全文获取类型
收费全文 | 8884篇 |
免费 | 517篇 |
国内免费 | 99篇 |
专业分类
化学 | 5727篇 |
晶体学 | 103篇 |
力学 | 331篇 |
综合类 | 1篇 |
数学 | 1644篇 |
物理学 | 1694篇 |
出版年
2023年 | 68篇 |
2022年 | 139篇 |
2021年 | 188篇 |
2020年 | 166篇 |
2019年 | 265篇 |
2018年 | 277篇 |
2017年 | 211篇 |
2016年 | 401篇 |
2015年 | 297篇 |
2014年 | 406篇 |
2013年 | 815篇 |
2012年 | 649篇 |
2011年 | 636篇 |
2010年 | 447篇 |
2009年 | 386篇 |
2008年 | 446篇 |
2007年 | 471篇 |
2006年 | 416篇 |
2005年 | 378篇 |
2004年 | 332篇 |
2003年 | 266篇 |
2002年 | 294篇 |
2001年 | 110篇 |
2000年 | 149篇 |
1999年 | 92篇 |
1998年 | 62篇 |
1997年 | 74篇 |
1996年 | 76篇 |
1995年 | 68篇 |
1994年 | 60篇 |
1993年 | 54篇 |
1992年 | 52篇 |
1991年 | 39篇 |
1990年 | 32篇 |
1989年 | 44篇 |
1988年 | 36篇 |
1987年 | 31篇 |
1986年 | 23篇 |
1985年 | 47篇 |
1984年 | 43篇 |
1983年 | 31篇 |
1982年 | 38篇 |
1981年 | 37篇 |
1980年 | 28篇 |
1979年 | 28篇 |
1978年 | 30篇 |
1976年 | 25篇 |
1975年 | 28篇 |
1974年 | 18篇 |
1973年 | 20篇 |
排序方式: 共有9500条查询结果,搜索用时 15 毫秒
931.
Raca Todosijević Anis Mjirda Marko Mladenović Saïd Hanafi Bernard Gendron 《Optimization Letters》2017,11(6):1047-1056
In this paper, we present two general variable neighborhood search (GVNS) based variants for solving the traveling salesman problem with draft limits (TSPDL), a recent extension of the traveling salesman problem. TSPDL arises in the context of maritime transportation. It consists of finding optimal Hamiltonian tour for a given ship which has to visit and deliver products to a set of ports while respecting the draft limit constraints. The proposed methods combine ideas in sequential variable neighborhood descent within GVNS. They are tested on a set of benchmarks from the literature as well as on a new one generated by us. Computational experiments show remarkable efficiency and effectiveness of our new approach. Moreover, new set of benchmarks instances is generated. 相似文献
932.
Piotr Jeleń Magdalena Szumera Magdalena Gawęda Elżbieta Długoń Maciej Sitarz 《Journal of Thermal Analysis and Calorimetry》2017,129(1):103-108
Heat capacity of single-crystal samples of five chalcogenides (LiInS2, LiInSe2, LiGaS2, LiGaSe2, and LiGaTe2) was measured with DSC in a temperature range from 180 to 460 K. The data for LiInS2 and LiInSe2 were compared with the literature data and shown to agree with the results of adiabatic calorimetry (Gmelin and Hönle in Thermochimica Acta 269: 575–590, 1995) better than with other DSC data (Kühn et al. in Cryst Res Technol 22: 265–269, 1987). Besides, the high-temperature fitting polynomial for C P(T) published about 30 years ago for LiInS2 is wrong. LiGaS2, LiGaSe2, and LiGaTe2 were measured for the first time. 相似文献
933.
934.
Sandra Ulrich Ngueveu Stéphane Caux Frédéric Messine Mouloud Guemri 《4OR: A Quarterly Journal of Operations Research》2017,15(4):407-430
In hybrid electric vehicles, the electrical powertrain system has multiple energy sources that it can gather power from to satisfy the propulsion power requested by the vehicle at each instant. This paper focusses on the minimization of the fuel consumption of such a vehicle, taking advantage of the different energy sources. Based on global optimization approaches, the proposed heuristics find solutions that best split the power requested between the multi-electrical sources available. A lower bounding procedure is introduced to validate the quality of the solutions. Computational results show a significant improvement over previous results from the literature in both the computing time and the quality of the solutions. 相似文献
935.
Our aim in this paper is to prove an analog of the classical Titchmarsh theorem on the image under the discrete Fourier–Jacobi transform of a set of functions satisfying a generalized Lipschitz condition in the space . 相似文献
936.
937.
Tom Alberts Jeremy Clark Saša Kocić 《Stochastic Processes and their Applications》2017,127(10):3291-3330
We study a directed polymer model defined on a hierarchical diamond lattice, where the lattice is constructed recursively through a recipe depending on a branching number and a segment number . When it is known that the model exhibits strong disorder for all positive values of the inverse temperature , and thus weak disorder reigns only for (infinite temperature). Our focus is on the so-called intermediate disorder regime in which the inverse temperature vanishes at an appropriate rate as the size of the system grows. Our analysis requires separate treatment for the cases and . In the case we prove that when the inverse temperature is taken to be of the form for , the normalized partition function of the system converges weakly as to a distribution and does so universally with respect to the initial weight distribution. We prove the convergence using renormalization group type ideas rather than the standard Wiener chaos analysis. In the case we find a critical point in the behavior of the model when the inverse temperature is scaled as ; for an explicitly computable critical value the variance of the normalized partition function converges to zero with large when and grows without bound when . Finally, we prove a central limit theorem for the normalized partition function when . 相似文献
938.
Maria Chudnovsky Louis Esperet Laetitia Lemoine Peter Maceli Frédéric Maffray Irena Penev 《Journal of Graph Theory》2017,84(3):221-232
We prove that a graph G contains no induced ‐vertex path and no induced complement of a ‐vertex path if and only if G is obtained from 5‐cycles and split graphs by repeatedly applying the following operations: substitution, split unification, and split unification in the complement, where split unification is a new class‐preserving operation introduced here. 相似文献
939.
Well‐posedness and regularity results for a 2m‐th order parabolic equation in symmetric conical domains of ℝN+1
下载免费PDF全文
![点击此处可从《Mathematical Methods in the Applied Sciences》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Saïda Cherfaoui Amor Kessab Arezki Kheloufi 《Mathematical Methods in the Applied Sciences》2017,40(16):6035-6047
In this paper, we use the domain decomposition method to prove well‐posedness and smoothness results in anisotropic weighted Sobolev spaces for a multidimensional high‐order parabolic equation set in conical time‐dependent domains of . Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
940.
The application of the polytropic approximation connecting the quantities of corresponding state, to experimental analysis, is clarified. A method of polytropic determination of the exponent χ (variable but non-fluctuating) in each point of the flow is given. This approximation makes it possible the generation of representative signals of fluctuating quantities, like pressure or density. For heated gases, the problem of measurement of the equations terms written with Favre averaging is thus almost solved. Then, measurement of χ allows the determination by the experiment of crucial terms like turbulent fluxes of mass and momentum, and presso correlation. To cite this article: C. Rey, S. Benjeddou, C. R. Mecanique 332 (2004). 相似文献