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131.
132.
We prove the Strong Maximum Principle (SMP) under suitable assumptions for a class of quasilinear parabolic problems with the p -Laplacian, p>1, on bounded cylindrical domains of RN+1, with nonnegative initial–boundary conditions and λ≤0, and we give some counterexamples to the SMP if some of our assumptions are violated. We show that the Hopf Maximum Principle holds for 1<p<2, and give a counterexample to it for p>2. Also the Weak Maximum Principle for λ≤λ1 is established. 相似文献
∂tu−Δpu−λ|u|p−2u≥0,
133.
Accurate calculations for the ground state of the molecular ions He3+2 and HeH2+ placed in a strong magnetic field B?102 a.u. (≈2.35×1011 G) using the Lagrange-mesh method are presented. The Born–Oppenheimer approximation of zero order (infinitely massive centers) and the parallel configuration (molecular axis parallel to the magnetic field) are considered. Total energies are found with 9–10 s.d. The obtained results show that the molecular ions He3+2 and HeH2+ exist at B>100 a.u. and B>1000 a.u., respectively, as predicted in Turbiner and López Vieyra (2007) [1] while a saddle point in the potential curve appears for the first time at B∼80 a.u. and B∼740 a.u., respectively. 相似文献
134.
Density-functional theory (DFT) and model Hamiltonians are conceptually distinct approaches to the many-particle problem, which can be developed and applied independently. In practice, however, there are multiple connections between the two. This review focuses on these connections. After some background and introductory material on DFT and on model Hamiltonians, we describe four distinct, but complementary, connections between the two approaches: (i) the use of DFT as input for model Hamiltonians, in order to calculate model parameters such as the Hubbard U and the Heisenberg J. (ii) The use of model Hamiltonians as input for DFT, as in the LDA + U functional. (iii) The use of model Hamiltonians as theoretical laboratories to study aspects of DFT. (iv) The use of special formulations of DFT as computational tools for studying spatially inhomogeneous model Hamiltonians. We mostly focus on this fourth combination, model DFT, and illustrate it for the Hubbard model and the Heisenberg model. Other models that have been treated with DFT, such as the PPP model, the Gaudin–Yang δ-gas model, the XXZ chain, variations of the Anderson and Kondo models and Hooke’s atom are also briefly considered. Representative applications of model DFT to electrons in crystal lattices, atoms in optical lattices, entanglement measures, dynamics and transport are described. 相似文献
135.
Huifang Miao 《Discrete Applied Mathematics》2006,154(11):1606-1614
For two vertices u and v in a strong digraph D, the strong distance sd(u,v) between u and v is the minimum size (the number of arcs) of a strong sub-digraph of D containing u and v. For a vertex v of D, the strong eccentricity se(v) is the strong distance between v and a vertex farthest from v. The strong radius srad(D) (resp. strong diameter sdiam(D)) is the minimum (resp. maximum) strong eccentricity among the vertices of D. The lower (resp. upper) orientable strong radius srad(G) (resp. SRAD(G)) of a graph G is the minimum (resp. maximum) strong radius over all strong orientations of G. The lower (resp. upper) orientable strong diameter sdiam(G) (resp. SDIAM(G)) of a graph G is the minimum (resp. maximum) strong diameter over all strong orientations of G. In this paper, we determine the lower orientable strong radius and diameter of complete k-partite graphs, and give the upper orientable strong diameter and the bounds on the upper orientable strong radius of complete k-partite graphs. We also find an error about the lower orientable strong diameter of complete bipartite graph Km,n given in [Y.-L. Lai, F.-H. Chiang, C.-H. Lin, T.-C. Yu, Strong distance of complete bipartite graphs, The 19th Workshop on Combinatorial Mathematics and Computation Theory, 2002, pp. 12-16], and give a rigorous proof of a revised conclusion about sdiam(Km,n). 相似文献
136.
J. Nawrocki 《Chromatographia》1987,23(10):722-726
Summary A simple gas chromatographic method is presented for the determination of the quantity of the strongest adsorption sites on
an adsorbent's surface. The method consists of the blockage of the sites with quasi-irreversibly adsorbed, known amount of
a strongly interacting compound and subsequent measuring of the retention of a hydrocarbon during the presence of the blocking
compound in the column. Heterogeneity of chromatographic grade silicas is investigated with this method. 相似文献
137.
本文讨论了均匀分布族{R(0,θ),θ>0}中参数θ的矩估计及最大似然估计的效率及相合性,结果表明θ修正后的最大似然估计要优于θ的矩估计。 相似文献
138.
139.
周勇 《数学物理学报(A辑)》1997,17(3):245-254
文中证明了核邻型的光滑条件分位过程的强逼近,获得了其一致逼近速度.并由此结果推导出了光滑条件分位估计的渐近正态性、弱收敛和对数律等深刻结果. 相似文献
140.
本文首先给出了一个右连续上鞅的SD提升,在引进S-上鞅和强S-上鞅概念之后,研究了一一致可积上鞅与S-上鞅,类上鞅与强S-上鞅之间的关系,并得到了S-上鞅与强S-上鞅的许多性质,作为其直接结果,给出了类上鞅的Doob-MNeyer分解。 相似文献