全文获取类型
收费全文 | 7080篇 |
免费 | 333篇 |
国内免费 | 410篇 |
专业分类
化学 | 934篇 |
晶体学 | 50篇 |
力学 | 238篇 |
综合类 | 61篇 |
数学 | 4830篇 |
物理学 | 1710篇 |
出版年
2023年 | 44篇 |
2022年 | 70篇 |
2021年 | 110篇 |
2020年 | 147篇 |
2019年 | 151篇 |
2018年 | 134篇 |
2017年 | 120篇 |
2016年 | 140篇 |
2015年 | 142篇 |
2014年 | 219篇 |
2013年 | 533篇 |
2012年 | 273篇 |
2011年 | 273篇 |
2010年 | 232篇 |
2009年 | 367篇 |
2008年 | 412篇 |
2007年 | 474篇 |
2006年 | 385篇 |
2005年 | 288篇 |
2004年 | 258篇 |
2003年 | 268篇 |
2002年 | 311篇 |
2001年 | 257篇 |
2000年 | 317篇 |
1999年 | 247篇 |
1998年 | 252篇 |
1997年 | 170篇 |
1996年 | 112篇 |
1995年 | 102篇 |
1994年 | 106篇 |
1993年 | 82篇 |
1992年 | 79篇 |
1991年 | 70篇 |
1990年 | 65篇 |
1989年 | 56篇 |
1988年 | 47篇 |
1987年 | 64篇 |
1986年 | 33篇 |
1985年 | 71篇 |
1984年 | 52篇 |
1983年 | 30篇 |
1982年 | 46篇 |
1981年 | 24篇 |
1980年 | 26篇 |
1979年 | 33篇 |
1978年 | 24篇 |
1977年 | 30篇 |
1976年 | 19篇 |
1974年 | 17篇 |
1973年 | 11篇 |
排序方式: 共有7823条查询结果,搜索用时 15 毫秒
41.
Contingent epiderivatives and set-valued optimization 总被引:24,自引:0,他引:24
In this paper we introduce the concept of the contingent epiderivative for a set-valued map which modifies a notion introduced by Aubin [2] as upper contingent derivative. It is shown that this kind of a derivative has important properties and is one possible generalization of directional derivatives in the single-valued convex case. For optimization problems with a set-valued objective function optimality conditions based on the concept of the contingent epiderivative are proved which are necessary and sufficient under suitable assumptions. 相似文献
42.
Matthew D. Bailey Steven M. Shechter Andrew J. Schaefer 《Operations Research Letters》2006,34(3):307-315
We consider a general adversarial stochastic optimization model. Our model involves the design of a system that an adversary may subsequently attempt to destroy or degrade. We introduce SPAR, which utilizes mixed-integer programming for the design decision and a Markov decision process (MDP) for the modeling of our adversarial phase. 相似文献
43.
Q. Cui 《Theoretical chemistry accounts》2006,116(1-3):51-59
Efficient vectorial processes such as the transduction of bioenergy and signals are characteristics that strikingly distinguish living systems from inanimate materials. Recent developments in biophysical and biochemical techniques have provided new information about the structure, dynamics and interaction of biomolecules involved in vectorial life processes at multiple length and temporal scales. This wealth of data makes it possible to carry out theoretical and computational studied of key mechanistic questions associated with complex life processes at an unprecedented level. Using two “vectorial biomolecular machines”, myosin and cytochrome c oxidase, as examples, we discuss the identification of interesting and biologically relevant questions that require thorough theoretical analysis. Technical challenges and recent progress related to these theoretical investigations are briefly summarized 相似文献
44.
Peter Friz Nicolas Victoir 《Annales de l'Institut Henri Poincaré (B) Probabilités et Statistiques》2007,43(6):775-785
We study large deviation principles for Gaussian processes lifted to the free nilpotent group of step N. We apply this to a large class of Gaussian processes lifted to geometric rough paths. A large deviation principle for enhanced (fractional) Brownian motion, in Hölder- or modulus topology, appears as special case. 相似文献
45.
We revealed the changes in the γ-luminescence spectra under the influence of a thermal radiation field on high-purity alkali-silicate
glasses (I) and those with addition of Fe3+ ions (II). We explain the obtained results within the framework of the L-model of edge absorption and electron-hole recombination
processes.
Samarkand State University, 15, Universitetskii Bul., Samarkand, 703004, Republic of Uzbekistan. Translated from Zhurnal Prikladnoi
Spektroskopii, Vol. 65, No. 3, pp. 453–455, May–June, 1998. 相似文献
46.
A. M. Chebotarev 《Mathematical Notes》1996,60(5):544-561
We prove that the Hudson-Parthasarathy equation corresponds, up to unitary equivalence, to the strong resolvent limit of Schrödinger Hamiltonians in Fock space and that the symmetric form of this equation corresponds to the weak limit of the Schrödinger Hamiltonians.Translated fromMatematicheskie Zametki, Vol. 60, No. 5, pp. 726–750, November, 1996. 相似文献
47.
P. A. V. Ferreira M. E. S. Machado 《Journal of Optimization Theory and Applications》1996,89(3):659-680
Projection and relaxation techniques are employed to decompose a multiobjective problem into a two-level structure. The basic manipulation consists in projecting the decision variables onto the space of the implicit tradeoffs, allowing the definition of a relaxed multiobjective master problem directly in the objective space. An additional subproblem tests the feasibility of the solution encountered by the relaxed problem. Some properties of the relaxed problem (linearity, small number of variables, etc.) render its solution efficient by a number of methods. Representatives of two different classes of multiobjective methods [the Geoffrion, Dyer, Feinberg (GDF) method and the fuzzy method of Baptistella and Ollero] are implemented and applied within this context to a water resources allocation problem. The results attest the computational viability of the overall procedure and its usefulness for the solution of multiobjective problems.This work was partially sponsored by grants from CNPq and FAPESP, Brazil. The authors are indebted to the anonymous reviewers for their valuable comments. 相似文献
48.
Klaus Ziegler 《Journal of multivariate analysis》1997,62(2):233-272
Functional central limit theorems for triangular arrays of rowwise independent stochastic processes are established by a method replacing tail probabilities by expectations throughout. The main tool is a maximal inequality based on a preliminary version proved by P. Gaenssler and Th. Schlumprecht. Its essential refinement used here is achieved by an additional inequality due to M. Ledoux and M. Talagrand. The entropy condition emerging in our theorems was introduced by K. S. Alexander, whose functional central limit theorem for so-calledmeasure-like processeswill be also regained. Applications concern, in particular, so-calledrandom measure processeswhich include function-indexed empirical processes and partial-sum processes (with random or fixed locations). In this context, we obtain generalizations of results due to K. S. Alexander, M. A. Arcones, P. Gaenssler, and K. Ziegler. Further examples include nonparametric regression and intensity estimation for spatial Poisson processes. 相似文献
49.
We use the topological tool of Nielsen fixed-point theory to study the controllability of perturbed linear control processes whose control space can be reduced to a finite-dimensional one. These methods produce a lower bound on the number of controls that achieve a given target. We concentrate particularly on the case where the perturbation has sublinear growth, and we exhibit examples of multiple controls of various types that are detected by the Nielsen theory method.This research was partly supported by the Research Grant Teoria del Controllo dei Sistemi Dinamici, Ministero della Pubblica Istruzione, Roma, Italy. 相似文献
50.
Let (E, ¦·¦) be a uniformly convex Banach space with the modulus of uniform convexity of power type. Let be the convolution of the distribution of a random series inE with independent one-dimensional components and an arbitrary probability measure onE. Under some assumptions about the components and the smoothness of the norm we show that there exists a constant such that |{·<t}–{·+r<t}|r
q
, whereq depends on the properties of the norm. We specify it in the case ofL
spaces, >1. 相似文献