全文获取类型
收费全文 | 457篇 |
免费 | 130篇 |
国内免费 | 61篇 |
专业分类
化学 | 205篇 |
晶体学 | 12篇 |
力学 | 9篇 |
综合类 | 7篇 |
数学 | 14篇 |
物理学 | 401篇 |
出版年
2023年 | 4篇 |
2022年 | 14篇 |
2021年 | 10篇 |
2020年 | 33篇 |
2019年 | 16篇 |
2018年 | 18篇 |
2017年 | 22篇 |
2016年 | 21篇 |
2015年 | 15篇 |
2014年 | 31篇 |
2013年 | 46篇 |
2012年 | 25篇 |
2011年 | 20篇 |
2010年 | 32篇 |
2009年 | 26篇 |
2008年 | 23篇 |
2007年 | 31篇 |
2006年 | 27篇 |
2005年 | 21篇 |
2004年 | 29篇 |
2003年 | 18篇 |
2002年 | 23篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 22篇 |
1998年 | 24篇 |
1997年 | 16篇 |
1996年 | 17篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有648条查询结果,搜索用时 31 毫秒
601.
利用Dirac-Slater相对论平均自洽场理论,研究了类氖铁离子Fe16+(1s22s22p6)与自由电子的辐射复合(RR)截面,在分析相对论量子数的取值范围及原子模型等对n壳层RR截面的影响的基础上,给出了n壳层RR截面随自由电子能量变化的一般规律. 相似文献
602.
The KLL dielectronic recombination processes for highly charged krypton, iodine and barium ions
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The KLL dielectronic recombination (DR) processes of
ions from highly charged helium-like to oxygen-like krypton, iodine
and barium ions are studied systematically in the relativistic
distorted-wave approximation with configuration interaction. The KLL
DR resonant energies, the corresponding resonant strengths and the
theoretical spectra for each highly charged ion species are
obtained. The results accord well with other available values. The
behaviour of KLL resonant strengths for He-like ions with atomic
number Z is analysed. 相似文献
603.
The donor-acceptor interface plays a critically important role in determining the power conversion efficiency of organic solar cells via controlling charge separation (CS) and recombination (CR) processes. Here, we combine the electronic structure calculations with electron transfer rate theory to clarify the CS and CR processes in ThQs-C60 /PDIxCN2 donor-acceptor complexes. The results reveal that in ThQs-PDIxCN2 the CS comes from both the dissociations of photo-induced singlet exciton and singlet fission-induced triplet exciton with a high efficiency, whereas in ThQs-C60 only the singlet exciton dissociation can take place because the triplet exciton lies below the charge-transfer exciton. However, very high CR rates in ThQs-PDIxCN2 obliterate the benefit of fast CS, inversely leading to the ThQ-C60 complex with a better cell efficiency. The present results are consistent with experimental observation and may furnish a possible patten to improve the overall conversion efficiency. © 2018 Wiley Periodicals, Inc. 相似文献
604.
近年来有机-无机金属卤化物钙钛矿太阳能电池因具有光电能量转换效率高、制备工艺简单等优点,引起了学术界和产业界的广泛关注,其优异的光电特性逐渐在能源领域展现出独特的优越特性.在短短几年内,有机-无机混合物钙钛矿太阳能电池的能量转换效率已经高达23%,发展速度逐步赶上甚至超越了成熟的硅太阳能电池.本文利用飞秒瞬态吸收光谱,对二步法制备的(5-AVA)_(0.05)(MA)_(0.95)PbI_3和(5-AVA)_(0.05)(MA)_(0.95)PbI_3/Spiro-OMeTAD有机-无机卤化物钙钛矿薄膜材料的激发态动力学进行了对比研究,详细讨论了两种薄膜样品中的电荷载流子产生与复合机制.通过紫外-可见吸收光谱测得钙钛矿薄膜(5-AVA)_(0.05)(MA)_(0.95)PbI_3和(5-AVA)_(0.05)(MA)_(0.95)PbI_3/Spiro-OMeTAD的吸收光谱与CH_3NH_3PbI_3钙钛矿薄膜材料的双价带结构相对应.从瞬态吸收光谱中,观察到760 nm附近的光致漂白信号,此时的载流子复合过程符合二阶动力学过程,而在约550—700 nm光谱范围内则是光诱导激发态吸收信号.实验结果表明,(5-AVA)_(0.05)(MA)_(0.95)PbI_3钙钛矿薄膜样品中光生载流子主要的弛豫途径是自由电子和空穴的复合.抽运光激发样品使价带中的电子跃迁到导带,随着延迟时间的增加,电子和空穴复合,光谱发生红移现象.所观察到的带重整效应可以根据Moss-Burstein效应解释.相比较而言,(5-AVA)_(0.05)(MA)_(0.95)PbI_3/Spiro-OMeTAD钙钛矿薄膜样品在光激发后电子和空穴分离,空穴迅速转移到空穴传输层,这将导致样品吸收度增加,漂白信号快速恢复,电子-空穴的复合不再对漂白信号的弛豫动力学起主导作用,同时也削弱了带重整现象.本文的实验结果对半导体有机-无机金属卤化物钙钛矿薄膜在光伏领域的应用具有重要意义,为今后高效、稳定的钙钛矿太阳电池的研究提供了参考. 相似文献
605.
在光催化分解水产氢的过程中,Pt等助催化剂在催化产生氢的同时也会诱导催化氢气和氧气重新复合为水的逆反应,严重降低了悬浮体系光催化全分解水产氢的效率。本文综述了近年来在逆反应抑制方面的研究进展,总结和对比分析了各种抑制逆反应策略的特点,并对这些方法的应用于悬浮体系光催化全分解水制氢的前景进行了展望。 相似文献
606.
XIANG Yan ZHUANG Jia MA Zhu LU Honglin XIA Haoran ZHOU Weiya ZHANG Tao LI Haimin 《高等学校化学研究》2019,35(1):101-108
Mesoporous scaffold structures have played great roles in halide perovskite solar cells(PSCs),due to the excellent photovoltaic performance and commercial perspective of mesoporous PSCs.Here,we reported a mixed-phase TiO2 mesoporous film as an efficient electron transport layer(ETL)for mesoporous perovskite solar cells.Due to the improved crystal phase,fihn thickness and nanopartMe size of TiO2 layer,which were controlled by varying the one-step hydrothermal reaction time and annealing time,the PSCs exhibited an outstanding short circuit photocurrent density of 25.27 mA/cm^2,and a maximum power conversion efficiency(PCE)of 19.87%.It is found that the ultra-high Jsc attributes to the excellent film quality,light capturing and excellent electron transport ability of mixed-phase TiO2 mesoporous film.The results indicate that mix-phase mesoporous metal oxide fihns could be a promising candidate for producing effective ETLs and high efficiency PSCs. 相似文献
607.
The influence from high-n dielectronic satellites to Kɑ resonance line in helium-like aluminium
下载免费PDF全文
![点击此处可从《中国物理》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Based on the multi-configuration Dirac-Fock method, this paper has made theoretical calculations for the dielectronic recombination cross-sections and the high-n dielectronic satellites to Kα resonance line in helium-like aluminium ions. It is found that high-n dielectronic satellites are seriously mixed with resonance line, which leads to a significant increase in both the apparent width and the intensity of Kα resonance line. They also induce a positional shift of Kα resonance line. 相似文献
608.
James A. McLennan 《Journal of statistical physics》1989,57(3-4):887-905
The incorporation of three-body collisions for dissociation/recombination into the Boltzmann equation is discussed. Conditions are assumed such that collisions are completed in the sense of scattering theory, so the collision operator is determined by scattering and reaction cross sections. The resulting equation has anH-theorem, and the equilibrium solution requires the law of mass action in addition to the Maxwellian dependence on momentum. A brief discussion is given of the normal solution and the transport coefficients.This paper is dedicated to Prof. E. G. D. Cohen on the occasion of his 65th birthday. 相似文献
609.
电子碰撞激发机制中自电离与双电子俘获 总被引:1,自引:1,他引:0
以Ge为例,研究了双电子复合代替自电离与双电子俘获对离子布居的影响;通过解包括双激发态和自电离与双电子俘获过程的速率方程组,研究了类F离子与类Ne离子基态对19.6nm与23.6nm激光线上、下能级的布居贡献因子及类Na离子与类Ne离子的电离速率,并讨论了这两条激光线的反转与增益。 相似文献
610.
We first recall the main linear optical properties of semiconductor-doped glasses in the strong confinement regime. We then discuss the origin of the photodarkening effect and its consequences on the luminescence and absorption spectra. Photodarkening and, at high excitation intensity, Auger processes strongly modify carrier recombination as studied by time-resolved luminescence measurements. This is further supported by using nonlinear optical techniques such as optical phase conjugation. We finally recall the origin of the nonlinear response of such media in the resonant regime and the size dependence of the corresponding figure of merit. 相似文献