全文获取类型
收费全文 | 65729篇 |
免费 | 7497篇 |
国内免费 | 4941篇 |
专业分类
化学 | 14478篇 |
晶体学 | 288篇 |
力学 | 7752篇 |
综合类 | 1309篇 |
数学 | 32516篇 |
物理学 | 21824篇 |
出版年
2024年 | 106篇 |
2023年 | 545篇 |
2022年 | 1226篇 |
2021年 | 1426篇 |
2020年 | 1612篇 |
2019年 | 1603篇 |
2018年 | 1519篇 |
2017年 | 2046篇 |
2016年 | 2317篇 |
2015年 | 1725篇 |
2014年 | 2996篇 |
2013年 | 4783篇 |
2012年 | 3264篇 |
2011年 | 3853篇 |
2010年 | 3455篇 |
2009年 | 4236篇 |
2008年 | 4243篇 |
2007年 | 4322篇 |
2006年 | 3782篇 |
2005年 | 3290篇 |
2004年 | 2936篇 |
2003年 | 2684篇 |
2002年 | 2614篇 |
2001年 | 2191篇 |
2000年 | 1946篇 |
1999年 | 1828篇 |
1998年 | 1643篇 |
1997年 | 1302篇 |
1996年 | 1162篇 |
1995年 | 1007篇 |
1994年 | 848篇 |
1993年 | 720篇 |
1992年 | 657篇 |
1991年 | 513篇 |
1990年 | 430篇 |
1989年 | 356篇 |
1988年 | 330篇 |
1987年 | 320篇 |
1986年 | 268篇 |
1985年 | 324篇 |
1984年 | 307篇 |
1983年 | 177篇 |
1982年 | 265篇 |
1981年 | 197篇 |
1980年 | 150篇 |
1979年 | 182篇 |
1978年 | 116篇 |
1977年 | 90篇 |
1976年 | 59篇 |
1973年 | 54篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
浅析二阶齐次线性变系数微分方程的一个可积类型 总被引:1,自引:0,他引:1
姬志飞 《应用数学与计算数学学报》2006,20(1):125-128
本文讨论了二阶齐次线性变系数微分方程的特殊形式,给出了这种微分方程的一个可积类型. 相似文献
82.
83.
84.
Most of the novel highly potent drugs, developed on the basis of modern molecular medicine, taking into account cell surface recognition techniques, show poor water solubility. A chemical modification of the drug substance enhancing the solubility often decreases the pharmacological activity. Thus, as an alternative an increase of the solubility can be obtained by the reduction of the size of the drug particles. Unfortunately, it is often difficult to obtain micro or nanosized drug particles by classical or more advanced crystallization using supercritical gases or by milling techniques. In addition, nanosized particles are often not physically stable and need to be stabilized in an appropriate matrix. Thus, it may be of interest to manufacture directly nanosized drug particles stabilized in an inert hydrophilic matrix, i.e. nanostructured and nanocomposite systems. Solid solutions and solid dispersions represent nanostructured and nanocomposite systems. In this context, the use of the vacuum-fluidized-bed technique for the spray-drying of a low water soluble drug cosolubilized with a hydrophilic excipient in a polar organic solvent is discussed. In order to avoid the use of organic solvents, a special spray-freeze-drying technique working at atmospheric pressure is presented. This process is very suitable for temperature and otherwise sensitive drugs such as pharmaproteins. 相似文献
85.
A. Mielke 《Journal of statistical physics》1991,62(3-4):509-528
The magnetic properties of the one-dimensional Hubbard model with a hardcore interaction on a ring (periodic boundary conditions) are investigated. At finite temperatures it is shown to behave up to exponentially small corrections as a pure paramagnet. An explicit expression for the ground-state degeneracies is derived. The eigenstates of this model are used to perform a perlurbational treatment for large but finite interactions. In first order inU
1 an effective Hamiltonian for the one-dimensional Hubbard model is derived. It is the Hamiltonian of the one-dimensional Hcisenberg model with antiferromagnetic couplings between nearest neighbor spins. An asymptotic expansion for the ground-state energy is given. The results are valid for arbitrary densities of electrons. 相似文献
86.
P. Le Bars 《Journal of Combinatorial Theory, Series A》2006,113(8):1771-1782
The aggregate error locator is defined and a computation method is given. The aggregate error locator is then used in a type of Forney algorithm to compute the error values in the received words of a Ca,b algebraic geometry code. 相似文献
87.
Lubomír Kubáček 《Applications of Mathematics》2006,51(6):565-582
Some remarks to problems of point and interval estimation, testing and problems of outliers are presented in the case of multivariate
regression model.
This work was supported by the Council of Czech Government J14/98:153100011. 相似文献
88.
89.
On Quantum Team Games 总被引:2,自引:0,他引:2
E. Ahmed M. F. Elettreby A. S. Hegazi 《International Journal of Theoretical Physics》2006,45(5):880-886
Recently Liu and Simaan (2004) convex static multi-team classical games have been introduced. Here they are generalized to both nonconvex, dynamic and quantum games. Puu's incomplete information dynamical systems are modified and applied to Cournot team game. The replicator dynamics of the quantum prisoner's dilemma game is also studied. 相似文献
90.
给出2005年全国部分高校研究生数学建模竞赛D题的研究背景,对参赛论文作了简要评注,并提供了一种参考解答. 相似文献