全文获取类型
收费全文 | 21439篇 |
免费 | 2333篇 |
国内免费 | 2093篇 |
专业分类
化学 | 2287篇 |
晶体学 | 31篇 |
力学 | 2395篇 |
综合类 | 509篇 |
数学 | 14295篇 |
物理学 | 6348篇 |
出版年
2024年 | 26篇 |
2023年 | 172篇 |
2022年 | 347篇 |
2021年 | 377篇 |
2020年 | 459篇 |
2019年 | 465篇 |
2018年 | 479篇 |
2017年 | 599篇 |
2016年 | 681篇 |
2015年 | 559篇 |
2014年 | 1077篇 |
2013年 | 1433篇 |
2012年 | 1114篇 |
2011年 | 1351篇 |
2010年 | 1189篇 |
2009年 | 1485篇 |
2008年 | 1461篇 |
2007年 | 1523篇 |
2006年 | 1356篇 |
2005年 | 1296篇 |
2004年 | 1058篇 |
2003年 | 962篇 |
2002年 | 816篇 |
2001年 | 751篇 |
2000年 | 689篇 |
1999年 | 602篇 |
1998年 | 535篇 |
1997年 | 517篇 |
1996年 | 362篇 |
1995年 | 300篇 |
1994年 | 262篇 |
1993年 | 209篇 |
1992年 | 166篇 |
1991年 | 136篇 |
1990年 | 139篇 |
1989年 | 98篇 |
1988年 | 89篇 |
1987年 | 80篇 |
1986年 | 71篇 |
1985年 | 84篇 |
1984年 | 71篇 |
1983年 | 49篇 |
1982年 | 65篇 |
1981年 | 60篇 |
1980年 | 38篇 |
1979年 | 38篇 |
1978年 | 31篇 |
1977年 | 26篇 |
1976年 | 30篇 |
1973年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Wilson A. Cañas-Marín Julián D. Ortiz-Arango Uriel E. Guerrero-Aconcha Claudia P. Soto-Tavera 《Fluid Phase Equilibria》2007
The ability of Soave–Redlich–Kwong cubic equation of state (SRK EoS) to predict densities and thermodynamic derivative properties such as thermal expansivity, isothermal compressibility, calorific capacity, and Joule–Thompson coefficients, for two gas condensates over a wide range of pressures (up to 110 MPa) was studied. The predictions of the EoS were compared to Monte Carlo simulation data obtained by Lagache et al. [M.H. Lagache, P. Ungerer, A. Boutin, Fluid Phase Equilibr. 220 (2004) 221]. Two completely different alpha functions for the SRK EoS attractive term were used and their respective effects on the predictions of such properties were analyzed. Also, two different forms of the crossed terms of the attractive parameter, aij, and three expressions of the crossed terms of the repulsive parameter, bij, were combined in different ways, and predictions were carried out. Little sensitivity of the properties on the chosen alpha function, except for the calorific capacities, was found in the systems studied. The most commonly used combination rules to model phase behavior of reservoir fluids, i.e. geometric and arithmetic forms of aij and bij, respectively, predicted very deficient results for these fluids at extreme conditions, specially for density calculations. 相似文献
92.
Roderich Tumulka 《Foundations of Physics》2007,37(2):186-197
In a recent paper Conway and Kochen, Found. Phys. 36, 2006, claim to have established that theories of the Ghirardi-Rimini-Weber
(RW) type, i.e., of spontaneous wave function collapse, cannot be made relativistic. On the other hand, relativistic GRW-type
theories have already been presented, in my recent paper, J. Stat. Phys. 125, 2006, and by Dowker and Henson, J. Stat. Phys.
115, 2004. Here, I elucidate why these are not excluded by the arguments of Conway and Kochen.
相似文献
93.
一个推广的Hardy-Hilbert型不等式及其逆式 总被引:1,自引:0,他引:1
本文引入单参数λ及应用Beta函数,给一个Hardy-Hilbert型不等式以具有最佳常数因子的推广,作为应用,给出了它的逆向形式. 相似文献
94.
95.
Differentiation of functions w.r.t. finite atomless measures with compact support on the real line is introduced. The related harmonic calculus is similar to that of the classical Lebesgue case. As an application we obtain the Weyl exponent for the spectral asymptotics of the Laplacians w.r.t. linear Cantor-type measures with arbitrary weights. 相似文献
96.
97.
In this paper, the deconvolution of SIMS profiles analysed at very low primary energy (0.5 keV/O2+) is addressed. The depth resolution function (DRF) of the SIMS analysis in presence of roughness is established and a deconvolution procedure is implemented without or in presence of roughness on samples containing delta-doped layers of boron in silicon. It is shown that the deconvolution procedure can lead to a great improvement of the full width at half maximum (FWHM) of the measured peaks in the case where no roughness in detected in the crater bottom. In the case where it is present, the conditions required to use a deconvolution procedure are discussed, and the deconvolution is implemented using precise and restrictive assumptions. 相似文献
98.
Differential inequality method, bounding function method and topological degree are applied to obtain the existence criterions of at least one solution for the general fourth-order differential equations under nonlinear boundary conditions, and many existing results are complemented. 相似文献
99.
Hui Ping Zhang 《数学学报(英文版)》2006,22(3):945-950
In this paper, we first define a kind of pseudo–distance function and annulus domain on Riemann surfaces, then prove the Hadamard
Theorem and the Borel–Carathéodory Theorem on any Riemann surfaces.
Supported by NSFC 10501052 相似文献
100.
一类广义Bent型S-Box的构造 总被引:1,自引:0,他引:1
王章雄 《数学的实践与认识》2002,32(6):999-1002
S-box是密码理论与实践中十分重要的一种装置 ,它的密码性能由其分量函数所决定 .于是 ,选择适当的分量函数来构造 S-box就成了一个重要的研究课题 .在一定意义上 ,Bent函数是最优良的密码函数 .本文通过函数序列半群和置换群来构造其任何非零线性组合为 Bent函数与线性函数之和的函数组 ,从而可由 Bent函数构造出具有高度非线性度和其他良好性状的 S-box 相似文献