全文获取类型
收费全文 | 398543篇 |
免费 | 5414篇 |
国内免费 | 1444篇 |
专业分类
化学 | 218254篇 |
晶体学 | 5825篇 |
力学 | 16559篇 |
综合类 | 12篇 |
数学 | 46274篇 |
物理学 | 118477篇 |
出版年
2020年 | 2462篇 |
2019年 | 2406篇 |
2018年 | 2423篇 |
2016年 | 4759篇 |
2015年 | 3952篇 |
2014年 | 5375篇 |
2013年 | 17290篇 |
2012年 | 12937篇 |
2011年 | 16227篇 |
2010年 | 10063篇 |
2009年 | 9911篇 |
2008年 | 14898篇 |
2007年 | 15160篇 |
2006年 | 14843篇 |
2005年 | 13753篇 |
2004年 | 12313篇 |
2003年 | 10935篇 |
2002年 | 10690篇 |
2001年 | 12167篇 |
2000年 | 9381篇 |
1999年 | 7511篇 |
1998年 | 6154篇 |
1997年 | 5977篇 |
1996年 | 5991篇 |
1995年 | 5559篇 |
1994年 | 5173篇 |
1993年 | 4995篇 |
1992年 | 5599篇 |
1991年 | 5440篇 |
1990年 | 5089篇 |
1989年 | 4934篇 |
1988年 | 5194篇 |
1987年 | 4920篇 |
1986年 | 4727篇 |
1985年 | 6802篇 |
1984年 | 6930篇 |
1983年 | 5676篇 |
1982年 | 6308篇 |
1981年 | 6209篇 |
1980年 | 5980篇 |
1979年 | 6055篇 |
1978年 | 6208篇 |
1977年 | 6121篇 |
1976年 | 6087篇 |
1975年 | 5916篇 |
1974年 | 5653篇 |
1973年 | 5925篇 |
1972年 | 3498篇 |
1971年 | 2627篇 |
1968年 | 2578篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
G.J. Hager 《Applied Surface Science》2006,252(19):6558-6561
Utilizing Au4004+ primary ions produces large molecular ion yields, some in excess of unity, with minimal surface damage. A surprising observation is the occurrence of Au-analyte adducts as part of the ejecta desorbed by a single Au-cluster impact. We present data that demonstrate that Au and Au-adducts as secondary ions (e.g., AuCN−, AuGly− and AuCsI−) are the result of the interaction between a single primary ion, Au4004+ and the target atoms. 相似文献
872.
The dry etching characteristics of transparent and conductive indium-zinc oxide (IZO) films have been investigated using an inductively coupled high-density plasma. While the Cl2-based plasma mixture showed little enhancement over physical sputtering in a pure argon atmosphere, the CH4/H2/Ar chemistry produced an increase of the IZO etch rate. On the other hand, the surface morphology of IZO films after etching in Ar and Ar/Cl2 discharges is smooth, whereas that after etching in CH4/H2/Ar presents particle-like features resulting from the preferential desorption of In- and O-containing products. Etching in CH4/H2/Ar also produces formation of a Zn-rich surface layer, whose thickness (∼40 nm) is well-above the expected range of incident ions in the material (∼1 nm). Such alteration of the IZO layer after etching in CH4/H2/Ar plasmas is expected to have a significant impact on the transparent electrode properties in optoelectronic device fabrication. 相似文献
873.
874.
M. Mayr K. -H. Speidel M. Knopp W. Karle T. Faestermann F. Hagelberg H. -J. Simonis P. N. Tandon J. Gerber 《Zeitschrift für Physik A Hadrons and Nuclei》1987,327(2):157-161
[Theg-factor ratio of the first excited 3? and 5? states in40Ca was measured to beg 3/g 5=1.01(10) employing the implantation perturbed angular correlation technique. The static hyperfine fields (SF) in Fe and Gd hosts were used. In addition the lifetime of the 5? state was measured to be τ=426(7)ps. The values of the SF in Gd and Fe hosts were deduced and compared with systematics in this element region. 相似文献
875.
876.
877.
878.
The authors give a consistent affirmative response to a question of Juhász, Soukup and Szentmiklóssy: If GCH fails, there are (many) extraresolvable, not maximally resolvable Tychonoff spaces. They show also in ZFC that for ω<λ?κ, no maximal λ-independent family of λ-partitions of κ is ω-resolvable. In topological language, that theorem translates to this: A dense, ω-resolvable subset of a space of the form (DI(λ)) is λ-resolvable. 相似文献
879.
M. Bello-Hernandez G. Lopez-Lagomasino J. Minguez-Ceniceros 《Constructive Approximation》2007,26(3):339-359
We study linear and nonlinear simultaneous Fourier-Pade approximation for Angelesco systems of functions and give the exact
rate of convergence/divergence of the approximants in terms of the solution of associated vector equilibrium potential
problems which differ for the linear and nonlinear cases. 相似文献
880.
We consider queuing systems where customers are not allowed to queue, instead of that they make repeated attempts, or retrials, in order to enter service after some time. We obtain the distribution of the number of retrials produced by a tagged customer, until he finds an available server. 相似文献