全文获取类型
收费全文 | 17205篇 |
免费 | 2705篇 |
国内免费 | 1741篇 |
专业分类
化学 | 12054篇 |
晶体学 | 171篇 |
力学 | 893篇 |
综合类 | 138篇 |
数学 | 2023篇 |
物理学 | 6372篇 |
出版年
2024年 | 24篇 |
2023年 | 347篇 |
2022年 | 506篇 |
2021年 | 567篇 |
2020年 | 733篇 |
2019年 | 668篇 |
2018年 | 563篇 |
2017年 | 546篇 |
2016年 | 825篇 |
2015年 | 811篇 |
2014年 | 962篇 |
2013年 | 1187篇 |
2012年 | 1581篇 |
2011年 | 1538篇 |
2010年 | 1040篇 |
2009年 | 950篇 |
2008年 | 1151篇 |
2007年 | 1002篇 |
2006年 | 929篇 |
2005年 | 761篇 |
2004年 | 556篇 |
2003年 | 454篇 |
2002年 | 401篇 |
2001年 | 349篇 |
2000年 | 364篇 |
1999年 | 357篇 |
1998年 | 327篇 |
1997年 | 271篇 |
1996年 | 290篇 |
1995年 | 252篇 |
1994年 | 199篇 |
1993年 | 172篇 |
1992年 | 155篇 |
1991年 | 136篇 |
1990年 | 106篇 |
1989年 | 77篇 |
1988年 | 75篇 |
1987年 | 67篇 |
1986年 | 54篇 |
1985年 | 56篇 |
1984年 | 35篇 |
1983年 | 34篇 |
1982年 | 24篇 |
1981年 | 20篇 |
1980年 | 16篇 |
1979年 | 9篇 |
1977年 | 10篇 |
1976年 | 16篇 |
1975年 | 9篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 928 毫秒
11.
We numerically solve the time-dependent Ginzburg–Landau equations for two-gap superconductors using the finite-element technique. The real-time simulation shows that at low magnetic field, the vortices in small-size samples tend to form clusters or other disorder structures. When the sample size is large, stripes appear in the pattern. These results are in good agreement with the previous experimental observations of the intriguing anomalous vortex pattern, providing a reliable theoretical basis for the future applications of multi-gap superconductors. 相似文献
12.
13.
14.
Yu Wang Xin-jing Zhao Rong-Jing Wei Gui-jie Liang Kang Wang Yuan-zhi Tan Ye Yang 《化学物理学报(中文版)》2021,34(5):591-597
The intermolecular interaction determines the photophysical properties of the organic aggregates, which are critical to the performance of organic photovoltaics. Here, excitonic coupling, an important intermolecular interaction in organic aggregates, between the π-stacking graphene quantum dots is studied by using transient absorption spectroscopy. We find that the spectral evolution of the ground state bleach arises from the dynamic variation of the excitonic coupling in the excited π-stacks. According to the spectral simulations, we demonstrate that the kinetics of the vibronic peak can be exploited as a probe to measure the dynamics of excitonic coupling in the excited π-stacks. 相似文献
15.
In this paper, we consider a viscoelastic wave equation of variable coefficients in the presence of past history with nonlinear damping and delay in the internal feedback and dynamic boundary conditions. Under suitable assumptions, we establish an explicit and general decay rate result without imposing restrictive assumption on the behavior of the relaxation function at infinity by Riemannian geometry method and Lyapunov functional method. 相似文献
16.
The γcmc values of CTAB-SDS decrease from 63.67 mN/m at 10‡C to 36.38 mN/m at 90‡C, slightly lower than those of either CTAB or SDS.
Correspondingly, the CMC of CTAB-SDS decreases almost by half. The increase of surface activity of CTAB-SDS can be attributed
to the relatively weak electrostatic interaction at high temperature, which is supported by the increase of solubility of
CTAB-SDS with rise in temperature. Catalytic effect on oxidation of toluene derivatives with potassium permanganate follows
the order CTAB-SDS > SDS > CTAB. This is not caused by the dissociative effect of CTAB-SDS with low surface activity at low
temperature, as seen from the fact that almost all oxidative products can be retrieved for different toluene derivatives and
surfactants by mimicking the conditions of reaction. In the emulsifications of toluene derivatives at 90‡C, the time that
turbid water layers of surfactant solutions take to become clear is the same as that of the catalytic effect on oxidation
of toluene derivatives. Thus, it can be inferred that surfactants can improve the oxidation yields of toluene derivatives
by increasing the contact between two reacting phases. 相似文献
17.
18.
19.
20.
Chunguang Du Hongyi Chen Shiqun Li 《量子光学学报》2006,12(B08):70-71
Recently, research on left-handed materials (LHMs) has attracted considerable attentions. The LHMs are a kind of metameterial which have negative permittivity and negative permeability, which lead to negative refractive index in a frequency range. The LHMs that have been available so far are in the microwave range and are usually composed of classical particles, such as split-ring resonators. Some quantum phenomena such as spontaneous emission of atoms in the LHMs which are considered to be 'classical background' have also been investigated. Many potential applications of LHMs have been proposed, such as superlenses which, in principle, can achieve arbitrary subwavelength resolution. 相似文献