全文获取类型
收费全文 | 98660篇 |
免费 | 4198篇 |
国内免费 | 3386篇 |
专业分类
化学 | 39897篇 |
晶体学 | 1104篇 |
力学 | 7848篇 |
综合类 | 223篇 |
数学 | 34197篇 |
物理学 | 22975篇 |
出版年
2024年 | 62篇 |
2023年 | 440篇 |
2022年 | 683篇 |
2021年 | 778篇 |
2020年 | 890篇 |
2019年 | 941篇 |
2018年 | 11026篇 |
2017年 | 10874篇 |
2016年 | 6982篇 |
2015年 | 1910篇 |
2014年 | 1580篇 |
2013年 | 1984篇 |
2012年 | 5746篇 |
2011年 | 12599篇 |
2010年 | 7097篇 |
2009年 | 7377篇 |
2008年 | 8031篇 |
2007年 | 10073篇 |
2006年 | 1372篇 |
2005年 | 2287篇 |
2004年 | 2348篇 |
2003年 | 2661篇 |
2002年 | 1743篇 |
2001年 | 838篇 |
2000年 | 748篇 |
1999年 | 534篇 |
1998年 | 485篇 |
1997年 | 378篇 |
1996年 | 454篇 |
1995年 | 336篇 |
1994年 | 282篇 |
1993年 | 245篇 |
1992年 | 205篇 |
1991年 | 188篇 |
1990年 | 175篇 |
1989年 | 157篇 |
1988年 | 114篇 |
1987年 | 108篇 |
1986年 | 105篇 |
1985年 | 100篇 |
1984年 | 78篇 |
1983年 | 58篇 |
1982年 | 49篇 |
1981年 | 51篇 |
1980年 | 51篇 |
1979年 | 56篇 |
1914年 | 45篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
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
42.
43.
44.
45.
46.
47.
The structure, chemical composition, and magnetic properties of electrochemically deposited nanocrystalline Co-Ni-Fe films
were investigated using a number of techniques. A high saturation magnetic induction up to B
s
= 21 kG was attained. An enhancement of the saturation magnetization compared to the ideal anticipated one was revealed,
which correlated with the nonlinear behavior of the structural phase composition and lattice parameters with the change of
the composition.
The text was submitted by the authors in English. 相似文献
48.
W. L. Liang B. K. A. Ngoi L. E. N. Lim K. Venkatakrishnan C. W. Hee 《Optics & Laser Technology》2003,35(4):285-290
In this paper, integration of interference phenomenon into femtosecond laser micromachining was reported as the femtosecond laser pulses were reshaped spatially to perform ablation. The generation of circular interference pattern was demonstrated by overlapping infrared femtosecond laser pulses. The interference pattern was subsequently focused on a copper substrate to ablate microstructures of concentric circular rings. The present technique is expected to open up new applications in the areas of rapid fabrication of micro-Fresnel lenses, hybrid microlenses and lens arrays. 相似文献
49.
Bijian Lan Chunming Liu Xiang Yin Hua Zhang Wei Xu Zhongyi Hua 《Frontiers of Chemistry in China》2006,1(3):296-299
Organic materials of D-π-A type MR-X (MR-1: p-dimethylaminophenylethenetrica-rbonitrile and MR-2: p-diphenylaminophenylethene tricarbonitrile) were designed and synthesized. The device with a sandwich structure shows good
rectificative phenomena. The highest rectification ratio 10000 was achieved in device Cu/MR-1/Ag, and about 100 in other device
M/MR-X/M (M: Cu, Ag). It has been found that rectificative phenomena exist only in the atmosphere-liquid interface region
by means of liquid adsorption, and electric field could help form the oriented molecular film.
__________
Translated from Journal of Fudan University (Natural Science), 2005, 44(4) (in Chinese) 相似文献
50.
A forecasting model is developed for the number of daily applications for loans at a financial services telephone call centre. The purpose of the forecasts and the associated prediction intervals is to provide effective staffing policies within the call centre. The model building process is constrained by the availability of only 2 years and 7 months of data. The distinctive feature of the data is that demand is driven in the main by advertising. The analysis given focuses on applications stimulated by press advertising. Unlike previous analyses of broadly similar data, where ARIMA models were used, a model with a dynamic level, multiplicative calendar effects and a multiplicative advertising response is developed and shown to be effective. 相似文献