全文获取类型
收费全文 | 104321篇 |
免费 | 17497篇 |
国内免费 | 12568篇 |
专业分类
化学 | 73707篇 |
晶体学 | 1205篇 |
力学 | 5996篇 |
综合类 | 751篇 |
数学 | 13253篇 |
物理学 | 39474篇 |
出版年
2024年 | 107篇 |
2023年 | 2113篇 |
2022年 | 2412篇 |
2021年 | 3420篇 |
2020年 | 4379篇 |
2019年 | 4116篇 |
2018年 | 3769篇 |
2017年 | 3449篇 |
2016年 | 5097篇 |
2015年 | 4953篇 |
2014年 | 6160篇 |
2013年 | 7998篇 |
2012年 | 9592篇 |
2011年 | 9939篇 |
2010年 | 7006篇 |
2009年 | 6687篇 |
2008年 | 7051篇 |
2007年 | 6282篇 |
2006年 | 5865篇 |
2005年 | 4866篇 |
2004年 | 3817篇 |
2003年 | 2976篇 |
2002年 | 2664篇 |
2001年 | 2275篇 |
2000年 | 1931篇 |
1999年 | 2044篇 |
1998年 | 1731篇 |
1997年 | 1544篇 |
1996年 | 1513篇 |
1995年 | 1366篇 |
1994年 | 1256篇 |
1993年 | 1001篇 |
1992年 | 900篇 |
1991年 | 789篇 |
1990年 | 653篇 |
1989年 | 503篇 |
1988年 | 376篇 |
1987年 | 338篇 |
1986年 | 332篇 |
1985年 | 268篇 |
1984年 | 190篇 |
1983年 | 155篇 |
1982年 | 127篇 |
1981年 | 80篇 |
1980年 | 60篇 |
1979年 | 25篇 |
1978年 | 23篇 |
1976年 | 23篇 |
1975年 | 23篇 |
1957年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
991.
We construct a nonauto Darboux transformation for the extended noncommutative Kadomtsev–Petviashvili (ncKP) hierarchy and consequently derive its quasi-Wronskian solution. We also obtain the quasi-Wronskian solution of the ncKP equation with self-consistent sources (ncKPESCS) as a by-product. Finally, we use the direct verification method to prove the quasi-Wronskian solution of the ncKPESCS. 相似文献
992.
In this paper, the parakähler Hom-Lie algebras or phase space of Hom-Lie algebras in terms of Hom-left-symmetric algebras are studied. A structure theory of parakähler Hom-Lie algebras in terms of matched pairs of Hom-Lie algebras is also presented. Besides, the bimodules of Hom-left-symmetric algebras are investigated. Furthermore, Hom-left-symmetric bialgebra which is precisely equivalent to parakähler Hom-Lie algebra is introduced. Especially, the coboundary Hom-left-symmetric bialgebra is considered. 相似文献
993.
Siberian Mathematical Journal - We give Gröbner–Shirshov bases for the Drinfeld–Kohno Lie algebra L n in [1] and the Kukin Lie algebra A P in [2], where P is a semigroup. By way of... 相似文献
994.
Xiao-Bing Li Zhi Lin Qi-Lin Wang Jia-Wei Chen 《Numerical Functional Analysis & Optimization》2017,38(11):1410-1425
This paper is concerned with Hölder continuity of the solution to a saddle point problem. Some new su?cient conditions for the uniqueness and Hölder continuity of the solution for a perturbed saddle point problem are established. Applications of the result on Hölder continuity of the solution for perturbed constrained optimization problems are presented under mild conditions. Examples are given to illustrate the obtained results. 相似文献
995.
Rui Shen Zhiqing Meng Chuangyin Dang Min Jiang 《Numerical Functional Analysis & Optimization》2017,38(11):1473-1489
In this paper, an algorithm of barrier objective penalty function for inequality constrained optimization is studied and a conception–the stability of barrier objective penalty function is presented. It is proved that an approximate optimal solution may be obtained by solving a barrier objective penalty function for inequality constrained optimization problem when the barrier objective penalty function is stable. Under some conditions, the stability of barrier objective penalty function is proved for convex programming. Specially, the logarithmic barrier function of convex programming is stable. Based on the barrier objective penalty function, an algorithm is developed for finding an approximate optimal solution to an inequality constrained optimization problem and its convergence is also proved under some conditions. Finally, numerical experiments show that the barrier objective penalty function algorithm has better convergence than the classical barrier function algorithm. 相似文献
996.
In this paper we give a uniform way of proving cartesian closedness for many new subcategories of continuous posets. We define C-P to be the category of continuous posets whose D–completions are isomorphic to objects from C, where C is a subcategory of the category CONT of domains. The main result is that if C is a cartesian closed full subcategory of ALG ⊥ or BC, then C-P is also a cartesian closed subcategory of the category CONTP of continuous posets and Scott continuous functions. In particular, we have the following cartesian closed categories : BC-P, LAT-P, aL-P, aBC-P, B-P, aLAT-P, ω -B-P, ω -aLAT-P, etc. 相似文献
997.
In this paper, we determine the universal central extension, derivation algebra and automorphism group of the twisted N = 1 Schrödinger–Neveu–Schwarz algebra. Furthermore, we generalize these results to the generalized twisted N = 1 Schrödinger–Neveu–Schwarz algebra in the final section. 相似文献
998.
999.
Xiao Shi Yongjun Li Ali Emrouznejad Jianhui Xie Liang Liang 《The Journal of the Operational Research Society》2017,68(9):1045-1055
This paper develops a novel two-stage cost efficiency model to estimate and decompose the potential gains from Mergers and Acquisitions (M&As). In this model, a hypothetical DMU is defined as a combination of two or more candidate DMUs. The hypothetical DMU would surpass the traditional Production Possibility Set (PPS). In order to solve the problem, a Merger Production Possibility Set (PPSM) is constructed. The model minimizes the total cost of the hypothetical DMU while maintaining its outputs at the current level, and estimates the overall merger efficiency by comparing its minimal total cost with its actual cost. Moreover, the overall merger efficiency could be decomposed into technical efficiency, harmony efficiency, and scale efficiency. We show that the model can be extended to a two-stage structure and these efficiencies can be decomposed to both sub-systems. To show the usefulness of the proposed approach, we applied it to a real dataset of top 20 most competitive Chinese City Commercial Banks (CCBs). We concluded that (1) there exist considerably potential gains for the proposed merged banks. (2) It is also shown that the main impact on potential merger gains are from technical and harmony efficiency. (3) As an interesting result we found that the scale effect works against the merger, indicating that it is not favorable for a full-scale merger. 相似文献
1000.
A weighted graph is a graph in which every edge is assigned a non-negative real number. In a weighted graph, the weight of a path is the sum of the weights of its edges, and the weighed degree of a vertex is the sum of the weights of the edges incident with it. In this paper we give three weighted degree conditions for the existence of heavy or Hamilton paths with one or two given end-vertices in 2-connected weighted graphs. 相似文献