首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5572篇
  免费   599篇
  国内免费   573篇
化学   1379篇
晶体学   8篇
力学   432篇
综合类   182篇
数学   3099篇
物理学   1644篇
  2024年   12篇
  2023年   55篇
  2022年   112篇
  2021年   159篇
  2020年   130篇
  2019年   150篇
  2018年   130篇
  2017年   191篇
  2016年   247篇
  2015年   189篇
  2014年   315篇
  2013年   387篇
  2012年   344篇
  2011年   320篇
  2010年   254篇
  2009年   375篇
  2008年   389篇
  2007年   364篇
  2006年   362篇
  2005年   306篇
  2004年   240篇
  2003年   226篇
  2002年   210篇
  2001年   172篇
  2000年   182篇
  1999年   134篇
  1998年   131篇
  1997年   120篇
  1996年   92篇
  1995年   57篇
  1994年   79篇
  1993年   37篇
  1992年   32篇
  1991年   30篇
  1990年   24篇
  1989年   27篇
  1988年   21篇
  1987年   12篇
  1986年   13篇
  1985年   26篇
  1984年   15篇
  1983年   8篇
  1982年   12篇
  1981年   15篇
  1980年   8篇
  1979年   8篇
  1978年   3篇
  1977年   5篇
  1976年   7篇
  1975年   3篇
排序方式: 共有6744条查询结果,搜索用时 15 毫秒
161.
《Optimization》2012,61(9):1075-1086
In this article, we establish some relationships between a solution of generalized vector variational-like inequalities and an efficient solution or a weakly efficient solution to the nonsmooth vector optimization problem under the assumptions of pseudoinvexity or invariant pseudomonotonicity. Our results extend and improve the corresponding results in the literature.  相似文献   
162.
《Optimization》2012,61(3):435-448
We give a definition of gamma-convergence (epi-convergence) for the case of vector valued sequences of functions and prove some related properties analogous to the scalar case. We obtain one of the main variational theorems about convergence of ?-minimizers. In the convex case, we consider also variable domains and obtain stability of efficient points and minimal values.  相似文献   
163.
We formulate a sufficient condition for the existence of a consistent price system (CPS), which is weaker than the conditional full support condition (CFS). We use the new condition to show the existence of CPSs for certain processes that fail to have the CFS property. In particular this condition gives sufficient conditions, under which a continuous function of a process with CFS admits a CPS, while the CFS property might be lost.  相似文献   
164.
In the present paper, we give an answer to a question which is closely related to doubly warped product of Finsler metrics: ‘‘For each n, is there an n-dimensional Finsler manifold (M,F), admitting a non-constant smooth function f on M such that fxigijyk=0?”. We relate the preceding mentioned condition to different concepts appeared and studied in Finsler geometry. We introduce and investigate the notion of a semi concurrent vector field on a Finsler manifold. We show that some special Finsler manifolds admitting such vector fields turn out to be Riemannian. We prove that Tachibana's characterization of Finsler manifolds admitting a concurrent vector field leads to Riemannian metrics. Various examples for conic Finsler spaces that admit semi-concurrent vector field are presented.  相似文献   
165.
Fang Lu 《Applicable analysis》2013,92(8):1567-1586
In the context of Euclidean spaces, we present an extension of the Newton-like method for solving vector optimization problems, with respect to the partial orders induced by a pointed, closed and convex cone with a nonempty interior. We study both exact and inexact versions of the Newton-like method. Under reasonable hypotheses, we prove stationarity of accumulation points of the sequences produced by Newton-like methods. Moreover, assuming strict cone-convexity of the objective map to the vector optimization problem, we establish convergence of the sequences to an efficient point whenever the initial point is in a compact level set.  相似文献   
166.
We study the well‐posedness of the fractional differential equations with infinite delay on Lebesgue–Bochner spaces and Besov spaces , where A and B are closed linear operators on a Banach space X satisfying ,  and . Under suitable assumptions on the kernels a and b, we completely characterize the well‐posedness of in the above vector‐valued function spaces on by using known operator‐valued Fourier multiplier theorems. We also give concrete examples where our abstract results may be applied.  相似文献   
167.
李科科  彭再云  赵勇  曾静 《数学学报》2019,62(4):653-662
本文借助集合极限的性质和弱f-性假设证明了含参广义集值强向量平衡问题解集映射的下半连续性,其方法不同于最近文献(Zhao,2016和Meng,2018).此外,建立了含参广义集值强向量平衡问题解集连通性的充分条件,并举例验证了所得结果的正确性.本文得结果推广和改进了已有文献(Gong,2008,Xu,2009,Chen,2010,Xu,2013和Zhao,2013)中相应结果.  相似文献   
168.
The design and synthesis of two families of molecular-gear prototypes is reported, with the aim of assembling them into trains of gears on a surface and ultimately achieving controlled intermolecular gearing motion. These piano-stool ruthenium complexes incorporate a hydrotris(indazolyl)borate moiety as tripodal rotation axle and a pentaarylcyclopentadienyl ligand as star-shaped cogwheel, equipped with five teeth ranging from pseudo-1D aryl groups to large planar 2D paddles. A divergent synthetic approach was followed, starting from a pentakis(p-bromophenyl)cyclopentadienyl ruthenium(II) complex as key precursor or from its iodinated counterpart, obtained by copper-catalyzed aromatic Br/I exchange. Subsequent fivefold cross-coupling reactions with various partners allowed high structural diversity to be reached and yielded molecular-gear prototypes with aryl-, carbazole-, BODIPY- and porphyrin-derived teeth of increasing size and length.  相似文献   
169.
《Mendeleev Communications》2020,30(4):462-464
  1. Download : Download high-res image (138KB)
  2. Download : Download full-size image
  相似文献   
170.
In this paper, we present examples of codes all of whose weight classes support 1‐designs, with duals whose classes include two that support 2‐designs. We can find these examples in the triply even binary codes of length 48, which have been classified by Betsumiya and Munemasa.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号