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   487篇
  免费   20篇
  国内免费   2篇
化学   301篇
晶体学   8篇
力学   2篇
数学   84篇
物理学   114篇
  2023年   3篇
  2022年   20篇
  2021年   21篇
  2020年   11篇
  2019年   10篇
  2018年   10篇
  2017年   17篇
  2016年   25篇
  2015年   20篇
  2014年   17篇
  2013年   21篇
  2012年   30篇
  2011年   36篇
  2010年   16篇
  2009年   14篇
  2008年   24篇
  2007年   20篇
  2006年   18篇
  2005年   27篇
  2004年   16篇
  2003年   20篇
  2002年   16篇
  2001年   4篇
  2000年   6篇
  1999年   3篇
  1997年   2篇
  1996年   4篇
  1995年   6篇
  1994年   4篇
  1993年   5篇
  1992年   5篇
  1991年   5篇
  1990年   2篇
  1989年   3篇
  1987年   3篇
  1985年   4篇
  1984年   2篇
  1983年   3篇
  1981年   2篇
  1979年   2篇
  1978年   6篇
  1975年   4篇
  1974年   3篇
  1973年   6篇
  1972年   3篇
  1935年   1篇
  1934年   2篇
  1933年   1篇
  1932年   1篇
  1931年   1篇
排序方式: 共有509条查询结果,搜索用时 134 毫秒
71.
Aequationes mathematicae - Given a probability space $$ (\Omega , {\mathcal {A}}, P) $$ , a complete and separable metric space X with the $$ \sigma $$ -algebra $$ {\mathcal {B}} $$ of all its...  相似文献   
72.
Periodica Mathematica Hungarica - In this note we construct an algorithm generating any discrete distribution with an arbitrary coin (and, as a result, with arbitrary initial distribution). The...  相似文献   
73.
New experimental and theoretical results are presented for the NMR shielding of oxygen in the carbonyl group. The experimental values clearly demonstrate that the solvent effects are very significant. The new results for the chemical shifts are in better agreement than the previous literature data with the corresponding ab initio values calculated for isolated molecules.  相似文献   
74.
The Galerkin-Petrov method is applied to the determination of the ground state energy of the beryllium atom. The basis set of the coordinate subspace consists of correlated wavefunctions of the combined configuration-interaction-Hylleraas type. The basis set of the projective subspace is of the configuration-interaction type. The usefulness of a previously proposed way of characterization of pairs of subspaces has been further confirmed. Experience in constructing close pairs of subspaces gathered in the case of two-electron systems is used for the larger system. Two methods for constructing pairs of subspaces are used in the calculations.  相似文献   
75.
Sesqui- and sesterterpenes of ophiobolin and fusicoccin families are important synthetic targets because of complexity of structure and potentially useful physiological activities, including anti-tumor activity. A synthesis of versatile building blocks for these terpenoids is described. Cyclopenta[8]annulene rings system with properly dislocated substituents was constructed using as key steps ring closing metathesis reaction and Wagner - Meerwein rearrangement. Ring closing metathesis reaction leading to cyclopenta[8]annulene was studied in detail.  相似文献   
76.
The a.c. impedance of Pt∣NaCl∣Pt and C∣NaCl∣C cells was measured in the frequency range from 10?3 to 103 Hz. Two contributions to the interface impedance could be distinguished, hindered charge transfer and an adsorption/desorption or slow reaction contribution, the latter being the rate determining step in the frequency range studied. An approximately symmetric nonlinear dependence of both the capacitance and the conductance on overvoltage was found at the lowest frequencies, indicating that the crystal/electrode interface is in a state which can be characterized as close to equilibrium. It should be ensured by two electrochemical reactions of approximately equal rates. The concept of a temporarily reversible electrode is introduced. It is a result of the ability of ions to discharge at the interface and to produce a finite reservoir of adsorbed or absorbed reaction products. An external voltage increases or reduces this reservoir, and therefore only a transient electric current may be carried by a backward reaction.  相似文献   
77.
States with private correlations but little or no distillable entanglement were recently reported. Here, we consider the secure distribution of such states, i.e., the situation when an adversary gives two parties such states and they have to verify privacy. We present a protocol which enables the parties to extract from such untrusted states an arbitrarily long and secure key, even though the amount of distillable entanglement of the untrusted states can be arbitrarily small.  相似文献   
78.
The air stable asarone-derived Ru carbene 16, a robust olefin metathesis catalyst, can be easily separated after reaction by deposition on silica gel and reused up to nine times. This procedure provides products of excellent purity with low Ru content.  相似文献   
79.
We study quantum information transmission over multiparty quantum channel. In particular, we show an equivalence of different capacity notions and provide a multiletter characterization of a capacity region for a general quantum channel with k senders and m receivers. We point out natural generalizations to the case of two-way classical communication capacity.  相似文献   
80.
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