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   259篇
  免费   3篇
化学   128篇
晶体学   1篇
力学   3篇
数学   42篇
物理学   88篇
  2023年   2篇
  2022年   2篇
  2021年   1篇
  2018年   5篇
  2017年   2篇
  2016年   8篇
  2015年   4篇
  2014年   3篇
  2013年   12篇
  2012年   11篇
  2011年   8篇
  2010年   14篇
  2009年   7篇
  2008年   21篇
  2007年   14篇
  2006年   18篇
  2005年   13篇
  2004年   12篇
  2003年   8篇
  2002年   5篇
  2001年   2篇
  2000年   1篇
  1998年   2篇
  1997年   2篇
  1996年   5篇
  1995年   8篇
  1994年   3篇
  1993年   4篇
  1992年   5篇
  1991年   2篇
  1990年   6篇
  1989年   5篇
  1988年   3篇
  1987年   6篇
  1985年   3篇
  1984年   3篇
  1983年   2篇
  1982年   5篇
  1981年   4篇
  1980年   1篇
  1979年   3篇
  1978年   2篇
  1976年   2篇
  1974年   3篇
  1966年   1篇
  1955年   3篇
  1954年   3篇
  1935年   2篇
  1903年   1篇
排序方式: 共有262条查询结果,搜索用时 15 毫秒
51.
52.
Synthesis of metal–organic framework (MOF) based on tetra-pyridyl porphyrin and palladium (II) salt resulted in the formation of palladium oxide nano-crystals. The palladium oxide nano-crystals were characterized by PXRD, TEM, HRTEM, ED, UV–Vis spectroscopy, DLS, SEM and AFM. A plausible mechanism for the in situ generation of nano-crystals has been proposed.  相似文献   
53.
This paper surveys the existing literature on homogeneous operators and their relationships with projective representations ofPS L(2, ℝ) and other Lie groups. It also includes a list of open problems in this area.  相似文献   
54.
In this work, we have considered Cardassian Universe in Ho?ava-Lifshitz gravity. Four types of Cardassian Universe models i.e., polytropic/power law, modified polytropic, exponential and modified exponential models have been considered for accelerating models. The natures of statefinder parameters, deceleration parameter, Om diagnostic and EoS parameters have been investigated for all types of Cardassian models in Ho?ava-Lifshitz gravity.  相似文献   
55.
Using the ladder operator technique, a construction of the supersymmetric Hamiltonian is proposed. We show that the accidental degeneracies associated with the Coulomb and isotropic oscillator problems may be attributed to the existence of a supersymmetry of the Hamiltonians.  相似文献   
56.
This paper presents a new two-phase (TP) approximate method for real-time scheduling in a flexible manufacturing system (FMS). This method combines a reduced enumeration schedule generation algorithm with a 0–1 optimization algorithm. In order to make the combined algorithm practicable, heuristic rules are introduced for the selection of jobs to be scheduled. The relative performance of the TP method vis-a-vis conventional heuristic dispatching rules such as SPT, LPT, FCFS, MWKR, and LWKR is investigated using combined process-interaction/discrete-event simulation models. An efficient experimental procedure is designed and implemented using these models, and the statistical analysis of the results is presented. For the particular case investigated, the conclusions are very encouraging. In terms of mean flow time, the TP method performs significantly better than any other tested heuristic dispatching rules. Also, the experimental results show that using global information significantly improves the FMS performance.  相似文献   
57.
A fault diagnosis model for multiprocessor computers is proposed. Under normal operating mode each processor executes its own data. When an error occurs, the system is switched to the diagnostic mode. Previous input data for each processor is shifted to a different unit, to obtain a set of comparison results. We show that analysis of the test data to diagnose or locate faulty processors is equivalent to a 2-satisfiability problem. Under the assumption that discrepancy in a comparison result occurs if and only if at least one of the processors (being compared) is faulty, we prove that all the faulty processors can be diagnosed in O(n2) time, where n denotes the number of processors in the system.  相似文献   
58.
We study two-person stochastic games on a Polish state and compact action spaces and with average payoff criterion under a certain ergodicity condition. For the zero-sum game we establish the existence of a value and stationary optimal strategies for both players. For the nonzero-sum case the existence of Nash equilibrium in stationary strategies is established under certain separability conditions. Accepted 9 January 1997  相似文献   
59.
TheSU(3) F breaking effects are considered to fit the set of anomalous Ward identities in QCD. The solutions are then analysed and compared with a recent work that also deals with such identities.  相似文献   
60.
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