全文获取类型
收费全文 | 6854篇 |
免费 | 157篇 |
国内免费 | 14篇 |
专业分类
化学 | 3960篇 |
晶体学 | 62篇 |
力学 | 224篇 |
数学 | 965篇 |
物理学 | 1814篇 |
出版年
2021年 | 53篇 |
2020年 | 67篇 |
2019年 | 64篇 |
2018年 | 49篇 |
2017年 | 44篇 |
2016年 | 127篇 |
2015年 | 129篇 |
2014年 | 111篇 |
2013年 | 243篇 |
2012年 | 279篇 |
2011年 | 330篇 |
2010年 | 206篇 |
2009年 | 166篇 |
2008年 | 307篇 |
2007年 | 276篇 |
2006年 | 301篇 |
2005年 | 266篇 |
2004年 | 240篇 |
2003年 | 194篇 |
2002年 | 196篇 |
2001年 | 168篇 |
2000年 | 146篇 |
1999年 | 99篇 |
1998年 | 98篇 |
1997年 | 80篇 |
1996年 | 107篇 |
1995年 | 111篇 |
1994年 | 115篇 |
1993年 | 119篇 |
1992年 | 129篇 |
1991年 | 109篇 |
1990年 | 101篇 |
1989年 | 69篇 |
1988年 | 94篇 |
1987年 | 76篇 |
1986年 | 82篇 |
1985年 | 88篇 |
1984年 | 85篇 |
1983年 | 86篇 |
1982年 | 80篇 |
1981年 | 73篇 |
1980年 | 72篇 |
1979年 | 76篇 |
1978年 | 72篇 |
1977年 | 76篇 |
1976年 | 76篇 |
1975年 | 57篇 |
1974年 | 64篇 |
1973年 | 63篇 |
1972年 | 39篇 |
排序方式: 共有7025条查询结果,搜索用时 31 毫秒
41.
42.
43.
44.
Rüdiger Schultz Leen Stougie Maarten H. van der Vlerk 《Mathematical Programming》1998,83(1-3):229-252
In this paper we present a framework for solving stochastic programs with complete integer recourse and discretely distributed right-hand side vector, using Gröbner basis methods from computational algebra to solve the numerous second-stage integer programs. Using structural properties of the expected integer recourse function, we prove that under mild conditions an optimal solution is contained in a finite set. Furthermore, we present a basic scheme to enumerate this set and suggest improvements to reduce the number of function evaluations needed. 相似文献
45.
R. Klein R. Grieser L. Hoog G. Huber I. Klaft P. Merz T. Kühl S. Schröder M. Grieser D. Habs W. Petrich D. Schwalm 《Zeitschrift für Physik A Hadrons and Nuclei》1992,342(4):455-461
We have performed for the first time precision spectroscopy on a coasting fast7Li+ ion beam in a storage ring. The ion beam moving with 6.4% speed of light was first electron cooled and then merged with two counterpropagating laser beams acting on two different hyperfine transitions sharing a common upper level (λ-system). One laser was frequency locked to thea 3 127J2 hfs frequency component established as a secondary frequency standard at 514 nm. The second laser was tuned over theλ-resonance, which was recorded relative to127J2 hfs components. This experiment is sensitive to the time dilation in fast moving frames and will lead to new limits for the verification of special relatively. The present status of the experiment and perspectives in accuracy are discussed. 相似文献
46.
47.
Hans Peters Hans van der Stel Ton Storcken 《Mathematical Methods of Operations Research》1993,38(2):213-229
A voting scheme assigns to each profile of alternatives reported byn individuals a compromise alternative. A voting scheme is strategy-proof if no individual is better off by lying, i.e., not reporting a best alternative. In this paper the main results concern the case where the set of alternatives is the Euclidean plane and the preferences are Euclidean. It is shown that for strategy-proof voting schemes continuity is equivalent to convexity of the range of the voting scheme. Using a result by Kim and Roush (1984), this leads to characterizations of surjective or unanimous, anonymous, strategy-proof voting schemes.Furthermore, the paper contains an extensive discussion of related results in the area. 相似文献
48.
49.
50.
E. W. N. Glover R. Kleiss J. J. van der Bij 《Zeitschrift fur Physik C Particles and Fields》1990,47(3):435-448
We calculate, the partial width for the tree level decay of theZ boson into four massive fermions atO(α2) and \(O(\alpha _s^2 )\) . Analytic expressions for the helicity amplitudes are presented. We also present ‘observable’ widths for the case when the fermions are energetic and well separated, and make a comparison between the massive and massless matrix elements in this region. We make a direct comparison between the four fermion decay and the production and decay of the Higgs boson via the Bjorken mechanism, \(Z \to H\mu ^ + \mu ^ - \to q\bar q\mu ^ + \mu ^ - \) . Provided the detector resolution is good, \(\Delta m_{q\bar q} \) ~ few GeV, the Higgs signal stands clearly above the four fermion background for all Higgs boson masses considered. 相似文献