全文获取类型
收费全文 | 16938篇 |
免费 | 1670篇 |
国内免费 | 1751篇 |
专业分类
化学 | 3925篇 |
晶体学 | 214篇 |
力学 | 1962篇 |
综合类 | 353篇 |
数学 | 11098篇 |
物理学 | 2807篇 |
出版年
2024年 | 21篇 |
2023年 | 150篇 |
2022年 | 184篇 |
2021年 | 289篇 |
2020年 | 436篇 |
2019年 | 390篇 |
2018年 | 374篇 |
2017年 | 450篇 |
2016年 | 497篇 |
2015年 | 371篇 |
2014年 | 709篇 |
2013年 | 1257篇 |
2012年 | 873篇 |
2011年 | 1026篇 |
2010年 | 988篇 |
2009年 | 1111篇 |
2008年 | 1186篇 |
2007年 | 1255篇 |
2006年 | 1033篇 |
2005年 | 949篇 |
2004年 | 877篇 |
2003年 | 891篇 |
2002年 | 737篇 |
2001年 | 577篇 |
2000年 | 495篇 |
1999年 | 476篇 |
1998年 | 428篇 |
1997年 | 353篇 |
1996年 | 291篇 |
1995年 | 268篇 |
1994年 | 225篇 |
1993年 | 153篇 |
1992年 | 151篇 |
1991年 | 118篇 |
1990年 | 110篇 |
1989年 | 81篇 |
1988年 | 78篇 |
1987年 | 57篇 |
1986年 | 62篇 |
1985年 | 65篇 |
1984年 | 55篇 |
1983年 | 28篇 |
1982年 | 58篇 |
1981年 | 47篇 |
1980年 | 31篇 |
1979年 | 27篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1974年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
991.
表面活性剂溶液动态表面张力及吸附动力学研究 总被引:8,自引:0,他引:8
本文简介了动态表面张力的定义、测定方法及吸附动力学,对非离子、阴离子、阳离子及两性表面活性剂溶液动态表面张力的研究情况进行了总结,重点讨论了浓度、温度、添加剂及化学结构因素对动态表面张力的影响. 相似文献
992.
993.
994.
Ultrasonic processing on sodium aluminate solutions was proved to have effects on the gibbsite crystallization process from sodium aluminate solution. In order to investigate the mechanism of the ultrasonic intensification, the sonofluorescence spectrum was detected by fluorescence spectrometer in sodium alumiante Luminol solutions, and the spectrum under the conditions of various ultrasonic power and different composition of sodium aluminate solutions were studied. It is found that the sodium aluminate Luminol solution can irradiate fluorescence by ultrasonic processing above the given power; the intensity of sonofluorescence are relatively low in sodium aluminate solutions with high concentration and low αk(mol ratio of Na2O/Al2O3 in sodium aluminate solution). The relationship between the sonofluorenscence and ultrasonic intensification on gibbsite crystallization process from sodium aluminate solutions were also discussed. The conclusion that the ultrasonic effects are influenced by ultrasonic cavitation and intensity of sonofluorescence spectrum is deduced. 相似文献
995.
We investigate a coupled quintessence scenario, which can provide a natural solution to the cosmic coincidence problem. We assume that the mass of dark matter particles depends on a power law function of the scalar field associated to dark energy and meanwhile the scalar field evolves in a power law potential. Since the dynamics of this system is dominated by an attractor solution, the mass of dark matter particles is forced to change with time as to ensure that the ratio between the energy densities of dark matter and dark energy becomes a constant at late times, and one thus solves the cosmic coincidence problem naturally. We then apply a statefinder diagnostic to this coupled quintessence scenario. It is shown that the evolving trajectory of this scenario in the s-r diagram is quite different from those of other dark energy models. 相似文献
996.
CHEN Jiang HE Hong-Sheng YANG Kong-Qing 《理论物理通讯》2005,44(2):307-310
A generalized F-expansion method is introduced and applied to (3+1 )-dimensional Kadomstev-Petviashvili(KP) equation. As a result, some new Jacobi elliptic function solutions of the equation are found, from which the trigonometric function solutions and the solitary wave solutions can be obtained. The method can also be extended to other types of nonlinear evolution equations in mathematical physics. 相似文献
997.
FU Zun-Tao LIN Guang-Xing LIU Shi-Kuo LIU Shi-Da 《理论物理通讯》2005,44(2):235-242
The new rational form solutions to the elliptic equation are shown, and then these solutions to the elliptic equation are taken as a transformation and applied to solve nonlinear coupled wave equations. It is shown that more novel kinds of solutions are derived, such as periodic solutions of rational form, solitary wave solutions of rational form,and so on. 相似文献
998.
XIE Fu-Ding 《理论物理通讯》2005,44(2):293-296
Some soliton solutions and periodic solutions of hybrid lattice, discretized mKdV lattice, and modified Volterra lattice have been obtained by introducing a new method. This approach allows us to directly construct some explicit exact solutions for polynomial nonlinear differential-difference equations. 相似文献
999.
New exact solutions, expressed in terms of the Jacobi elliptic functions, to
the nonlinear Klein--Gordon equation are obtained by using a modified mapping
method. The solutions include the conditions for equation's parameters and
travelling wave transformation parameters. Some figures for a specific kind
of solution are also presented. 相似文献
1000.