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   10191篇
  免费   207篇
  国内免费   74篇
化学   404篇
晶体学   10篇
力学   66篇
综合类   6篇
数学   9436篇
物理学   550篇
  2023年   19篇
  2022年   18篇
  2021年   25篇
  2020年   54篇
  2019年   279篇
  2018年   284篇
  2017年   167篇
  2016年   135篇
  2015年   120篇
  2014年   247篇
  2013年   611篇
  2012年   273篇
  2011年   595篇
  2010年   496篇
  2009年   676篇
  2008年   788篇
  2007年   810篇
  2006年   607篇
  2005年   380篇
  2004年   353篇
  2003年   316篇
  2002年   246篇
  2001年   191篇
  2000年   194篇
  1999年   245篇
  1998年   227篇
  1997年   163篇
  1996年   242篇
  1995年   214篇
  1994年   202篇
  1993年   171篇
  1992年   120篇
  1991年   87篇
  1990年   87篇
  1989年   88篇
  1988年   59篇
  1987年   60篇
  1986年   65篇
  1985年   88篇
  1984年   61篇
  1983年   51篇
  1982年   63篇
  1981年   60篇
  1980年   54篇
  1979年   39篇
  1978年   44篇
  1977年   35篇
  1976年   38篇
  1975年   10篇
  1974年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
We study the existence, uniqueness and stability of solutions of general stochastic differential equations with constraints driven by semimartingales and processes with bounded p-variation. Applications to SDEs with constraints driven by fractional Brownian motion and standard Brownian motion are given.  相似文献   
32.
We study the decimation to a sublattice of half the sites of the one-dimensional Dyson–Ising ferromagnet with slowly decaying long-range pair potentials of the form 1|i?j|α, deep in the phase transition region (1<α2 and low temperature). We prove non-Gibbsianness of the decimated measures at low enough temperatures by exhibiting a point of essential discontinuity for the (finite-volume) conditional probabilities of decimated Gibbs measures. This result complements previous work proving conservation of Gibbsianness for fastly decaying potentials (α>2) and provides an example of a “standard” non-Gibbsian result in one dimension, in the vein of similar results in higher dimensions for short-range models. We also discuss how these measures could fit within a generalized (almost vs. weak) Gibbsian framework. Moreover we comment on the possibility of similar results for some other transformations.  相似文献   
33.
34.
35.
36.
Three ternary copper(II) complexes, [Cu(phen)(L-phe)Cl]·2H2O, [Cu(phen)(L-leu)Cl]·4½H2O, and [Cu(phen)(L-tyr)Cl]·3H2O, and four binary copper(II) complexes, [Cu(phen)Cl2], Cu(L-phe)2·½H2O, Cu(L-leu)2·½H2O, and Cu(L-tyr)2·H2O (where phen = 110-phenanthroline, L-phe = L-phenylalanine, L-tyr = L-tyrosine, L-leu = L-leucine and Cl- = chloride), were synthesized and characterized by elemental analysis, spectroscopic techniques (FTIR, UV–visible, fluorescence spectroscopy), magnetic susceptibility, molar conductivity, and lipophilicity measurement. X-ray diffraction determination of a single crystal of [Cu(phen)(L-tyr)Cl] showed two independent molecules in the asymmetric unit, each with the same distorted square pyramidal geometry about copper(II). p-Nitrosodimethylaniline assay revealed that the three ternary complexes were better inducers of reactive oxygen species over time than binary complexes, CuCl2, and free ligands. All the copper(II) complexes in this series inhibited the three proteolytic activities in the order Trypsin-like > Caspase-like > Chymotrypsin-like. In terms of anticancer properties, the copper(II)-phen complexes had GI50 values of less than 4 μM against MCF-7, HepG2, CNE1 and A549 cancer cell lines, more potent than cisplatin.  相似文献   
37.
A new condition for solvable groups   总被引:1,自引:0,他引:1  
A subgroup H of G is called complemented in G if there exists a subgroup K of G such that G=HK and HK=1. The aim of this paper is to prove the following: A finite group G is solvable if and only if its Sylow 3-, 5- and 7-subgroups are complemented in G.  相似文献   
38.
A finite group G is exceptional if it has a quotient Q whose minimal faithful permutation degree is greater than that of G. We say that Q is a distinguished quotient.The smallest examples of exceptional p-groups have order p5. For an odd prime p, we classify all pairs (G,Q) where G has order p5 and Q is a distinguished quotient. (The case p=2 has already been treated by Easdown and Praeger.) We establish the striking asymptotic result that as p increases, the proportion of groups of order p5 with at least one exceptional quotient tends to 1/2.  相似文献   
39.
《Mathematische Nachrichten》2017,290(14-15):2388-2400
In this paper, we study the high‐dimensional Hausdorff type operators and establish their boundedness on the power weighted Hardy spaces 201600257:mana201600257-math-0003" class="section_image" src="/cms/asset/77d0f003-0f41-4405-9e37-1327ea78d1aa/mana201600257-math-0003.png"> for 201600257:mana201600257-math-0004" class="section_image" src="/cms/asset/54f15b04-ff1b-450f-9d5a-3e6833cc1436/mana201600257-math-0004.png">. As a consequence, we obtain that the Hausdorff type operator 201600257:mana201600257-math-0005" class="section_image" src="/cms/asset/3bb39435-3fba-43a3-95b5-408efc7b3a53/mana201600257-math-0005.png"> is bounded on 201600257:mana201600257-math-0006" class="section_image" src="/cms/asset/53e4bc36-68fa-40ef-a815-a9e041957d47/mana201600257-math-0006.png"> if Φ is the Gauss function, or the Poisson function.  相似文献   
40.
《Mathematische Nachrichten》2017,290(17-18):2759-2774
Here we give a new approach to the Paley–Wiener theorem in a Mellin analysis setting which avoids the use of the Riemann surface of the logarithm and analytical branches and is based on new concepts of polar‐analytic function in the Mellin setting and Mellin–Bernstein spaces. A notion of Hardy spaces in the Mellin setting is also given along with applications to exponential sampling formulas of optical physics.  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