全文获取类型
收费全文 | 1942篇 |
免费 | 55篇 |
国内免费 | 6篇 |
专业分类
化学 | 1093篇 |
晶体学 | 8篇 |
力学 | 37篇 |
数学 | 315篇 |
物理学 | 550篇 |
出版年
2022年 | 17篇 |
2021年 | 50篇 |
2020年 | 40篇 |
2019年 | 43篇 |
2018年 | 55篇 |
2017年 | 46篇 |
2016年 | 59篇 |
2015年 | 49篇 |
2014年 | 67篇 |
2013年 | 101篇 |
2012年 | 110篇 |
2011年 | 120篇 |
2010年 | 92篇 |
2009年 | 68篇 |
2008年 | 86篇 |
2007年 | 83篇 |
2006年 | 78篇 |
2005年 | 77篇 |
2004年 | 71篇 |
2003年 | 55篇 |
2002年 | 49篇 |
2001年 | 36篇 |
2000年 | 38篇 |
1999年 | 22篇 |
1998年 | 10篇 |
1997年 | 15篇 |
1996年 | 33篇 |
1995年 | 14篇 |
1994年 | 22篇 |
1993年 | 13篇 |
1992年 | 14篇 |
1991年 | 12篇 |
1990年 | 15篇 |
1989年 | 16篇 |
1988年 | 11篇 |
1987年 | 22篇 |
1986年 | 23篇 |
1985年 | 13篇 |
1984年 | 10篇 |
1983年 | 15篇 |
1982年 | 13篇 |
1981年 | 14篇 |
1979年 | 13篇 |
1978年 | 14篇 |
1977年 | 14篇 |
1976年 | 16篇 |
1975年 | 14篇 |
1974年 | 9篇 |
1973年 | 10篇 |
1970年 | 11篇 |
排序方式: 共有2003条查询结果,搜索用时 156 毫秒
71.
Iren Korondán wolfgang Linert Gerhard Gritzner Viktor Gutmann 《Monatshefte für Chemie / Chemical Monthly》1979,110(1):223-234
Based on conductivity measurements, the dissociation of tetraalkylam-moniumhexacyanoferrates(III) in water, ethanol, formamide,N-methylformamide,N,N-dimethylformamide, propylenecarbonate and acetonitrile is discussed. Interactions of the solvent as donor and as acceptor, the latter interaction being dominant, with (et
4N)3Fe(CN)6 and (bu
4N)3Fe(CN) were found to be important factors in the formation of solvated ions. 相似文献
72.
M. ihova M. Hruovsky J. Voitko K. I. Matveev 《Reaction Kinetics and Catalysis Letters》1981,16(4):383-386
In the presence of the catalytic system (PdSO4+HPA), where HPA=H9PMo6V6O40, octene-1 is found to be selectively (95%) oxidized to octanone-2. The optimum concentration ratio for catalyst stability is [HPA]:[PdSO4]=30–40. The substitution of PdCl2 for PdSO4 leads to the formation of all three isomeric octanones without decrease of the overall selectivity. Effective rate constants and the apparent activation energy have been determined in the temperature range from 60 to 80 °C.
(PdSO4+), =H9PMo6V6O40, -1 ( 95%) -2. []:[PdSO4]=30–40. PdSO4 PdCl2 . 60–80 °C.相似文献
73.
Lin JF Militzer B Struzhkin VV Gregoryanz E Hemley RJ Mao HK 《The Journal of chemical physics》2004,121(17):8423-8427
The melting curve of H(2)O has been measured by in situ Raman spectroscopy in an externally heated diamond anvil cell up to 22 GPa and 900 K. The Raman-active OH-stretching bands and the translational modes of H(2)O as well as optical observations are used to directly and reliably detect melting in ice VII. The observed melting temperatures are higher than previously reported x-ray measurements and significantly lower than recent laser-heating determinations. However, our results are in accord with earlier optical determinations. The frequencies and intensities of the OH-stretching peaks change significantly across the melting line while the translational mode disappears altogether in the liquid phase. The observed OH-stretching bands of liquid water at high pressure are very similar to those obtained in shock-wave Raman measurements. 相似文献
74.
Toda lattice equation is represented in the form of the condition of compatibility of the system of linear equations corresponding to a non-Hermitian Lax representation. The Darboux invariance of this linear system is defined and proved in the text, and enables us to construct some new formulas for the solutions of the Toda lattice equation. These formulas involving determinants are applicable to an arbitrary initial solution of the Toda equation for example to a solution growing at infinity.Physique Mathématique et Théorique, Equipe de recherche associée au CNRS.This work has been done as part of the program Recherche Cooperative sur Programme No. 264: Etude interdisciplinaire des problèmes inverses.Leningrad State University, U.S.S.R. 相似文献
75.
76.
Dr. Jaroslav Malina Dr. Olga Novakova Prof. Dr. Giovanni Natile Prof. Dr. Viktor Brabec 《化学:亚洲杂志》2012,7(5):1026-1031
The PtII-coordination complex [PtCl2(DAB)] (DAB=2,3-diaminobutane) belongs to a class of cytotoxic cisplatin analogues that contain chiral diamine ligands. Enantiomeric pairs of these compounds have attracted particular interest because they have different effects on different DNA conformations, which, in turn, influences the binding of damaged-DNA-processing enzymes that control downstream effects of the adducts, and thus exhibit different biological activities of the enantiomers. Herein, we studied the translesion synthesis across the major 1,2-d(GG) intrastrand cross-link formed by the R,R and S,S enantiomers of [Pt(DAB)]2+ in the TGGT sequence by using the enzyme that catalyzes the polymerization of deoxyribonucleotides into a DNA strand. We also employed differential scanning calorimetry (DSC) to measure the thermodynamic changes associated with replication-bypass past 1,2-d(GG) adducts of the [Pt(DAB)]2+ enantiomers. In the sequence TGGT, the 1,2-d(GG) intrastrand cross-links that were formed by the enantiomeric pairs of [Pt(DAB)]2+ inhibited DNA polymerization in a chirality-dependent manner. The thermodynamic data helped to understand the effect of the alterations in thermodynamic stability of DNA caused by the Pt-d(GG) adducts upon DNA polymerization across these lesions. Moreover, these data can possibly explain the influence of these alterations on the ability of many DNA polymerases to bypass adducts of antitumor platinum drugs. These results also highlighted the usefulness of DSC in evaluating the impact of DNA adducts of platinum-coordinated compounds on the processing of these lesions by damaged-DNA processing-enzymes. 相似文献
77.
78.
Steva Lević Nina Obradović Vladimir Pavlović Bojana Isailović Ivana Kostić Miodrag Mitrić Branko Bugarski Viktor Nedović 《Journal of Thermal Analysis and Calorimetry》2014,118(2):661-668
In this study, polyvinyl alcohol (PVA) nanofibers with ethyl vanillin as an active compound were prepared using electrospinning technique. The final products of electrospinning process were in the form of nanofibers films. PVA/ethyl vanillin nanofibers, having fibers diameters in the range 100–1700 nm, were successfully electrospun from ethanol/water mixture of PVA and ethyl vanillin. The effects of immobilization process on ethyl vanillin thermal properties were investigated by differential scanning calorimetry (DSC). The results of DSC showed significant influence of immobilization process on thermal properties of ethyl vanillin. It was noticed that melting point of immobilized ethyl vanillin was lower (~55 °C) compared to free flavor (~77 °C). Our results showed that films based on PVA/ethyl vanillin nanofibers are mechanically stable. 相似文献
79.
Adrian Hernandez Santiago Salvador Rosas Castilla Albino Morales Rodriguez Elena Aleskerova Anastasia Lantushenko Viktor Kostjukov 《Molecular physics》2013,111(15):1941-1947
An approximately linear correlation has been found between the enthalpy of complexation and the area of overlap of the chromophores using published structural and thermodynamical data on the self- and hetero-association of aromatic molecules measured under similar solution conditions. This finding is consistent with the assumption that short-range van-der-Waals forces dominate over other contributions to the enthalpy of stacking of aromatic molecules. It provides a ‘model-independent’ approach for a priori estimation of the enthalpy of aromatic–aromatic stacking interactions from knowledge of the structural properties or vice versa. 相似文献
80.
Matveev Vladimir B. Semenov-Tian-Shansky Michel 《Letters in Mathematical Physics》2019,109(6):1269-1270
Letters in Mathematical Physics - 相似文献