全文获取类型
收费全文 | 356568篇 |
免费 | 6665篇 |
国内免费 | 5063篇 |
专业分类
化学 | 171841篇 |
晶体学 | 5289篇 |
力学 | 21001篇 |
综合类 | 332篇 |
数学 | 54205篇 |
物理学 | 115628篇 |
出版年
2022年 | 2846篇 |
2021年 | 3752篇 |
2020年 | 3994篇 |
2019年 | 4661篇 |
2018年 | 12662篇 |
2017年 | 13014篇 |
2016年 | 10771篇 |
2015年 | 5017篇 |
2014年 | 7244篇 |
2013年 | 12728篇 |
2012年 | 14593篇 |
2011年 | 22470篇 |
2010年 | 15465篇 |
2009年 | 15793篇 |
2008年 | 19818篇 |
2007年 | 22446篇 |
2006年 | 9917篇 |
2005年 | 13464篇 |
2004年 | 10492篇 |
2003年 | 10061篇 |
2002年 | 8614篇 |
2001年 | 7725篇 |
2000年 | 6024篇 |
1999年 | 4454篇 |
1998年 | 3969篇 |
1997年 | 3781篇 |
1996年 | 3719篇 |
1995年 | 3184篇 |
1994年 | 3338篇 |
1993年 | 3180篇 |
1992年 | 3410篇 |
1991年 | 3548篇 |
1990年 | 3485篇 |
1989年 | 3450篇 |
1988年 | 3272篇 |
1987年 | 3261篇 |
1986年 | 3110篇 |
1985年 | 3743篇 |
1984年 | 3831篇 |
1983年 | 3249篇 |
1982年 | 3185篇 |
1981年 | 3066篇 |
1980年 | 2869篇 |
1979年 | 3350篇 |
1978年 | 3338篇 |
1977年 | 3422篇 |
1976年 | 3542篇 |
1975年 | 3238篇 |
1974年 | 3203篇 |
1973年 | 3381篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
H. Maekawa K. Tsubakihara A. Ohnishi 《The European Physical Journal A - Hadrons and Nuclei》2007,33(3):269-272
We study the hyperon-nucleus potential with distorted-wave impulse wave approximation (DWIA) using the Green's function method.
In order to include the nucleon and hyperon potential effects in Fermi averaging, we introduce the local optimal momentum
approximation of target nucleons. We can describe the quasi-free Λ , Σ and Ξ production spectra in a better way than in the
standard Fermi-averaged t -matrix treatments. 相似文献
992.
We consider a particular case of the matrix Carleman problem for two pairs of functions in a ring and find a constructive
solution of this problem. In addition, we propose an algorithm for the construction of solutions for two infinite systems
of smooth transition and for a system of two singular equations of special type.
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 49, No. 5, pp. 662–671, May, 1997 相似文献
993.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, p. 2899, December, 1991. 相似文献
994.
995.
P. Schuurmans J. Wouters P. De Moor N. Severijns W. Vanderpoorten J. Vanhaverbeke L. Vanneste 《Hyperfine Interactions》1992,75(1-4):423-430
Anisotropic α-emission from nuclei in the decay chain from223Ra to207Tl has been observed using low temperature nuclear orientation in combination with high resolution α-detection at 4.2 K. Information
on partial wave amplitudes as well as hyperfine interactions has been extracted. 相似文献
996.
997.
998.
一类广义维里拉普拉斯,把在白噪声分析构架中通常定义的维里拉普拉斯作为特殊情形而包含。 相似文献
999.
E. Sh. Finkel'shtein N. V. Ushakov N. A. Pritula E. A. Andreev N. A. Platé 《Russian Chemical Bulletin》1992,41(1):185-187
The thermally initiated and platinum-catalyzed polymerization of 1-silacyclobutanes with substitutents containing a trimethylsilyl group was carried out. Soluble, high-molecular-weight, heterochain siltrimethylene polymers were obtained, containing trimethylsilyl groups removed from the main chain by various bridges.A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 117912 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 223–225, January, 1992. 相似文献
1000.
R. Kimmich F. Klammler V. D. Skirda I. A. Serebrennikova A. I. Maklakov N. Fatkullin 《Applied magnetic resonance》1993,4(4):425-440
Geometrical restrictions of water diffusion in different aqueous protein systems were studied using two versions of the NMR field gradient technique. The samples were aqueous systems of bovine serum albumin, gelatin and horse myoglobin at concentrations ranging from diluted solutions to almost dry powders being only partly hydrated. Hydrated protein aerogels were produced by the aid of a special preparation procedure and studied in addition. The experiments referred to the, temperature and concentration dependences of the water diffusion coefficient above and below the free-water freezing temperature. The diffusion coefficient within clusters of overlapping hydration shells is reduced by one order of magnitude compared with that of bulk water. Geometrical restrictions manifest themselves (a) by the obstruction effect observed at low protein concentrations, (b) by the topologically two-dimensional diffusion in the network of overlapping hydration shells, (c) by the percolation threshold appearing at about 15%b.w. water and (d) by the anomalous diffusion behaviour concluded from the protein aerogel study. 相似文献