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51.
Application of Löwdin's canonical orthogonalization method to the Slater‐type orbital configuration‐interaction basis set 下载免费PDF全文
We apply Löwdin's canonical orthogonalization method to investigate the linearly dependent problem arising from the variational calculation of atomic systems using Slater‐type orbital configuration‐interaction (STO‐CI) basis functions. With a specific arithmetic precision used in numerical computations, the nonorthogonal STO‐CI basis is easily linearly dependent when the number of basis functions is sufficiently large. We show that Löwdin's canonical orthogonalization method can successfully overcome such problem and simultaneously reduce the dimension of basis set. This is illustrated first through an S‐wave model He atom, and then the real two‐electron atoms in both the ground and excited states. In all of these calculations, the variational bound state energies of the two‐electron systems are obtained in reasonably high accuracy using over‐redundant STO‐CI bases, however, without using extended high‐precision technique. © 2015 Wiley Periodicals, Inc. 相似文献
52.
Periodica Mathematica Hungarica - We prove that the inequality $$\begin{aligned} \Gamma (x+1)\le \frac{x^2+\beta }{x+\beta } \end{aligned}$$ holds for all $$x\in [0,1]$$ , $$\beta \ge {\beta... 相似文献
53.
Y2O3:Eu3+ phosphor films have been developed by using the sol-gel process. Comprehensive characterization methods such as Photoluminescent (PL) spectroscopy, X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy were used to characterize the Y2O3:Eu3+ phosphor films. In this experiment, the XRD profiles show that the Y2O3:Eu3+ phosphor films crystallization temperature and optimum annealing temperature occur at about 650 and 750 °C, respectively. The optimum dopant concentration is 12 mol% Eu3+ and the critical transfer distance (Rc) among Eu3+ ions is calculated to be about 0.84 nm. Vacuum environment is more efficient than oxygen and nitrogen to eliminate the OH content and hence yields higher luminescent phosphor films. The PL emission intensity of Y2O3:Eu3+ phosphor films is also dependent on the annealing time. It was found that the H2O impurities were effectively eliminated after annealing time of 25 s at 750 °C in vacuum environment. From the experiment results, the schematic energy band diagram of Y2O3:Eu3+ phosphor films is constructed. 相似文献
54.
A study of the relationship between competitiveness and technological innovation capability based on DEA models 总被引:12,自引:0,他引:12
Jian Cheng Guan Richard C.M. Yam Chiu Kam Mok Ning Ma 《European Journal of Operational Research》2006,170(3):971-986
Researchers and managers have been searching for appropriate methods to explore the relationship between technological innovation capability and competitiveness in recent years. This study attempts to find a systematic quantitative methodology to tackle this problem. In a recent survey covering 182 industrial innovative firms in China, the traditional data envelopment analysis (DEA) model was employed to analyze the data collected. The research results show that only 16% of the enterprises operate on the best-practice frontier and there are some inconsistencies between organizational innovation capability and competitiveness in many enterprises. Decreasing returns to scale were found among about 70% of the inefficient enterprises and increasing returns to scale were found among the remaining 30% of the inefficient enterprises. Thus the internal innovation harmonizing process in these enterprises is considerably inefficient. Based on the restricted ranges of the input/output factors, a multi-objective DEA projection model has also been developed in this study to provide a benchmark for auditing competitiveness. Research results further indicate that there is still much room for enterprises to improve competitiveness in situations of confining score ranges of technological innovation capability and competitiveness. 相似文献
55.
We present relativistic three-body calculations for the real part of the π-4He scattering length Re a. Nucleon binding, exclusion principle and Fermi motion are all included in a very careful manner. Because of our careful evaluation of the single-scattering process the remaining discrepancies with the experimental data can be attributed to higher-order mechanisms involving more than one nucleon. In particular for the πA S-wave interaction at threshold, one expects that these higher-order contributions arise largely from the absorption effect. We have performed our calculations for four current models of the input πN t-matrix. Using a πN t-matrix which reproduces the low energy πN phase shifts correctly leads to Re aabs -Im aabs, if we attribute the discrepancy of the calculated value with the accurately determined empirical value of Re a to pion absorption. We determine the strength parameter B0 in a p2 optical potential term from an adjustment to the π-4He scattering length. Finally some cross sections are calculated for Tlabπ = 10 MeV and Tlabπ = 15 MeV. 相似文献
56.
T. T. Kam S. S. Chatterjee K. E. Heusler 《Applied Physics A: Materials Science & Processing》1984,35(4):219-226
Etch pit densities on iron (110) surfaces in sulphuric acid grow linearly with the interfacial hydrogen activity in excess of a critical activity. The hydrogen activity is approximately proportional to the square root of the cathodic current density. At constant cathodic current density the etch pit density increases with temperature and decreases with external stress. Dislocations at which the excess etch pits form penetrate into the iron at a rate proportional to the hydrogen activity and the square root of time. Effects of prior hydrogen deposition on the shape of etch pits are seen at depths greater than the penetration depth of hydrogen generated dislocations. Changes of etch pit shape similar to those produced by hydrogen are also found when external stress is applied.The results are compared to Prussin's theory in which the assumption is made that stresses accompanying diffusion of an impurity are fully relieved by plastic deformation and formation of dislocations for stresses exceeding a critical stress. While some of the predictions of the theory are met by the experiments, the dislocations penetrate into the iron much slower than diffusion of hydrogen, since dislocations cannot move fast enough, i.e. stresses are not fully relieved. 相似文献
57.
58.
Dobrev PI Havlícek L Vagner M Malbeck J Kamínek M 《Journal of chromatography. A》2005,1075(1-2):159-166
A method for separation and purification of plant hormones auxin and abscisic acid based on mixed mode reversed-phase anion-exchange solid phase extraction and two-dimensional HPLC was developed. Two-dimensional HPLC in "heart cutting" mode was very efficient in the purification of these two hormones. Its purification power is high enough to allow reliable on-line quantification of both hormones even with non-selective detectors. 相似文献
59.
A multilevel finite element method in space‐time for the two‐dimensional nonstationary Navier‐Stokes problem is considered. The method is a multi‐scale method in which the fully nonlinear Navier‐Stokes problem is only solved on a single coarsest space‐time mesh; subsequent approximations are generated on a succession of refined space‐time meshes by solving a linearized Navier‐Stokes problem about the solution on the previous level. The a priori estimates and error analysis are also presented for the J‐level finite element method. We demonstrate theoretically that for an appropriate choice of space and time mesh widths: hj ~ h, kj ~ k, j = 2, …, J, the J‐level finite element method in space‐time provides the same accuracy as the one‐level method in space‐time in which the fully nonlinear Navier‐Stokes problem is solved on a final finest space‐time mesh. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005 相似文献
60.
Addition of two equivalent amounts of appropriate primary amine to the carbon-carbon double bonds of 1, 2-dimaleic acid hydrazine(I) in suitable solvents at room temperature of under reflux provided a number of 1, 2-bis(N-substituted β-aspartyl) hydrazines (IIa-k) in satisfactory yields. In some cases of this reaction, the mono-aminated intermediates (IIIa-c) were also isolated. 相似文献