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   1090篇
  免费   41篇
  国内免费   20篇
化学   573篇
力学   59篇
数学   339篇
物理学   180篇
  2023年   11篇
  2022年   23篇
  2021年   40篇
  2020年   49篇
  2019年   46篇
  2018年   49篇
  2017年   39篇
  2016年   57篇
  2015年   26篇
  2014年   48篇
  2013年   92篇
  2012年   64篇
  2011年   60篇
  2010年   46篇
  2009年   35篇
  2008年   56篇
  2007年   52篇
  2006年   28篇
  2005年   29篇
  2004年   29篇
  2003年   19篇
  2002年   18篇
  2001年   6篇
  2000年   7篇
  1999年   10篇
  1998年   8篇
  1997年   13篇
  1996年   10篇
  1995年   14篇
  1994年   10篇
  1993年   8篇
  1992年   6篇
  1991年   5篇
  1990年   7篇
  1989年   8篇
  1987年   5篇
  1985年   14篇
  1984年   11篇
  1983年   4篇
  1982年   9篇
  1981年   6篇
  1980年   7篇
  1979年   8篇
  1978年   8篇
  1977年   11篇
  1976年   7篇
  1975年   9篇
  1974年   5篇
  1973年   4篇
  1972年   4篇
排序方式: 共有1151条查询结果,搜索用时 15 毫秒
1.
In this paper, we establish some criteria for boundedness, stability properties, and separation of solutions of autonomous nonlinear nabla Riemann-Liouville scalar fractional difference equations. To derive these results, we prove the variation of constants formula for nabla Riemann-Liouville fractional difference equations.  相似文献   
2.
Anh  Pham Ky  Vinh  Nguyen The 《Numerical Algorithms》2019,81(3):983-1001
Numerical Algorithms - In this paper, we introduce a self-adaptive inertial gradient projection algorithm for solving monotone or strongly pseudomonotone variational inequalities in real Hilbert...  相似文献   
3.
Necessary and sufficient conditions for qualitative properties of infinite dimensional linear programing problems such as solvability, duality, and complementary slackness conditions are studied in this article. As illustrations for the results, we investigate the parametric version of Gale’s example.  相似文献   
4.
In this work,the entropy functions of ideal quantum gases in a three-dimensional harmonic trap are analytically calculated using temperature as an explicit variable.Afterward,the applicability of the analytical formulas is validated by comparison with the numerical calculation.The results illustrate that the obtained functions could be applied for the whole temperature regime with a maximum relative deviation of less than 7.5%in the vicinity of the critical temperature Tcin the case of Bose gases.Meanwhile,for Fermi gases,although the analytical formula fits well at very low-and high-temperature regimes,it cannot be applied at temperature in the range[0.3-0.5]T_F,where T_F is the Fermi temperature.In addition,the consistency between our formulas and classical ones at significantly high temperatures is also discussed.  相似文献   
5.
Journal of Radioanalytical and Nuclear Chemistry - To keep the accredited category for the gamma spectrometry test in our laboratory, the efficiency curves of a HPGe detector for soil sample in...  相似文献   
6.
A nanostructured Mn3O4/C electrode was prepared by a one‐step polyol‐assisted pyro‐synthesis without any post‐heat treatments. The as‐prepared Mn3O4/C revealed nanostructured morphology comprised of secondary aggregates formed from carbon‐coated primary particles of average diameters ranging between 20 and 40 nm, as evidenced from the electron microscopy studies. The N2 adsorption studies reveal a hierarchical porous feature in the nanostructured electrode. The nanostructured morphology appears to be related to the present rapid combustion strategy. The nanostructured porous Mn3O4/C electrode demonstrated impressive electrode properties with reversible capacities of 666 mAh g?1 at a current density of 33 mA g?1, good capacity retentions (1141 mAh g?1 with 100 % Coulombic efficiencies at the 100th cycle), and rate capabilities (307 and 202 mAh g?1 at 528 and 1056 mA g?1, respectively) when tested as an anode for lithium‐ion battery applications.  相似文献   
7.
Density functional calculations are performed to study the energetic, structural, and electronic properties of graphene and silicene functionalized with hydrogen. Our calculations predict that H atoms bind much more strongly to silicene than to graphene. The adsorbed H atoms tend to cooperatively stabilize each other leading to a two‐dimensional nucleation and growth mechanism. The different structural and electronic modifications induced by H in fully functionalized graphene and silicene (known as graphane and silicane) are also explained. Finally, the electronic properties of defective graphane with multiple hydrogen vacancies are investigated. Engineering the vacancies in graphane offers a way to modify the electronic properties of this material.  相似文献   
8.
Donovan’s conjecture states that there exist only finitely many Morita equivalence classes of p-blocks with a given defect. This conjecture was shown by Radha Kessar to be equivalent to two other conjectures, one of which is that the basic algebras of p-blocks with a given defect can all be defined over a single finite field. We shall show that this latter conjecture is equivalent to the seemingly stronger statement that all p-blocks with a given defect can be defined over a single finite field.  相似文献   
9.
In this paper, we consider a wave equation with integral nonlocal boundary conditions of memory type. First, we establish two local existence theorems by using Faedo–Galerkin method and standard arguments of density. Next, we give a su?cient condition to guarantee the global existence and exponential decay of weak solutions. Finally, we present numerical results.  相似文献   
10.
In this paper, two splitting extragradient-like algorithms for solving strongly pseudomonotone equilibrium problems given by a sum of two bifunctions are proposed. The convergence of the proposed methods is analyzed and the R-linear rate of convergence under suitable assumptions on bifunctions is established. Moreover, a noisy data case, when a part of the bifunction is contaminated by errors, is studied. Finally, some numerical experiments are given to demonstrate the efficiency of our algorithms.  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