全文获取类型
收费全文 | 30265篇 |
免费 | 1026篇 |
国内免费 | 13篇 |
专业分类
化学 | 20826篇 |
晶体学 | 226篇 |
力学 | 562篇 |
数学 | 4115篇 |
物理学 | 5575篇 |
出版年
2023年 | 251篇 |
2022年 | 172篇 |
2021年 | 339篇 |
2020年 | 502篇 |
2019年 | 457篇 |
2018年 | 664篇 |
2017年 | 615篇 |
2016年 | 1180篇 |
2015年 | 949篇 |
2014年 | 947篇 |
2013年 | 1986篇 |
2012年 | 2196篇 |
2011年 | 2345篇 |
2010年 | 1335篇 |
2009年 | 1067篇 |
2008年 | 1963篇 |
2007年 | 1923篇 |
2006年 | 1681篇 |
2005年 | 1514篇 |
2004年 | 1226篇 |
2003年 | 953篇 |
2002年 | 838篇 |
2001年 | 644篇 |
2000年 | 546篇 |
1999年 | 404篇 |
1998年 | 289篇 |
1997年 | 208篇 |
1996年 | 331篇 |
1995年 | 216篇 |
1994年 | 213篇 |
1993年 | 260篇 |
1992年 | 231篇 |
1991年 | 150篇 |
1990年 | 138篇 |
1989年 | 119篇 |
1988年 | 122篇 |
1987年 | 118篇 |
1986年 | 114篇 |
1985年 | 176篇 |
1984年 | 141篇 |
1983年 | 118篇 |
1982年 | 104篇 |
1981年 | 97篇 |
1980年 | 75篇 |
1979年 | 93篇 |
1978年 | 80篇 |
1977年 | 73篇 |
1976年 | 76篇 |
1975年 | 71篇 |
1973年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
The Faddeev-Reshetikhin-Takhtajan method to construct matrix bialgebras from nonsingular solutions of the quantum Yang-Baxter equation is extended to the anyonic or ? n -graded case. The resulting anyonic quantum matrices are braided groups in which the braiding is given by a phase factor. 相似文献
162.
Using the time differential perturbed angular correlation technique, the hyperfine interactions as titanium sites in ZnTiF6·6H2O and its decomposition products were determined between room temperature (300 K) and 1273 K. The different steps in the decomposition pattern were identified and a simple model is given for it. 相似文献
163.
A Bianchi V model, in the presence of a fluid with shear and rotation, is investigated. Asymptotic solutions are worked out, showing that shear and rotation may give rise to a conflict with present day observations, a problem that can be solved with the help of an inflationary solution. 相似文献
164.
The111Cd quadrupole coupling in the spinel CdCr2Se4 is investigated by TDPAC after different sample treatments. The experiments are consistent with Se vacancies causing the non-cubic probe environments and with the assumption that the majority of the111In atoms are positioned at A-sites. 相似文献
165.
M. Šícha J. Glosík J. Pavlík Z. Němeček J. Šafránková M. Tichý 《Czechoslovak Journal of Physics》1983,33(11):1226-1229
Conclusion In the present report an attempt has been made to use the second derivative method for measurements of the electron distribution function in flowing afterglow plasma. It has been shown that using the cross-correlation technique, this method seems to be a useful tool for flowing afterglow plasma investigation. 相似文献
166.
167.
168.
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
169.
We present an alternative, purely semantical and relatively simple, proof of the Statman's result that both intuitionistic propositional logic and its implicational fragment are PSPACE-complete.This paper was supported by grant 401/01/0218 of the Grant Agency of the Czech Republic. %
Mathematics Subject Classification (2000): 相似文献
170.
We present here an improved version of the method introduced by the first author to derive
pointwise gradient estimates for the solutions of one-dimensional parabolic problems. After considering
a general qualinear equation in divergence form we apply the method to the case of a nonlinear
diffusion-convection equation. The conclusions are stated first for classical solutions and then for
generalized and mild solutions. In the case of unbounded initial datum we obtain several regularizing
effects for t > 0. Some unilateral pointwise gradient
estimates are also obtained. The case of
the Dirichlet problem is also considered. Finally, we collect, in the last section, several comments
showing the connections among these estimates and the study of the free boundaries
associated to the solutions of the diffusion-convection equation. 相似文献