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91.
H. Altenbach V.A. Eremeyev 《ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik》2008,88(5):332-341
Considering the viscoelastic behavior of polymer foams, a new plate theory based on the direct approach is introduced and applied to plates composed of functionally graded materials (FGM). The governing two‐dimensional equations are formulated for a deformable surface and the stiffness parameters are identified for the linear viscoelastic isotropic material behavior. It is assumed that the material properties are changing in thickness direction. Solving the plate bending problem of the global mechanical analysis, it will be demonstrated that in some cases, the results significantly differ from the results based on the classical Kirchhoff‐type theory. 相似文献
92.
This paper presents a new approach for the detection and treatment of colloidal particle collisions. It has been developed in the framework of Lagrangian approaches where a large number of particles is explicitly tracked. The key idea is to account for the continuous trajectories of both colliding partners during a time step that is not restricted. Unlike classical approaches which consider only the distances between a pair of particles at the beginning and at the end of each time step (or assume straight-line motion in between), we model the whole relative, and possibly diffusive, trajectory. The collision event is dealt with using the probability that the relative distance reaches a minimum threshold (equal to the sum of the two particle radii). In that sense, the present paper builds on the idea of a previous work. However, in this first work, the collision event was simulated with a simplified scheme where one of the collision partners was removed and re-inserted randomly within the simulation domain. Though usually applied, this treatment is limited to homogeneous situations. Here, an extension of the stochastic model is proposed to treat more rigorously the collision event via a suitable evaluation of the time and spatial location of the collision and an adequate calculation of subsequent particle motion. The resulting collision kernels are successfully compared to theoretical predictions in the case of particle diffusive motion. With these promising results, the feasibility of simulating the collisional regime over a whole range of particle sizes (even nanoscopic) and time steps (from a ballistic to a purely diffusive regime) with a numerical method of reasonable computational cost has been confirmed. The present approach thus appears as a good candidate for the simulation of the agglomeration phenomenon between particles also in complex non-homogeneous flows. 相似文献
93.
Raman scattering has been used to study the vibrational spectra of GaSexS1‐x layered mixed crystals at 10 K. We report the frequency dependencies of different modes on composition x, with particular emphasis on A′1(2) (A1g1) and A′1(4) (A1g2) intralayer compressional modes having low dispersion in the Brillouin zone. The appearance of additional bands is attributed to multimode behavior typically exhibited by mixed crystals of anisotropic compounds. 相似文献
94.
Tayebeh Hosseinnejad 《Molecular Crystals and Liquid Crystals》2014,605(1):89-102
In this research, we have concentrated on the survey of ability of density functional methods and also modern semi-empirical approaches to reproduce the crystal structure of a binuclear silyl nickel complex and a trinuclear palladium silyl complex. In the structural analysis of the aforesaid nickel and palladium complexes, we have also interested to investigate the possibility of Si-Si bond formation between SiH2 and μ-SiH moieties from the structural and electronic viewpoints. Comparison of our calculated structural parameters of aforementioned complexes with the available X-ray crystallographical data reveals that both functionals (B3LYP and M062X) can well reproduce X-ray structure of the complex with a near accuracy while the PM6-D2 semi-empirical calculated values are not in a reliable agreement with the crystallographical data. In the next step, we assessed the nature of interactions between palladium and nickel metal ions with silyl ligands via Quantum Theory of Atoms in Molecule (QTAIM) computations. Furthermore, we have analyzed the possibility of Si-Si bond formation in the aforementioned complexes by means of topological electronic indices. Strictly speaking, QTAIM calculations have been performed to explore the electronic density, its laplacian and electronic energy density at some key bond critical points to interpret the structural features of aforesaid complexes from the electronic point of view. 相似文献
95.
Martin Schreyer Liangfeng Guo Martin Tjahjono Marc Garland 《Journal of Applied Crystallography》2011,44(1):17-24
Three different approaches for a total quantitative phase analysis of organic mixture data were presented and subsequently tested on a set of ten ternary powder mixtures consisting of α‐glycine, α‐lactose monohydrate and paracetamol form I. In each of these methods, an external standard was used (in the present study, diamond) to determine the diffractometer constant, which was employed to place the crystalline intensities of all other samples on an absolute scale. In Method A, pure component diffractograms were also measured. In Methods B and C, no pure component diffractograms were used. Using Methods A–C, both the absolute crystalline compositions and all the amorphous compositions of the samples were determined. These methods outperform the quantitative phase analysis provided by conventional Rietveld analysis. An average error of less than 0.5 wt% was achieved with the present approaches, whereas the average error from conventional Rietveld analysis was ca 1.3 wt%. 相似文献
96.
Hiroshi Sakai Takashi Yamazaki Nobuya Machida Toshihiko Shigematsu Saburo Nasu 《Molecular Crystals and Liquid Crystals》2013,570(2):105-110
Abstract Mössbauer spectra of the FePS3-cobaltocene intercalation compound were measured in the temperature range of 300K to 10K. The spectra, distinct from those of pure FePS3, suggest the charge transfer from cobaltocene to Fe-S antibonding orbitals of the FePS3 host lattice. 相似文献
97.
An efficient geometric approach to refine anisotropic domain morphology in the double‐Voigt approach based on the variance‐slope apparent crystallite size was recently described. In this way, the Lorentzian part of the Voigt size contribution can be directly linked to an effective area‐ or surface‐weighted morphology. The size contribution in the Voigt approach is, however, rarely pure Lorentzian. In this article, the previously considered models are extended for the Gaussian part of the size broadening, also taking into account size distributions. The limits of the validity of the Voigt approach are also discussed. 相似文献
98.
M. Dilmi H. Benseridi & A. Saadallah 《advances in applied mathematics and mechanics.》2014,6(6):797-810
In this paper we prove first the existence and uniqueness results for the weak solution, to thestationary equations for Bingham fluid in a three dimensional bounded domainwith Fourier and Tresca boundary condition; then we study the asymptoticanalysis when one dimension of the fluid domain tends to zero. The strongconvergence of the velocity is proved, and a specific Reynolds limit equationand the limit of Tresca free boundary conditions are obtained. 相似文献
99.
Khazangul A. Ibrahimova Abdulsaid A. Azizov Ofeliya O. Balayeva Rasim M. Alosmanov Sevinj C. Mammadyarova 《Mendeleev Communications》2021,31(1):100-103
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100.
T. Kyu G. C. Zhu Z. L. Zhou Y. Tajuddin S. Qutubuddin 《Journal of Polymer Science.Polymer Physics》1996,34(10):1769-1775
A novel in situ composite comprised of kaolin clay fillers and polyamide 6 (Nylon-6) was synthesized via a colloidal approach by suspending kaolin particles in aqueous caprolactam and then polymerizing the caprolactam under elevated temperature and pressure. This in situ polymerization technique enables the deposition of nylon molecules directly onto the filler surface. It offers a much larger contact surface area for the nylon molecules to interact with the filler particles and enhances filler/matrix interaction through polymer miscibility. The kaolin particles were shown to be uniformly dispersed in Nylon-6 matrix without appreciable agglomeration. In the highly clay-loaded composites such as the 50/50 kaolin/Nylon-6 in situ composite, the deposited nylon molecules probably form a coated layer on the filler particles. This kind of nylon coated fillers may be applied as a reinforcing entity to commercial Nylon-6 or −;66 by improving particle dispersion and melt processability. The 50/50 kaolin/Nylon-6 in situ composites have been used as a masterbatch for blending with commercial Nylon-6 and Nylon-66 to take advantage of their good properties and to reduce cost. Rheology and mechanical properties of the masterbatch/nylon composites have been investigated in comparison with those of the conventional melt-mixed composites. The improvement of rheological and mechanical properties of the in situ composites has been discussed in relation to the composite structure. © 1996 John Wiley & Sons, Inc. 相似文献