全文获取类型
收费全文 | 862篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
化学 | 314篇 |
晶体学 | 4篇 |
力学 | 22篇 |
数学 | 80篇 |
物理学 | 449篇 |
出版年
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 9篇 |
2013年 | 32篇 |
2012年 | 19篇 |
2011年 | 39篇 |
2010年 | 24篇 |
2009年 | 15篇 |
2008年 | 28篇 |
2007年 | 29篇 |
2006年 | 27篇 |
2005年 | 27篇 |
2004年 | 18篇 |
2003年 | 19篇 |
2002年 | 28篇 |
2001年 | 26篇 |
2000年 | 12篇 |
1999年 | 15篇 |
1998年 | 11篇 |
1997年 | 16篇 |
1996年 | 23篇 |
1995年 | 30篇 |
1994年 | 24篇 |
1993年 | 19篇 |
1992年 | 26篇 |
1991年 | 17篇 |
1990年 | 15篇 |
1989年 | 21篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 15篇 |
1985年 | 11篇 |
1984年 | 10篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 12篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 13篇 |
1976年 | 15篇 |
1975年 | 10篇 |
1974年 | 12篇 |
1973年 | 10篇 |
1972年 | 9篇 |
1969年 | 6篇 |
1938年 | 5篇 |
排序方式: 共有869条查询结果,搜索用时 0 毫秒
1.
2.
This paper provides exact and rigorous upper and lower bounds to the ground state energy of the Single Impurity Anderson Model in the limit of infiniteU. The upper bound approximates the ground state energy very well and the corresponding state may be used as a starting point for further investigations. The energy spectrum of the Single Impurity Anderson Model is calculated exactly for a special non-trivial model density of states describing the bare band electrons. All approaches introduced here are compared to this exact result and to other ground state energy calculations. 相似文献
3.
F. T. Brandt G. Kramer Su-Long Nyeo 《Zeitschrift fur Physik C Particles and Fields》1990,48(2):301-308
We calculate cross sections for the production ofW + andZ bosons in association with 1 and 2 jets at \(p\bar p\) collider energies. The expected rates for these processes in second-order QCD are presented as a function of the cuts on the transverse momenta of the jets and are compared with jet rates measured by UA1. 相似文献
4.
5.
N. B. Brandt Zh. T. Ismailov V. A. Kul'bachinskii S. A. Lapin S. M. Chudinov 《Russian Physics Journal》1989,32(11):889-898
A new method is proposed for determining the magnetic characteristics (magnitude and sign of the exchange interaction energy and the average size of clusters of magnetic ions) of dilute solid solutions of semimagnetic semiconductors at low temperatures based on oscillation measurements. The method makes it possible to find the magnetic characteristics of the indicated systems at temperatures between the point of the transition into the spin glass state and the temperature corresponding to the characteristic binding energy of magnetic atoms in clusters, for which standard methods based on the measurement of the magnetic susceptibility are not effective. The method is used to study the character of the exchange interaction in the system of solid solutions Hg1–xMnxSe as a function of their composition as well as under conditions of hydrostatic compression. To this end the oscillations of the magnetoresistance (Shubnikov-de Haas (SH) effect) in single-crystalline samples of Hg1–xMnxSe in the region of compositions 0.001 x 0.23 in magnetic fields H up to 65 kOe at temperatures T = (0.4–20) K and pressures up to 16 kbar were studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 29–39, November, 1989. 相似文献
6.
7.
An effective total synthesis of (-)-callystatin A (1), member of the leptomycin family of antibiotics, has been achieved. The synthesis features Evans extended aldol methodology to construct the northern polypropionate subunit and two separate Julia olefinations to assemble the conjugated dienes. The total synthesis proceeded in 2.3% overall yield with the longest linear sequence of 15 steps. 相似文献
8.
Reinhard Brandt 《Angewandte Chemie (International ed. in English)》1971,10(12):890-900
In this review paper, ternary fission is defined as the break-up of heavy nuclei into three fragments of approximately equal mass. This relatively new type of nuclear decay has been investigated intensively during the last decade. Muga has studied ternary fission induced by thermal neutrons in uranium. The results of his experiments are discussed in detail. Ternary fission can definitely be observed and studied in the interaction of heavy target elements with 39 MeV alpha particles, 20 GeV protons, and 300—400MeV argon ions. The ratio of binary-to-binary fission for uranium is approximately 10?4: 100 in the interaction of 39 MeV alpha particles, approximately 0.1:100 for 20 GeV protons, and 3:100 for 400MeV argon ions. A theoretical model for the interpretation of ternary fission, the “cascade model”, is described. The paper concludes with a discussion of the possible connection of ternary fission with the production and decay of still undiscovered super-heavy elements (Z = 114). 相似文献
9.
M. W. Brandt J. E. Mulvaney H. K. Hall G. D. Green 《Journal of polymer science. Part A, Polymer chemistry》1989,27(6):1957-1965
7,8-Dicyano-7,8-diphenylquinodimethane (DCDPQ) was prepared by oxidation of the dianion of α,α′-dicyano-α,α′-diphenylxylene. 1H-NMR of a solution of the purified compound showed that the cis and trans isomers were present in a 1:1 ratio. Following further spectroscopic and electronic characterization the polymerizability of the title compound was investigated. DCDPQ did not homopolymerize at 65°C in the presence of AIBN. DCDPQ copolymerized with p-methoxystyrene and p-aminostyrene in the presence of AIBN at 65°C. Characterization of the latter two copolymers indicated that they were nearly alternating. The copolymerization between DCDPQ and p-aminostyrene proceeded in the absence of AIBN. 相似文献
10.