential to convert low-grade solar thermal energy into high energy level chemical energy. Driven by chemical potential, hydrogen permeation membranes (HPM) can separate the generated hydrogen and shift the ESR equilibrium forward to increase conversion and thermodynamic efficiency. The thermodynamic and environmental performances are analyzed via numerical simulation under a reaction temperature range of 100–400 °C with permeate pressures of 0.01–0.75 bar. The highest theoretical conversion rate is 98.3% at 100 °C and 0.01 bar, while the highest first-law efficiency, solar-to-fuel efficiency, and exergy efficiency are 82.3%, 45.3%, and 70.4% at 215 °C and 0.20 bar. The standard coal saving rate (SCSR) and carbon dioxide reduction rate (CDRR) are maximums of 101 g·m−2·h−1 and 247 g·m−2·h−1 at 200 °C and 0.20 bar with a hydrogen generation rate of 22.4 mol·m−2·h−1. This study illustrates the feasibility of solar-driven ESR integrated with a membrane reactor and distinguishes a novel approach for distributed hydrogen generation and solar energy utilization and upgradation. 相似文献
64.
65.
Xiao‐Jun Li Chun‐Ping Li Ju‐Cai Yang Abraham F. Jalbout 《International journal of quantum chemistry》2009,109(6):1283-1301
The hydrogenated silicon clusters structures, electron affinities, and dissociation energies of the Si6Hn/Si6H (n = 3?14) species have been systematically investigated by means of three density functional theory (DFT) methods. The basis set used in this work is of double‐ζ plus polarization quality with additional diffuse s‐ and p‐type functions, denoted DZP++. The geometries are fully optimized with each DFT method independently. Three different types of energy separations presented in this work are the adiabatic electron affinity (EAad), the vertical electron affinity (EAvert), and the vertical detachment energy (VDE). The first Si? H dissociation energies De (Si6Hn→ Si6Hn?1+H) for the neutral Si6Hn and De (Si6H→Si6H+H) for the anionic Si6H species have also been reported. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 相似文献
66.
Pablo A. Denis 《Molecular physics》2014,112(8):1167-1173
By means of coupled cluster theory and correlation consistent basis sets we investigated the thermochemistry of dimethyl sulphide (DMS), dimethyl disulphide (DMDS) and four closely related sulphur-containing molecules: CH3SS, CH3S, CH3SH and CH3CH2SH. For the four closed-shell molecules studied, their enthalpies of formation (EOFs) were derived using bomb calorimetry. We found that the deviation of the EOF with respect to experiment was 0.96, 0.65, 1.24 and 1.29 kcal/mol, for CH3SH, CH3CH2SH, DMS and DMDS, respectively, when ΔHf,0 = 65.6 kcal/mol was utilised (JANAF value). However, if the recently proposed ΔHf,0 = 66.2 kcal/mol was used to estimate EOF, the errors dropped to 0.36, 0.05, 0.64 and 0.09 kcal/mol, respectively. In contrast, for the CH3SS radical, a better agreement with experiment was obtained if the 65.6 kcal/mol value was used. To compare with experiment avoiding the problem of the ΔHf,0 (S), we determined the CH3–S and CH3–SS bond dissociation energies (BDEs) in CH3S and CH3SS. At the coupled cluster with singles doubles and perturbative triples correction level of theory, these values are 48.0 and 71.4 kcal/mol, respectively. The latter BDEs are 1.5 and 1.2 kcal/mol larger than the experimental values. The agreement can be considered to be acceptable if we take into consideration that these two radicals present important challenges when determining their EOFs. It is our hope that this work stimulates new studies which help elucidate the problem of the EOF of atomic sulphur. 相似文献
67.
A new hydrated lithium borate, Li4[B8O13(OH)2]·3H2O, has been hydrothermally synthesized and characterized by single crystal X‐ray diffraction, FT‐IR spectroscopy, simultaneous TGA‐DTA and chemical analysis. It crystallizes in the triclinic, space group , a=8.4578(5) Å, b=8.7877(5) Å, c=10.8058(7) Å, α=87.740(3)°, β=71.819(3)°, γ=61.569(3)°, Z=2, V=665.26(7) Å3, Dc=2.043 g/cm3. Its crystal structure features polyborate anionic layers with the larger odd 13‐membered boron rings constructed by [B8O13(OH)2]4? FBBs. Through designing the thermochemical cycle, the standard molar enthalpy of formation of this borate was determined to be ?(7953.8±6.6) kJ·mol?1 by using a heat conduction microcalorimeter. 相似文献
68.
The vibrational properties of barium peroxide, BaO2, were investigated by phonon calculations based on density‐functional theory and the ab initio force‐constant method. In order to reproduce the correct wavenumber of the peroxide vibration at finite temperatures, its volume dependence together with the calculated volume expansion was taken into account. Using this approximation we found a quantitative agreement of the calculated value with experimental data observed by Raman spectroscopy. 相似文献
69.
钾芒硝是一种成因复杂的复盐[1~ 3 ] ,并且由于钾芒硝K3 Na(SO4 ) 2 与硫酸钾石 [K3 Na(SO4 ) 2 或Na2 SO4 ·3K2 SO4 ]的化学组成相同 ,未能确定二者是否属于同一种复盐[4 ,5] 。我们合成了复盐K3 Na(SO4 )2[3 ] ,用溶解量热法测定了K3 Na(SO4 )2 和反应物 [Na2 SO4 (s) +K2 SO4 (s) ]的溶解焓 ,通过设计热化学循环计算出复盐的标准生成焓 ,为我们了解钾芒硝和硫酸钾石是否为同一复盐 ,并为进一步研究其成因和组成提供参考。1 实验部分1 1 试剂与仪器K2 SO4 (s)和Na2 SO4 (s)为A .R .… 相似文献
70.
M. K. Rotich B. D. Glass M. E. Brown 《Journal of Thermal Analysis and Calorimetry》2001,64(2):681-688
The thermal behaviour of various substituted aminobenzoic acids(3-aminobenzoic acid (3-ABA), 4-aminobenzoic acid (4-ABA),
3-aminosalicylic acid(3-ASA), 4-aminosalicylic acid (4-ASA), and 5-aminosalicylic acid (5-ASA), as well as the‘parent’ benzoic
acid (BA) and salicylic acid (SA) as reference substances, and possible decomposition products: 2-aminophenol (2-AP), 3-aminophenol
(3-AP) and 4-aminophenol(4-AP) in the solid state has been examined.
The various sets of isomers studied showed considerable and interesting differences. Most sublimed well before melting, generally
with an increasing rate of mass loss beyond their very different melting points. The differences in behaviour of 4-ASA and
5-ASA were the most remarkable, with 5-ASA being far more stable and apparently not decarboxylating readily, while 4-ASA sublimed
at temperatures below the melting point, becoming less stable and decarboxylating in the liquid form.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献