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51.
Various types of data become available at different stages of a reservoir’s life. The production data are integrated into the flow simulation models through a process referred to as history matching. The history-matching process is iterative, and it usually involves a large number of simulation runs. Hence, this process requires significant computational time. In most history-matching methods, the initial geological assumptions in the reservoir model are destroyed or significantly altered in the process. Furthermore, they do not account for the information obtained during the previous trials, and lack learning from the previous failures. In this paper, we introduce a new methodology that maintains the geological realism. The candidate realizations are selected through a learning-based history-matching (LHM) algorithm by which all the previously successful patterns are preserved and used to assist the construction of the next realizations. The various pieces of matching regions are assembled together to make a pool of the successful candidates. Such regions are then utilized for making an auxiliary dataset in a multiscale framework by which the next model is generated. To prevent from trapping in local minima, ideas from the genetic algorithm is adapted. The LHM algorithm can be applied to both categorical and continuous distributions. The LHM provides a conditional map by which the new production data are immediately incorporated into the existing reservoir models. We apply the LHM algorithm to various 2D and 3D examples with very complex binary and continuous properties. The algorithm is shown to produce history-matched models with significantly smaller CPU times.  相似文献   
52.
It is shown that the countably infinite dimensional pointed vector space (the vector space equipped with a constant) over a finite field has infinitely many first order definable reducts. This implies that the countable homogeneous Boolean-algebra has infinitely many reducts.  相似文献   
53.
Metal-free electrocatalysts for oxygen reduction reaction (ORR) are key to the development of efficient, durable, and low-cost alternatives to noble-metal-based electrocatalysts in fuel cell cathodes. In recent years, many efforts are directed to the metal-free catalyst based on heteroatom-doped graphene. In this work, we demonstrate that the graphene surface can be converted into the catalyst for the oxygen reduction by chemical functionalization. In this context, we first synthesized malononitrile-functionalized graphene oxide. Amidoximation of nitrile group and reduction in graphene oxide were then carried out by hydroxylamine in one step. The electrochemical behavior of functionalized graphene-modified electrode for the reduction in oxygen was studied. The results showed that the electrocatalyst fabricated by this method exhibited striking catalytic activities in alkaline solution. In alkaline solution, this catalyst showed a competitive activity to the commercial Pt catalyst via four-electron transfer pathway with better ORR selectivity and stability. In addition, this metal-free electrocatalyst exhibited tolerance to methanol crossover effect. Based on its outstanding performance, this functionalized graphene electrocatalyst showed the promising prospect of a metal-free catalyst for fuel cell with much lower cost than currently used Pt/C catalyst.  相似文献   
54.
55.
In this paper, we prove explicit formulas for all Willmore surfaces of revolution and demonstrate their use in the discussion of the associated Dirichlet boundary value problems. It is shown by an explicit example that symmetric Dirichlet boundary conditions do in general not entail the symmetry of the surface. In addition, we prove a symmetry result for a subclass of Willmore surfaces satisfying symmetric Dirichlet boundary data.  相似文献   
56.
We study the internal stabilization of the higher order nonlinear Schrödinger equation with constant coefficients. Combining multiplier techniques, a fixed point argument and nonlinear interpolation theory, we can obtain the well-posedness. Then, applying compactness arguments and a unique continuation property, we prove that the solution of the higher-order nonlinear Schrödinger equation with a damping term decays exponentially.  相似文献   
57.
Molecular clips hold the potential of self-association and the ability to form host–guest complexes. Here we describe the synthesis of a 1,2-dimethoxyphenyl terminated glycoluril molecular clip (2) that binds with smaller solvent molecules by π?H–C and C=O?H–O non-covalent interactions. We obtained single crystals of 2 and 2 + CH2Cl2, CH3OH, CH3CN, and DMF solvents complexed within the clip. These solvents always form two π?H–C interactions between the aromatic rings in the clip, and CH3OH formed an additional C=O?H–O hydrogen bond with the glycoluril carbonyl group. Based on single crystal data we found that π?H–C interactions of 2 + CH2Cl2 are stronger than 2 + CH3CN and 2?+?DMF, due to the presence of stronger electron withdrawing groups in CH2Cl2, which lead to a decrease in dihedral angle of two glycoluril aromatic planes. We also investigated the non-covalent interaction energies of these solvent molecules with 2 using computational methods.

Graphical Abstract

Several solvent adducts of a glycoluril derivative have been isolated and characterized by single crystal X-ray diffraction, revealing two common pi?H–C non-covalent bonds within the molecular clip.
  相似文献   
58.
59.
Flat plates, both single and in tandem or side by side arrangement, are widely used in many engineering applications. Despite vast investigations of the flow structures and wakes downstream of these bluff bodies, this unsteady phenomenon yet remains a fundamental issue in many industrial applications. This paper reviews the state of the art concerning the flow over flat plates in different arrangements focusing on plates normal to the flow. Turbulent wake regions are discussed for the flat plates in side by side or tandem arrangement. Numerical studies are reviewed with emphasis on the realized turbulent models. The effect of the chosen turbulence model on the prediction of the wake region is discussed.  相似文献   
60.
Among the theories of neural information coding, the neural energy coding is more accessible to global coding features than traditional neural encoding. According to the shortcomings existing in the neuronal energy model, that is, the non-smooth nature of the energy curve, we proposed an improved neuronal energy model in this paper. The modified energy model is a good choice for establishment of the global model of brain function. And it is also the basis of energy calculation for functional cognitive neural networks in the future.  相似文献   
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