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   165篇
  免费   1篇
  国内免费   2篇
化学   88篇
力学   5篇
数学   48篇
物理学   27篇
  2020年   3篇
  2017年   4篇
  2015年   4篇
  2013年   10篇
  2012年   4篇
  2011年   15篇
  2010年   6篇
  2008年   8篇
  2007年   10篇
  2006年   9篇
  2005年   7篇
  2004年   4篇
  2003年   3篇
  2002年   11篇
  2001年   4篇
  2000年   2篇
  1998年   2篇
  1997年   3篇
  1996年   2篇
  1993年   2篇
  1990年   2篇
  1985年   1篇
  1982年   2篇
  1980年   1篇
  1979年   6篇
  1978年   3篇
  1977年   1篇
  1976年   2篇
  1975年   3篇
  1974年   2篇
  1973年   1篇
  1972年   2篇
  1971年   1篇
  1970年   1篇
  1968年   1篇
  1967年   1篇
  1937年   3篇
  1936年   1篇
  1933年   1篇
  1931年   1篇
  1930年   1篇
  1906年   1篇
  1905年   1篇
  1904年   1篇
  1903年   1篇
  1896年   1篇
  1891年   1篇
  1883年   1篇
  1880年   1篇
  1878年   1篇
排序方式: 共有168条查询结果,搜索用时 15 毫秒
91.
Approximate nucleolus-based revenue sharing in airline alliances   总被引:1,自引:0,他引:1  
Alliances allow the airlines to extend their networks and increase the number of destinations they can access. Different from the traditional single airline approach, in an alliance, partner airlines may sell tickets for the same itinerary. In addition, one itinerary may consist of several flight legs, each of which may be operated by a different airline. A major issue that needs to be addressed is how to share the revenue generated from selling a ticket for a product among the individual airlines in a fair way. The fair allocation of the revenue has a critical importance for the long-term stability of the alliance. We model the problem as a cooperative game and show that the core of the game is non-empty. We propose to use a revenue proration scheme based on the concept of the nucleolus. The numerical studies reveal that the revenue shares can effectively be computed even for large alliance networks.  相似文献   
92.
93.
A formalism is presented for the calculation of relativistic corrections to molecular electronic energies and properties. After a discussion of the Dirac and Breit equations and their first-order Foldy-Wouthuysen [Phys. Rev. 78, 29 (1950)] transformation, we construct a second-quantization electronic Hamiltonian, valid for all values of the fine-structure constant alpha. The resulting alpha-dependent Hamiltonian is then used to set up a perturbation theory in orders of alpha(2), using the general framework of time-independent response theory, in the same manner as for geometrical and magnetic perturbations. Explicit expressions are given to second order in alpha(2) for the Hartree-Fock model. However, since all relativistic considerations are contained in the alpha-dependent Hamiltonian operator rather than in the wave function, the same approach may be used for other wave-function models, following the general procedure of response theory. In particular, by constructing a variational Lagrangian using the alpha-dependent electronic Hamiltonian, relativistic corrections can be calculated for nonvariational methods as well.  相似文献   
94.
Quasi-linear functionals are shown to be uniformly continuous and decomposable into a difference of two quasi-integrals. A predual space for the quasi-linear functionals inducing the weak*-topology is given. General constructions of quasi-linear functionals by solid set-functions and q-functions are given.

  相似文献   

95.
96.
97.
The kinetics of the acid-catalyzed ring opening of naphthalene 1,2-oxide (5) in highly aqueous media to give naphthols has been measured by heat-flow microcalorimetry. The reaction enthalpy of this aromatization reaction was measured as DeltaH = -51.3 +/- 1.7 kcal mol(-)(1). The unexpectedly low reactivity of naphthalene oxide is suggested to be due to an unusually large thermodynamic stability. A crude estimate of the stabilization effect, approximately 1 kcal mol(-)(1)(not a significant stabilization), is obtained by using the measured reaction enthalpies of structurally related substrates as references. A larger value (2.7 kcal mol(-)(1)) was obtained by calculation using the B3LYP hybrid functional corrected with solvation energies derived from semiempirical AM1/SM2 calculations. The origin of this effect is discussed in terms of homoconjugative stabilization and homoaromaticity. There is a good linear correlation (with slope = 0.63) between the experimentally measured free energy of activation and the calculated enthalpy of carbocation formation in water.  相似文献   
98.
99.
We prepared new varied diblock copolymers by ring‐opening metathesis polymerization of functionalized norbornenes and cyclooctene in the presence of Schrock‐type initiators, either [Mo(CHCMe2Ph)(N‐2,6‐iPr2Ph)(OCCH3(CF3)2)2] or [Mo(CHCMe2Ph)(N‐2,6‐iPr2Ph)(OC(CH3)3)2]. The block copolymers were microphase separated and presented the individual phases of each polymer block constituent, that were amorphous/amorphous, amorphous/semicrystalline, or semicrystalline/liquid‐crystalline. One example of such a block copolymer is shown.

  相似文献   

100.
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