全文获取类型
收费全文 | 1567篇 |
免费 | 130篇 |
国内免费 | 83篇 |
专业分类
化学 | 332篇 |
晶体学 | 4篇 |
力学 | 144篇 |
综合类 | 29篇 |
数学 | 920篇 |
物理学 | 351篇 |
出版年
2024年 | 5篇 |
2023年 | 28篇 |
2022年 | 30篇 |
2021年 | 29篇 |
2020年 | 51篇 |
2019年 | 51篇 |
2018年 | 42篇 |
2017年 | 50篇 |
2016年 | 51篇 |
2015年 | 54篇 |
2014年 | 91篇 |
2013年 | 119篇 |
2012年 | 74篇 |
2011年 | 117篇 |
2010年 | 101篇 |
2009年 | 118篇 |
2008年 | 93篇 |
2007年 | 78篇 |
2006年 | 71篇 |
2005年 | 66篇 |
2004年 | 57篇 |
2003年 | 46篇 |
2002年 | 27篇 |
2001年 | 40篇 |
2000年 | 35篇 |
1999年 | 27篇 |
1998年 | 32篇 |
1997年 | 18篇 |
1996年 | 18篇 |
1995年 | 19篇 |
1994年 | 20篇 |
1993年 | 15篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 10篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1969年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有1780条查询结果,搜索用时 15 毫秒
1.
Rong Yin Jihui Zhang Xudong Shang 《Mathematical Methods in the Applied Sciences》2020,43(15):8736-8752
This paper is dedicated to studying the following Schrödinger–Poisson system Under some different assumptions on functions V(x), K(x), a(x) and f(u), by using the variational approach, we establish the existence of positive ground state solutions. 相似文献
2.
Svitlana P. Rogovchenko 《Journal of Mathematical Analysis and Applications》2003,279(1):121-134
In this paper, we are concerned with a class of nonlinear second-order differential equations with a nonlinear damping term. Passage to more general class of equations allows us to remove a restrictive condition usually imposed on the nonlinearity, and, as a consequence, our results apply to wider classes of nonlinear differential equations. Two illustrative examples are considered. 相似文献
3.
Tobias P. Kunzler Christoph M. Sprecher Nicholas D. Spencer 《Applied Surface Science》2006,253(4):2148-2153
Gradient surfaces allow rapid, high-throughput investigations and systematic studies in many disparate fields, including biology, tribology and adhesion. We describe a novel method for the fabrication of material-independent morphology gradients, involving a two-step process of particle erosion followed by a chemical polishing procedure that preferentially removes features with a small radius of curvature as a function of time. Gradients are fabricated on aluminium surfaces, but they may be readily transferred to other materials via a replication technique, which allows for the production of identical roughness gradient samples with any chosen surface chemistry. The gradients have been characterized by means of scanning electron microscopy and optical profilometry. Standard roughness parameters (Ra, Rq, Rz, Sm and Sk) were calculated from optical profilometry data. The roughness has also been assessed over different wavelength windows by means of a fast Fourier transformation approach. 相似文献
4.
In this paper, the possibility of using the gradients of the temperature and of the internal parameters as additional state variables in Continuum Thermodynamics is considered. The expressions of the two principles are discussed and Clausius–Duhem inequality is derived under an appropriate statement of the internal entropy production. Several formulations are proposed and compared to existing results in the literature. To cite this article: P. Ireman, Q.S. Nguyen, C. R. Mecanique 332 (2004). 相似文献
5.
By using the averaging technique, we obtain new oscillation criteria for second order delay differential equation with nonlinear neutral term. These results generalize and improve some known results about neutral delay differential equation of second order. 相似文献
6.
A self-consistent system of gravitational field with a binary mixture of perfect fluid and dark energy given by a cosmological
constant has been considered in Bianchi Type-V universe. The perfect fluid is chosen to be obeying either the equation of
state p=γρ with γ ε |0,1| or a van der Waals equation of state. The role of A-term in the evolution of the Bianchi Type-V universe has been
studied. 相似文献
7.
8.
9.
Summary A simplex method for determining the constantsS andk
o from the equation lnk’=lnk
o−S ϕ (was developed and applied to the reversed phase separation of high molar mass polystyrenes using gradients of any curvature.
Experimental retention times described using the equation had a standard deviation of 1.1%. The inclusion of a quadratic term
in the equation was found to be unwarranted. BothS and lnk
o varied linearly with ln molar mass. The logarithm of peak width of an eluting polystyrene peak was found to be a linear function
of the mobile phase composition at elution. The slope was equal toS. 相似文献
10.
M. Nagy 《Colloid and polymer science》1985,263(3):245-265