全文获取类型
收费全文 | 1001篇 |
免费 | 25篇 |
国内免费 | 3篇 |
专业分类
化学 | 490篇 |
晶体学 | 30篇 |
力学 | 33篇 |
数学 | 121篇 |
物理学 | 355篇 |
出版年
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 9篇 |
2020年 | 21篇 |
2019年 | 19篇 |
2018年 | 15篇 |
2017年 | 18篇 |
2016年 | 29篇 |
2015年 | 23篇 |
2014年 | 39篇 |
2013年 | 48篇 |
2012年 | 79篇 |
2011年 | 70篇 |
2010年 | 45篇 |
2009年 | 32篇 |
2008年 | 44篇 |
2007年 | 48篇 |
2006年 | 39篇 |
2005年 | 44篇 |
2004年 | 52篇 |
2003年 | 40篇 |
2002年 | 23篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 14篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 14篇 |
1995年 | 19篇 |
1994年 | 15篇 |
1993年 | 15篇 |
1992年 | 7篇 |
1991年 | 12篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 12篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1973年 | 4篇 |
排序方式: 共有1029条查询结果,搜索用时 15 毫秒
131.
We consider here a treatment of the dipolar plasmon of a small metallic sphere, for which the radial extension of the surface profile is small compared with the radius of the sphere. We obtain the eigenvalues and damping by solving the classical equations for a non-uniform system. The theory is applicable also to the driven response. We compare our results with those recently reported by Apell and Ljungbert. 相似文献
132.
Amarendra Patra Apurba K. Mukhopadhyay Alok K. Mitra 《Magnetic resonance in chemistry : MRC》1981,17(3):166-168
Carbon-13 signal assignments of taraxasteryl acetate, taraxasteryl palmitate, taraxasterol and epi-friedelinyl acetate are reported. Some signal assignments of the friedelanones, reported recently by others, are inconsistent and require revision. 相似文献
133.
S. N. Mukhopadhyay 《Acta Mathematica Hungarica》1966,17(1-2):129-136
134.
The mean field theories of an electron liquid at metallic densities, which go beyond the RPA, and which have been fairly successful so far, are shown to be inadequate when tested against phenomena involving high frequencies. It is also shown that by making a simple Gaussian ansatz for the imaginery part of the response function, χ″(q,ω), and using the zeroth, the first and the third frequency moments of density spectral function to determine the unknown parameters in χ″(q,ω), it is possible to understand at least semiquantitatively the available experimental information regarding the dynamic form factor. Implications of the present analysis as regards the further refinement of the present theories are indicated. 相似文献
135.
Sengupta J Mukhopadhyay R Bhattacharjya A Bhadbhade MM Bhosekar GV 《The Journal of organic chemistry》2005,70(21):8579-8582
3,5'-ether-linked pseudooligopentose derivatives were synthesized for the first time from readily available carbohydrate precursors. The 1,2-isopropylidene-protected ether-linked oligopentoses are potentially important as precursors of novel RNA analogues. Intramolecular cycloaddition of the nitrile oxides prepared from these derivatives led to the diastereoselective formation of chiral isoxazolines fused to 10-16-membered oxacycles. The stereochemistry of some of these isoxazolines was established by X-ray diffraction and NOESY analysis. 相似文献
136.
Bernal I Mukhopadhyay U Virovets AV Fedin VP Clegg W 《Chemical communications (Cambridge, England)》2005,(30):3791-3792
Examination of the crystal structure of the adduct of hydronium tetrachloroferrate dichloride with cucurbituril resulted in the discovery that the hydronium cation present therein is not the well known H7O3+ species; rather, it is an unprecedented cyclic species of composition (H14O6)2+, templated by the formation of five hydrogen bonds to cucurbituril. 相似文献
137.
138.
We present a discussion on the absorptance of electromagnetic radiation per unit length in the surface region of a free electron like metal. We wish particularly to comment on recent work by Feibelman, Kliewer, Forstmann and Stenscke, who all considered different approximations of the jellium model. We are using a unified treatment from which the results in their models can easily be obtained. Our results confirm the general conclusions by Kliewer about a strong coupling to the electron-hole excitations which lead to a locally negative absorptance. In the model considered by Feibelman there is no such coupling to electron-hole excitations and he obtains the classical results for the absorptance. Forstmann and Stenschke have recently applied a hydrodynamical approach which gives results in disagreement with Kliewer's theory as well as with our own results, and we make some comments about their approach. 相似文献
139.
Lalit N. Patnaik M. K. Rout Anuradha Rout Swoyam P. Rout 《Journal of polymer science. Part A, Polymer chemistry》1980,18(1):47-51
In this investigation an approach to correlate the composite rate constants of some redox polymerization reactions [acrylonitrile-Ce(IV)-organic substrate] with a new type of multiparameter equation is described. The multiparameter equation is based on Swain and Lupton's F and R, the field and resonance components of the substituents, respectively, and the unique positional weighting factors f and r suggested by Williams and Norrington. The statistical parameters of the correlation involving the substituent constants (fF and rR) and the rate data have been found to be quite satisfactory, the average coefficient of determination being 0.91. The significance levels of the correlation also indicate that the present model is applicable to the kinetics of redox polymerization. The sign and magnitude of the reaction-dependent regression constants α and β suggest that three different types of reaction mechanisms are operative for the substrates benzaldehyde, phenylthiourea, acetophenone, and toluene. 相似文献
140.
We report the development of a set of spin-adapted creation and annihilation operators which provides a suitable generalisation of the usual many-body apparatus. 相似文献