全文获取类型
收费全文 | 2458篇 |
免费 | 168篇 |
国内免费 | 155篇 |
专业分类
化学 | 362篇 |
晶体学 | 17篇 |
力学 | 74篇 |
综合类 | 7篇 |
数学 | 840篇 |
物理学 | 1481篇 |
出版年
2023年 | 10篇 |
2022年 | 18篇 |
2021年 | 35篇 |
2020年 | 19篇 |
2019年 | 36篇 |
2018年 | 25篇 |
2017年 | 33篇 |
2016年 | 29篇 |
2015年 | 31篇 |
2014年 | 43篇 |
2013年 | 57篇 |
2012年 | 58篇 |
2011年 | 149篇 |
2010年 | 155篇 |
2009年 | 331篇 |
2008年 | 309篇 |
2007年 | 247篇 |
2006年 | 236篇 |
2005年 | 142篇 |
2004年 | 78篇 |
2003年 | 102篇 |
2002年 | 109篇 |
2001年 | 77篇 |
2000年 | 79篇 |
1999年 | 82篇 |
1998年 | 58篇 |
1997年 | 13篇 |
1996年 | 26篇 |
1995年 | 22篇 |
1994年 | 18篇 |
1993年 | 15篇 |
1992年 | 21篇 |
1991年 | 12篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1985年 | 12篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 2篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 9篇 |
排序方式: 共有2781条查询结果,搜索用时 27 毫秒
51.
52.
Richard Combes Marie-Noëlle Levelut Bernard Trémillon 《Journal of Electroanalytical Chemistry》1978,91(1):125-131
Reactions between cerium trichloride and oxide ions were studied in NaCl+KCl (1/1) at 1000°K, by potentiometry with a calcia-stabilized zirconia membrane electrode. Titration curves clearly demonstrated the existence of soluble cerium oxychloride (CeO+) and precipitated cerium oxide (Ce2O3), with respective dissociation constants 10?11 and 10?30 (molality scale). The corresponding conditional solubility diagram {log S (CeIII)=f(pO2?)} is presented and discussed. 相似文献
53.
T. A. Isaev N. S. Mosyagin A. V. Titov A. B. Alekseyev R. J. Buenker 《International journal of quantum chemistry》2002,88(5):687-690
The correlation calculation of the electronic structure of PbH is carried out with the generalized relativistic effective core potential (GRECP) and multireference single‐ and double‐excitation configuration interaction (MRD‐CI) methods. The 22‐electron GRECP for Pb is used and the outer core 5s, 5p, and 5d pseudospinors are frozen using the level‐shift technique, so only five external electrons of PbH are correlated. A new configuration selection scheme with respect to the relativistic multireference states is employed in the framework of the MRD‐CI method. The [6, 4, 3, 2] correlation spin–orbit basis set is optimized in the coupled cluster calculations on the Pb atom using a recently proposed procedure, in which functions in the spin–orbital basis set are generated from calculations of different ionic states of the Pb atom and those functions are considered optimal that provide the stationary point for some energy functional. Spectroscopic constants for the two lowest‐lying electronic states of PbH (2Π1/2, 2Π3/2) are found to be in good agreement with the experimental data. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002 相似文献
54.
A series of di- and trisilanes of general structure Ph3SiSiMe2R and (Ph3Si)2SiR′R″ were synthesized, and the 29Si and 13C chemical shifts and one-bond siliconsilicon coupling constants (1JSiSi) were measured. The coupling constants of the disilanes were found to be primarily dependent upon the inductive effect of the alkyl group, R, as measured by the Taft o★ constant. In both series of compounds, increasing alkyl substitution at silicon led to a decrease in 1JSiSi. 相似文献
55.
It is shown that the probability law of a diffusion process conditioned on weakly corrupted observations is asymptotically Gaussian when properly scaled. The method of proof involves Fisher information matrices and a Cramér-Rao inequality. 相似文献
56.
57.
A novel BF3-promoted [3+2] annulation of azonaphthalenes and ynamides is described.This protocol provides a modular and efficient entry to functionalized amino benzo[e]indole derivatives smoothly. 相似文献
58.
dx(t)=g(x{t))dW(t) is proved using an approximating sequence of stochastic delay equationsGeneralizations of the approximation scheme are indicated for the Stratonovich case and when the Brownian motion W is replaced by a continuous semi-martingale. 相似文献
59.
The main purpose of this paper is to investigate the connection between the Painlev′e property and the integrability of polynomial dynamical systems. We show that if a polynomial dynamical system has P... 相似文献
60.
Existence of positive solutions of singular boundary value problems related to Emden-Fowler equation is proved. A general minimization theorem in Sobolev spaces is applied. 相似文献