全文获取类型
收费全文 | 1346篇 |
免费 | 34篇 |
国内免费 | 3篇 |
专业分类
化学 | 859篇 |
晶体学 | 9篇 |
力学 | 51篇 |
数学 | 122篇 |
物理学 | 342篇 |
出版年
2022年 | 11篇 |
2021年 | 12篇 |
2020年 | 9篇 |
2019年 | 26篇 |
2018年 | 12篇 |
2016年 | 26篇 |
2015年 | 21篇 |
2014年 | 29篇 |
2013年 | 34篇 |
2012年 | 64篇 |
2011年 | 64篇 |
2010年 | 26篇 |
2009年 | 39篇 |
2008年 | 65篇 |
2007年 | 48篇 |
2006年 | 69篇 |
2005年 | 51篇 |
2004年 | 42篇 |
2003年 | 39篇 |
2002年 | 33篇 |
2001年 | 23篇 |
2000年 | 28篇 |
1999年 | 16篇 |
1998年 | 14篇 |
1997年 | 13篇 |
1996年 | 20篇 |
1995年 | 23篇 |
1994年 | 14篇 |
1993年 | 21篇 |
1992年 | 35篇 |
1991年 | 21篇 |
1990年 | 19篇 |
1989年 | 26篇 |
1988年 | 10篇 |
1987年 | 21篇 |
1986年 | 19篇 |
1985年 | 22篇 |
1984年 | 33篇 |
1983年 | 22篇 |
1982年 | 20篇 |
1981年 | 26篇 |
1980年 | 18篇 |
1979年 | 17篇 |
1978年 | 20篇 |
1977年 | 19篇 |
1976年 | 9篇 |
1975年 | 23篇 |
1974年 | 12篇 |
1973年 | 17篇 |
1968年 | 7篇 |
排序方式: 共有1383条查询结果,搜索用时 0 毫秒
71.
Hudson BS Braden DA Parker SF Prinzbach H 《Angewandte Chemie (International ed. in English)》2000,39(3):514-516
Vibrational frequencies that are forbidden in Raman and IR absorption can be observed by inelastic neutron scattering. In the case of the I(h)-symmetrical molecule dodecahedrane (shown schematically), the resulting spectrum agrees with a DFT calculation. 相似文献
72.
73.
S.G. Parker 《Solid State Communications》1979,31(6):403-408
Factors which influence coercivity, Hc, in (Y,Sm,Lu,Ca)3(FeGe)5O12 films and in (Y,Sm,Tm)3(FeGa)5O12 films grown by LPE have been identified. An anomalous layer at the film-substrate interface exhibits coercivity values different from that of the middle, bulk, portion of the film. The contribution of the transient layer at the substrate interface could be reduced by increasing the rotation rate while immersing the substrate into the melt. Films containing Ga show lower coercivities than films containing CaGe possibly because films with Ga are more uniform in composition. Films with Ga show increased coercivities with increasing growth rates and with increasing Sm content throughout the film. 相似文献
74.
J.C. Selover Marianne Marsi David W. Parker J.A. Gladysz 《Journal of organometallic chemistry》1981,206(3):317-329
A series of kinetically unstable mononuclear anionic formyl complexes have been prepared by the action of Li(C2H5)3BH on neutral metal carbonyl precursors. One of these, Li+[(CO)4Mn(COC6H5)(CHO)]?, is shown to decompose by a hydride transfer disproportionation mechanism involving the by-product (C2H5)3B. 相似文献
75.
Techniques have been developed which permit the direct analysis of optical purity in α-deuterated amines and carboxylic acids. 相似文献
76.
77.
78.
J.L. Osborne C.A. Barnes R.W. Kavanagh R.M. Kremer G.J. Mathews J.L. Zyskind P.D. Parker A.J. Howard 《Nuclear Physics A》1984,419(1):115-132
Cross sections for the 3He(α, γ)7Be reaction have been measured at several energies from Ec.m. = 165 to 1169 keV by counting prompt γ-rays from a windowless, differentially pumped, recirculating, 3He gas target. The cross-section factor S34(Ec.m.) and branching ratio γ1/γ0 were determined at each energy. Cross sections were also measured at Ec.m. = 947 and 1255 keV by counting the γ-rays from the 7Be produced in a 3He gas cell with a Ni entrance foil. Combining the results of these two independent experiments yields a zero-energy intercept for the cross-section factor of S34(0) = 0.53 ± 0.03 keV · b. The relationship between these measurements and several theoretical calculations, and the import of the extrapolated cross section for the solar-neutrino problem are discussed. 相似文献
79.
The analysis of the interaction of threose 4-phosphate and 2-deoxyerythrose 4-phosphate with 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (DAH7PS) reveals previously unrecognised mechanistic differences between the DAH7PS-catalysed reaction and that catalysed by the closely related enzyme, 3-deoxy-D-manno-octulosonate 8-phosphate synthase (KDO8PS). 相似文献
80.