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   118篇
  免费   0篇
化学   67篇
数学   20篇
物理学   31篇
  2020年   1篇
  2018年   1篇
  2016年   1篇
  2014年   2篇
  2013年   5篇
  2012年   4篇
  2011年   5篇
  2010年   3篇
  2009年   1篇
  2008年   5篇
  2007年   2篇
  2006年   2篇
  2005年   3篇
  2004年   1篇
  2003年   3篇
  2002年   1篇
  2001年   3篇
  2000年   3篇
  1999年   3篇
  1996年   3篇
  1995年   2篇
  1994年   3篇
  1992年   5篇
  1991年   1篇
  1989年   2篇
  1987年   2篇
  1986年   1篇
  1983年   2篇
  1982年   1篇
  1981年   2篇
  1980年   5篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
  1976年   3篇
  1975年   4篇
  1974年   4篇
  1973年   6篇
  1972年   1篇
  1971年   2篇
  1970年   2篇
  1969年   1篇
  1968年   4篇
  1966年   4篇
  1965年   4篇
排序方式: 共有118条查询结果,搜索用时 0 毫秒
11.
12.
13.
We present time-resolved emission experiments of semiconductor quantum dots in silicon 3D inverse-woodpile photonic band gap crystals. A systematic study is made of crystals with a range of pore radii to tune the band gap relative to the emission frequency. The decay rates averaged over all dipole orientations are inhibited by a factor of 10 in the photonic band gap and enhanced up to 2× outside the gap, in agreement with theory. We discuss the effects of spatial inhomogeneity, nonradiative decay, and transition dipole orientations on the observed inhibition in the band gap.  相似文献   
14.
Unexpected events, such as accidents or track damages, can have a significant impact on the railway system so that trains need to be canceled and delayed. In case of a disruption it is important that dispatchers quickly present a good solution in order to minimize the nuisance for the passengers. In this paper, we focus on adjusting the timetable of a passenger railway operator in case of major disruptions. Both a partial and a complete blockade of a railway line are considered. Given a disrupted infrastructure situation and a forecast of the characteristics of the disruption, our goal is to determine a disposition timetable, specifying which trains will still be operated during the disruption and determining the timetable of these trains. Without explicitly taking the rolling stock rescheduling problem into account, we develop our models such that the probability that feasible solutions to this problem exist, is high. The main objective is to maximize the service level offered to the passengers. We present integer programming formulations and test our models using instances from Netherlands Railways.  相似文献   
15.
When tracks are out of service for maintenance during a certain period, trains cannot be operated on those tracks. This leads to a modified timetable, and results in infeasible rolling stock and crew schedules. Therefore, these schedules need to be repaired. The topic of this paper is the re-scheduling of crew.  相似文献   
16.
Numerical simulations are reported for the response of three-dimensional cross-linked F-actin networks when subjected to large deformations. In addition to the physiological parameters such as actin and cross-linker concentration, the model explicitly accounts for filament properties and network architecture. Complementary to two-dimensional studies, we find that the strain-stiffening characteristics depend on network architecture through the local topology around cross-links.  相似文献   
17.
After the publication of the work entitled "Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity", by Kozlowski et al., BMC Biochemistry 2011, 12:29, we found that the legends to Figures 2 to 5 contain serious mistakes that compromise the comprehension of the work. This correction article contains the correct text of the legends to Figures 2 to 5.  相似文献   
18.
The computation of the cheapest path between each pair of states of certain multistage systems can be formulated as a summation of matrix power-series over the algebraic structure (R, max, +). We analyse the convergence properties of such power-series.  相似文献   
19.
The synthesis of endo-3,6-epoxy-Δ4-tetrahydrophthalic anhydride from the endo-adduct of furan and maleic acid is described. Reduction of endo- and exo-3,6-epoxy-Δ4-tetrahydrophthalic anhydride with sodium borohydride gave the corresponding lactones, while catalytic hydrogenation over 10% Pd/C gave anhydride and/or hemi-acylals, depending on the solvent.  相似文献   
20.
The 1s-forms of TaSe2 and TaS2 with octahedral coordination of the metal are diamagnetic; 1s-TaS2 is a semiconductor at low temperature. The diamagnetism is explained by taking account of spin-orbit coupling which leads to a ground state with zero magnetic moment (g = 0). This spin-orbit coupling stabilizes the d1 configuration of the metal with respect to d2 + d0. Thus, it can be understood that 1sTaS2 is semiconducting, while isostructural VSe2 is metallic. Similarly, BaTaS2 and BaTaSe3 are semiconductors, but BaVS3 is metallic.  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