全文获取类型
收费全文 | 702篇 |
免费 | 21篇 |
国内免费 | 3篇 |
专业分类
化学 | 510篇 |
晶体学 | 5篇 |
力学 | 4篇 |
数学 | 40篇 |
物理学 | 167篇 |
出版年
2022年 | 8篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2017年 | 4篇 |
2016年 | 19篇 |
2015年 | 13篇 |
2014年 | 15篇 |
2013年 | 20篇 |
2012年 | 36篇 |
2011年 | 45篇 |
2010年 | 25篇 |
2009年 | 25篇 |
2008年 | 30篇 |
2007年 | 35篇 |
2006年 | 44篇 |
2005年 | 27篇 |
2004年 | 23篇 |
2003年 | 18篇 |
2002年 | 20篇 |
2001年 | 10篇 |
2000年 | 18篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 13篇 |
1994年 | 14篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 18篇 |
1984年 | 18篇 |
1983年 | 5篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 11篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1973年 | 12篇 |
1971年 | 4篇 |
1967年 | 3篇 |
1965年 | 4篇 |
排序方式: 共有726条查询结果,搜索用时 0 毫秒
81.
82.
We propose a novel analysis method of ab initio molecular dynamics (AIMD) simulation using a continuous wavelet transform (c-WT) technique. The c-WT technique, one of the time-frequency signal analysis methods, provides a clear view of the dynamical information in time developments. Combined with the auto-correlation function of velocity by AIMD simulation, c-WT analysis enables us to well understand dynamical distribution, such as the vibrational properties following a change of electronic structure in a molecular system. As a practical application, AIMD simulation of core-excited BF(3) (B1s --> 2a(2) (')) is illustrated. AIMD simulation leads to the change of vibrational motion as well as structural deformation by core-excitation. The c-WT analysis clarifies the relationship between structural deformation and the related significant vibrational modes in core-excitation within 50 fs. 相似文献
83.
Gasanov R Aliyeva S Arao S Ismailova A Katsuta N Kitade H Yamada S Kawamori A Mamedov F 《Journal of photochemistry and photobiology. B, Biology》2007,86(2):160-164
Water splitting activity, the multiline EPR signal associated with S(2)-state of the CaMn(4)-cluster and the fast and slow phases of the induction curve of the millisecond delayed chlorophyll fluorescence from photosystem II (PSII) in the pH range of 4.5-8.5 were studied in the thylakoid membranes and purified PSII particles. It has been found that O(2) evolution and the multiline EPR signal were inhibited at acidic (pK approximately 5.3) and alkaline (pK approximately 8.1) pH values, and were maximal at pH 6.0-7.0. Our results indicate that the loss of O(2) evolution and the S(2)-state multiline EPR signal associated with the decrease of the millisecond delayed chlorophyll fluorescence only in alkaline region (pH 7.0-8.5). Possible correlations of the millisecond delayed chlorophyll fluorescence components with the donor side reactions in PSII are discussed. 相似文献
84.
85.
Katsuya Oji Asako Igashira‐Kamiyama Nobuto Yoshinari Takumi Konno 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(7):2023-2027
A novel AuICoIII coordination system that is derived from the newly prepared [Co(D ‐nmp)2]− ( 1 −; D ‐nmp=N‐methyl‐D ‐penicillaminate) and a gold(I) precursor AuI is reported. Complex 1 − acts as a sulfur‐donating metallaligand and reacts with the gold(I) precursor to give [Au2Co2(D ‐nmp)4] ( 2 ), which has an eight‐membered AuI2CoIII2 metallaring. Treatment of 2 with [Au2(dppe)2]2+ (dppe=1,2‐bis(diphenylphosphino)ethane) leads to the formation of [Au4Co2(dppe)2(D ‐nmp)4]2+ ( 3 2+), which consists of an 18‐membered AuI4CoIII2 metallaring that accommodates a tetrahedral anion (BF4−, ClO4−, ReO4−). In solution, the metallaring structure of 3 2+ is readily interconvertible with the nine‐membered AuI2CoIII metallaring structure of [Au2Co(dppe)(D ‐nmp)2]+ ( 4 +); this process depends on external factors, such as solvent, concentration, and nature of the counteranion. These results reveal the lability of the Au S and Au P bonds, which is essential for metallaring expansion and contraction. 相似文献
86.
87.
Nakai I Kondoh H Amemiya K Nagasaka M Shimada T Yokota R Nambu A Ohta T 《The Journal of chemical physics》2005,122(13):134709
The mechanism of CO oxidation reaction on oxygen-precovered Pt(111) surfaces has been studied by using time-resolved near-edge x-ray absorption fine structure spectroscopy. The whole reaction process is composed of two distinct paths: (1) a reaction of isolated oxygen atoms with adsorbed CO, and (2) a reaction of island-periphery oxygen atoms after the CO saturation. CO coadsorption plays a role to induce the dynamic change in spatial distribution of O atoms, which switches over the two reaction paths. These mechanisms were confirmed by kinetic Monte Carlo simulations. The effect of coadsorbed water in the reaction mechanism was also examined. 相似文献
88.
Shigenori Kashimura Yoshiyuki Tane Yoshihiro Murai Tomohiro Nakai Ryuich Hirose 《Tetrahedron letters》2008,49(2):269-271
Reduction of dichlorosilanes with Mg metal in the presence of Lewis acid and LiCl was found to be the highly practical method for the synthesis of polysilanes. 相似文献
89.
A new method to remove water adsorbed on flouride glass preforms is reported. This method, using NF3 plasma, can remove surface water on fluoride glasses 相似文献
90.