全文获取类型
收费全文 | 576篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
化学 | 379篇 |
晶体学 | 4篇 |
力学 | 5篇 |
数学 | 62篇 |
物理学 | 132篇 |
出版年
2016年 | 7篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 21篇 |
2012年 | 17篇 |
2011年 | 23篇 |
2010年 | 8篇 |
2009年 | 9篇 |
2008年 | 21篇 |
2007年 | 13篇 |
2006年 | 26篇 |
2005年 | 22篇 |
2004年 | 16篇 |
2003年 | 14篇 |
2002年 | 14篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 13篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 16篇 |
1989年 | 5篇 |
1988年 | 9篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 10篇 |
1982年 | 7篇 |
1981年 | 12篇 |
1980年 | 11篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 14篇 |
1976年 | 13篇 |
1975年 | 7篇 |
1974年 | 15篇 |
1973年 | 8篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1905年 | 6篇 |
1900年 | 5篇 |
1891年 | 4篇 |
1890年 | 5篇 |
1888年 | 4篇 |
排序方式: 共有582条查询结果,搜索用时 31 毫秒
81.
82.
Frank D. Blum Jane E. Dickson Wilmer G. Miller 《Journal of Polymer Science.Polymer Physics》1984,22(2):211-221
The effect of diluents and temperature on segmental motion in poly(vinyl acetate) was investigated by both NMR and ESR spectroscopy. Three classes of diluents were studied: chloroform, a thermodynamically good solvent; water, a poor solvent which slightly swells the polymer and lowers its glass transition temperature; and decane, a nonsolvent so poor it does not appear to swell the polymer nor lower the calorimetric glass transition temperature. At all temperatures investigated each type of diluent increased the segmental motion of the polymer over that of the bulk sample. Under the conditions studied, 13C and 2H NMR and nitroxide spin-label ESR data gave similar views of segmental motion of the polymer, indicating that in this amorphous polymer the segmental motion of the polymer may be safely inferred from spin-label data. 相似文献
83.
84.
85.
86.
Omar Elmalak Mordecai Rabinovitz Jochanan Blum 《Journal of heterocyclic chemistry》1993,30(1):291-292
K-Region oxides and imines of phenanthrene, chrysene benz[a]anthracene, and dibenz[a,h]anthracene react in tetrahydrofuran with lithium and sodium to give the parent hydrocarbons. In the presence of excessive metal, the latter are converted into dianions from which the parent compounds can be regenerated upon quenching with oxygen. Metalate derivatives of the oxides and imines are proposed to be the corresponding reaction intermediates in the deoxygenation and deamination processes. 相似文献
87.
It is shown that the solution of the mean spherical approximation for the ion-dipole mixtures obtained by Blum, Adelman, and Deutch has an explicit closed form solution which is one of the roots of a cubic equation. 相似文献
88.
L. Görlich B. Niczyporuk M. Różańska K. Rybicki J. Turnau H. Becker G. Blanar W. Blum H. Dietl J. Gallivan B. Gottschalk E. Lorenz G. Lütjens G. Lutz W. Männer D. Notz R. Richter J. De Groot 《Nuclear Physics B》1980,174(1):16-44
The reaction π?p→K+K?n has been studied on a hydrogen target (27 000 events) at 18.4 GeV/c and on a polarized target (54 000 events) at 17.2 GeV/c. A combination of results of both experiments allows a partial-wave analysis of the K+K? system between 1.1 and 1.74 GeV mass without any model assumptions. In general our fits yield unique solutions. Using results of our previous analysis of π+π? final states and assuming the dominance of the positive G-parity states in the K+K? system, the branching ratios of partial waves into are determined. The S-wave appears to be mainly a broad ε (1300) with . The weak P-wave can be described by a tail of the . The D-wave is interpreted in terms of a superposition of f(1270) + A2(1310) + f′(1515) resonances. The fit yields for the f(1270) and BR(ππ/all) = 0.027?0.013+0.071 for the f′(1515). The F-wave shows the g(1690) meson with . All the above values refer to the t bin between 0.01 and 0.20 (GeV/c)2. Some results are also given for the high-t region. 相似文献
89.
13C NMR spectroscopy was used for the unequivocal analysis of the mixture of products of RuCl2[P(C6H5)3]3-catalysed transfer deuteriation of benzylideneacetophenone by (a) DCOONa/H2O, (b) HCOONa/D2O and (c) DCOONa/D2O. Signal assignments in the 13C spectra were obtained mainly from the deuterium-induced 13C isotope shifts. The geminal 13C? 2H shift of the β-carbon of deuteriated 1,3-diphenylpropan-1-one is almost twice that for the α-carbon. 相似文献
90.
We consider the polarisation properties of light emitted by heavy atoms after excitation by polarised electrons. It is discussed what information on spin-dependent forces can be obtained from the measurements. 相似文献