全文获取类型
收费全文 | 401篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
化学 | 195篇 |
晶体学 | 52篇 |
力学 | 11篇 |
数学 | 12篇 |
物理学 | 134篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 14篇 |
2018年 | 16篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 28篇 |
2012年 | 13篇 |
2011年 | 21篇 |
2010年 | 9篇 |
2009年 | 12篇 |
2008年 | 18篇 |
2007年 | 18篇 |
2006年 | 19篇 |
2005年 | 18篇 |
2004年 | 17篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 10篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 10篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1967年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有404条查询结果,搜索用时 15 毫秒
11.
12.
Alinchenko MG Voloshin VP Medvedev NN Mezei M Pártay L Jedlovszky P 《The journal of physical chemistry. B》2005,109(34):16490-16502
The properties of the interatomic voids present in fully hydrated dimyristoylphosphatidylcholine (DMPC)-cholesterol mixed membranes of different compositions are analyzed in detail using a generalized variant of the Voronoi-Delaunay method on the basis of computer simulation results. The systems investigated are chosen from both sides of the DMPC-cholesterol miscibility gap; the pure DMPC bilayer has also been included in the analysis as a reference system. The results obtained show that the empty space is organized in a more compact way, forming larger voids in the presence than in the absence of cholesterol. The voids located in the region of the rigid cholesterol rings become, on average, less spherical, oriented more parallel with the membrane normal axis with increasing cholesterol concentration, whereas an opposite effect of cholesterol is observed in the middle of the membrane among the chain terminal methyl groups. In general, the preferential orientation of the voids is found to strongly correlate with that of the molecules in the hydrocarbon phase of the membranes. The membranes are found to contain rather large voids, the volume of which can be an order of magnitude larger than the largest spherical cavities present in the systems. These voids are elongated or branching channels rather than big empty holes. The voids located among the DMPC and cholesterol molecules are lying preferably parallel with the membrane normal axis. The existence of such empty channels can be of great importance in the cross-membrane permeation of small, uncharged penetrants, in particular, of polar molecules. 相似文献
13.
V. P. Kazakov A. I. Voloshin S. S. Ostakhov E. V. Zharinova 《Russian Chemical Bulletin》1998,47(3):386-393
Catalysis of decomposition of dispiro(diadamantane-1,2-dioxetane) (1) in the presence of EuIII and TbIII tris(benzoyltrifluoroacetonate) complexes (Ln(btfa)3) accompanied by the formation of adamantanone (2) and chemiluminescence (CL) was studied. The rate constants (k 2) of decomposition of compound1 in the1·Ln(btfa)3 complexes and their stability constants (K 1) have been determined. The Arrhenius parameters of decomposition of1 (E a= 22.4±0.7 kcal mol?1, logA=10.2±0.8 for1·Tb(btfa)3 andE a=23.4±0.6 kcal mol?1, logA=10.6±0.8 for1·Eu(btfa)3) and thermodynamic parameters of complex formation (ΔH=?5.5±0.5 kcal mol?1, ΔS=?10.4±0.7 e.u. for1·Tb(btfa)3 and ΔH=?5.8±0.5 kcal mol?1, ΔS=?10.9±0.7 e.u. for1·Eu(btfa)3) have been calculated from the temperature dependences ofk 2 andK 1. The yields of excitation of the Ln(btfa)3 chelates φ Eu * =0.021±0.006 and φ Tb * =0.12±0.04 have been determined. A higher efficiency of the occupation of the5D4-level of Tb3+ compared to those of the5D1- and5D0-levels of Eu3+ is caused by different efficiencies of the non-radiative energy dissipation in the Ln3+ ion after the intracomplex energy transfer from the3n,π*-state of2 to the resonance excited levels of lanthanides. 相似文献
14.
A. I. Voloshin G. L. Sharipov V. P. Kazakov G. A. Tolstikov 《Russian Chemical Bulletin》1991,40(6):1158-1162
We have investigated chemiluminescence activated by Ru(bpy)3Cl2 in the reaction of decomposition of 1,2-dioxetane. Catalysis and activation of chemiluminescence of 1,2-dioxetanes by a ruthenium complex occur according to a mechanism of chemically initiated electron exchange, which leads to effective excitation of Ru(bpy)3Cl2 with yield
=0.20±0.05.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1316–1321, June, 1991. 相似文献
15.
16.
17.
The splitting of the second maximum of the radial distribution function of an irregular atomic packing is regarded as an indication
of the amorphous state of a substance. This paper describes the splitting-forming atomic configurations using Delaunay simplices,
representing chains of elementary configurations. It is shown that the splitting is formed of chains in which all simplices
are nearly regular tetrahedra and quartoctahedra.
Translated fromZhumal Struktumoi Khimii, Vol. 38, No. 1, pp. 78–88, January–February, 1997. 相似文献
18.
N. A. Voloshin A. V. Chernyshev A. V. Metelitsa I. M. Raskita E. N. Voloshina V. I. Minkin 《Russian Chemical Bulletin》2005,54(3):705-710
The reaction of 2-hydroxy-3-(4,5-diphenyl-1,3-oxazol-2-yl)-1-naphthaldehyde with 1,2,3,3-tetramethyl-3H-indolium perchlorate afforded photochromic spiro[indoline-2,3′-naphthopyran] containing a 4,5-diphenyloxazole group in position 5′ of the naphthopyran fragment. The merocyanine form of the spiropyran gave complexes with bivalent heavy cations.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 693–697, March, 2005. 相似文献
19.
20.
G. L. Bochek V. K. Voloshin O. S. Deiev N. I. Maslov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2013,7(2):339-346
The interaction between X-ray radiation and the material of secondary targets is simulated using GEANT4 for two methods of measurements of intense X-ray spectra. In the first case, characteristic X-ray radiation (CXR) from the secondary target to the back hemisphere is detected; in the second case, primary radiation passing through pairs of foils (a Ross filter) is registered. Using Ross filters and the CXR technique, the primary spectra of X-ray radiation are recovered. Two methods for recovery primary radiation spectra are compared. 相似文献