全文获取类型
收费全文 | 1851篇 |
免费 | 132篇 |
国内免费 | 56篇 |
专业分类
化学 | 1301篇 |
晶体学 | 11篇 |
力学 | 72篇 |
综合类 | 2篇 |
数学 | 302篇 |
物理学 | 351篇 |
出版年
2023年 | 16篇 |
2022年 | 43篇 |
2021年 | 40篇 |
2020年 | 49篇 |
2019年 | 48篇 |
2018年 | 35篇 |
2017年 | 29篇 |
2016年 | 86篇 |
2015年 | 63篇 |
2014年 | 83篇 |
2013年 | 119篇 |
2012年 | 126篇 |
2011年 | 151篇 |
2010年 | 83篇 |
2009年 | 107篇 |
2008年 | 116篇 |
2007年 | 104篇 |
2006年 | 84篇 |
2005年 | 80篇 |
2004年 | 76篇 |
2003年 | 71篇 |
2002年 | 62篇 |
2001年 | 17篇 |
2000年 | 34篇 |
1999年 | 16篇 |
1998年 | 11篇 |
1997年 | 17篇 |
1996年 | 19篇 |
1995年 | 21篇 |
1994年 | 19篇 |
1993年 | 13篇 |
1992年 | 11篇 |
1991年 | 15篇 |
1990年 | 14篇 |
1989年 | 4篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 4篇 |
1984年 | 21篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1980年 | 11篇 |
1979年 | 6篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 13篇 |
1974年 | 10篇 |
1973年 | 6篇 |
1972年 | 5篇 |
1970年 | 3篇 |
排序方式: 共有2039条查询结果,搜索用时 15 毫秒
131.
This study is motivated by the paper of Skouri et al. [Skouri, Konstantaras, Papachristos, Ganas, European Journal of Operational Research 192 (1) (2009) 79–92]. We extend their inventory model from ramp type demand rate and Weibull deterioration rate to arbitrary demand rate and arbitrary deterioration rate in the consideration of partial backorder. We demonstrate that the optimal solution is actually independent of demand. That is, for a finite time horizon, any attempt at tackling targeted inventory models under ramp type or any other types of the demand becomes redundant. Our analytical approach dramatically simplifies the solution procedure. 相似文献
132.
Leopoldo Eduardo Cárdenas-Barrón Hui-Ming Wee Mauricio F. Blos 《Mathematical and Computer Modelling》2011,53(5-6):991-997
In the past, economic order quantity (EOQ) and economic production quantity (EPQ) were treated independently from the viewpoints of the buyer or the vendor. In most cases, the optimal solution for one player was non-optimal to the other player. In today’s competitive markets, close cooperation between the vendor and the buyer is necessary to reduce the joint inventory cost and the response time of the vendor–buyer system. The successful experiences of National Semiconductor, Wal-Mart, and Procter and Gamble have demonstrated that integrating the supply chain has significantly influenced the company’s performance and market share (Simchi-Levi et al. (2000) [1]). Recently, Yang et al. (2007) [2] presented an inventory model to determine the economic lot size for both the vendor and buyer, and the number of deliveries in an integrated two stage supply chain. In this paper, we present an alternative approach to determine the global optimal inventory policy for the vendor–buyer integrated system using arithmetic–geometric inequality. 相似文献
133.
Wing Hung Wong 《Numerische Mathematik》1984,43(1):141-152
Summary The variational formulation of multivariate spline functions is generalized to include cases where the function has to satisfy inequality constraints such as positivity and convexity. Condition for existence and uniqueness of a solution is given. Approximation to the solution can be obtained by solving the variational problem in a finite dimensional subspace. Conditions for convergence and error estimates of the approximations are presented, both for interpolation problems and smoothing problems. The general theory is illustrated by specific examples including the volume-matching problem and the one-sided thin plate spline.This research is partially supported by the U.S. Army Contract No. DAAG 29-77-G-0207, and by NSF Grant No. MCS-8101836Part of this paper is based on Chapters 2 and 3 of the author's Ph. D. thesis. The author would like to express his sincere thanks to Professor Grance Wahba and to two referees for many helpful comments 相似文献
134.
Bis ( η1, η2-allyl) palladium phosphine complexes react with carbon dioxide and sulphur dioxide by insertion into the palladium-carbon σ-bond to give η3-allylpalladium-carboxylate and -S-sulphinate complexes. 相似文献
135.
We prove that the restriction of any nontrivial representation of the Ree groups 2 F 4(q), q = 22n+1 ≥ 8 in odd characteristic to any proper subgroup is reducible. We also determine all triples (K, V, H) such that ${K \in \{^2F_4(2), ^2F_4(2)'\} }We prove that the restriction of any nontrivial representation of the Ree groups 2
F
4(q), q = 22n+1 ≥ 8 in odd characteristic to any proper subgroup is reducible. We also determine all triples (K, V, H) such that K ? {2F4(2), 2F4(2)¢}{K \in \{^2F_4(2), ^2F_4(2)'\} } , H is a proper subgroup of K, and V is a representation of K in odd characteristic restricting absolutely irreducibly to H. 相似文献
136.
本文给出了一类非时齐的Markov链的强逼近.作为应用,建立了临床试验中Markov链自适应设计的强相合性,重对数律和弱收敛. 相似文献
137.
W Y Hung S Kucherenko N J Samsatli N Shah 《The Journal of the Operational Research Society》2004,55(8):801-813
In this paper, we present a new modelling approach for realistic supply chain simulation. The model provides an experimental environment for informed comparison between different supply chain policies. A basic simulation model for a generic node, from which a supply chain network can be built, has been developed using an object-oriented approach. This generic model allows the incorporation of the information and physical systems and decision-making policies used by each node. The object-oriented approach gives the flexibility in specifying the supply chain configuration and operation decisions, and policies. Stochastic simulations are achieved by applying Latin Supercube Sampling to the uncertain variables in descending order of importance, which reduces the number of simulations required. We also present a case study to show that the model is applicable to a real-life situation for dynamic stochastic studies. 相似文献
138.
We consider the first initial boundary-value problem for strongly parabolic systems in an infinite cylinder with nonsmooth boundary. We establish conditions for the existence of generalized solutions, an estimate for this solutions, and an estimate for the derivative of the solution. 相似文献
139.
In this paper we consider strong bilevel vector equilibrium problems and introduce the concepts of Levitin–Polyak well-posedness and Levitin–Polyak well-posedness in the generalized sense for such problems. The notions of upper/lower semicontinuity involving variable cones for vector-valued mappings and their properties are proposed and studied. Using these generalized semicontinuity notions, we investigate sufficient and/or necessary conditions of the Levitin–Polyak well-posedness for the reference problems. Some metric characterizations of these Levitin–Polyak well-posedness concepts in the behavior of approximate solution sets are also discussed. As an application, we consider the special case of traffic network problems with equilibrium constraints. 相似文献
140.
Pham Hung Quy 《Journal of Pure and Applied Algebra》2018,222(5):1126-1138
Let be an equidimensional excellent local ring of characteristic . The aim of this paper is to show that does not depend on the choice of parameter ideal provided R is an F-injective local ring that is F-rational on the punctured spectrum. 相似文献