全文获取类型
收费全文 | 205222篇 |
免费 | 2531篇 |
国内免费 | 522篇 |
专业分类
化学 | 107790篇 |
晶体学 | 3163篇 |
力学 | 7852篇 |
综合类 | 3篇 |
数学 | 25545篇 |
物理学 | 63922篇 |
出版年
2020年 | 1826篇 |
2019年 | 1825篇 |
2018年 | 2372篇 |
2017年 | 2429篇 |
2016年 | 4043篇 |
2015年 | 2625篇 |
2014年 | 3940篇 |
2013年 | 9517篇 |
2012年 | 7110篇 |
2011年 | 8570篇 |
2010年 | 5885篇 |
2009年 | 5747篇 |
2008年 | 8156篇 |
2007年 | 7998篇 |
2006年 | 7457篇 |
2005年 | 6747篇 |
2004年 | 6093篇 |
2003年 | 5409篇 |
2002年 | 5255篇 |
2001年 | 5850篇 |
2000年 | 4417篇 |
1999年 | 3361篇 |
1998年 | 2829篇 |
1997年 | 2752篇 |
1996年 | 2713篇 |
1995年 | 2516篇 |
1994年 | 2539篇 |
1993年 | 2510篇 |
1992年 | 2730篇 |
1991年 | 2554篇 |
1990年 | 2541篇 |
1989年 | 2432篇 |
1988年 | 2462篇 |
1987年 | 2444篇 |
1986年 | 2293篇 |
1985年 | 3059篇 |
1984年 | 3118篇 |
1983年 | 2737篇 |
1982年 | 2876篇 |
1981年 | 2709篇 |
1980年 | 2680篇 |
1979年 | 2776篇 |
1978年 | 2834篇 |
1977年 | 2743篇 |
1976年 | 2737篇 |
1975年 | 2661篇 |
1974年 | 2625篇 |
1973年 | 2818篇 |
1972年 | 1776篇 |
1971年 | 1487篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A. Hotzel P. Thirolf Ch. Ender D. Schwalm M. Mutterer P. Singer M. Klemens J. P. Theobald M. Hesse F. Gönnenwein H. v. d. Ploeg 《Zeitschrift für Physik A Hadrons and Nuclei》1987,356(3):299-308
The γ-ray spectrum of 252Cf(sf) was measured in the Darmstadt-Heidelberg Crystal Ball spectrometer, with a double ionization chamber mounted inside to detect the fission fragments. The measurement was aimed at a better understanding of an unusual component found in the high-energy region between 3 and 8 MeV, with fragment mass splits near symmetry. This component was proved to be predominantly emitted by the heavier fragment, to reach its highest intensity at a fragment mass split of 132:120, and to have an almost isotropic angular distribution. Calculations with the statistical code CASCADE could reproduce the main features. 相似文献
992.
S. B. Sakuta B. G. Novatsky D. N. Stepanov D. V. Aleksandrov Yu. A. Glukhov E. Yu. Nikol'sky 《Physics of Atomic Nuclei》2002,65(10):1771-1777
The (6Li, 7Be) and (6Li, 7Li) reactions on 6Li and 7Li nuclei were investigated in the angular interval 0°–20° in the laboratory system at a 6Li energy of 93 MeV. In addition to low-lying states of the 5,6He and 5,6Li nuclei, broad structures were observed near the t(3He)+d and t(3He)+t thresholds at the excitation energies of 16.75 (3/2+) and ~20 MeV (for 5He), 16.66 (3/2+) and ~20 MeV (5Li), 14.0 and 25 MeV (6He), and ~20 MeV (6Li). The angular distributions measured in the 7Li(6Li, 7Be)6He reaction for transitions to the ground state (0+) and excited states at E x=1.8 MeV (2+) and 14.0 MeV of the 6He nucleus were analyzed by the finite-range distorted-wave method assuming the 1p-and 1s-proton pickup mechanism. The (6Li, 7Be) and (6Li, 7Li) reactions were shown to proceed predominantly through the one-step pickup mechanism, and the broad structures observed at high excitation energies are considered as quasimolecular states of the t(3He)+d and t(3He)+t types. 相似文献
993.
H.O.U. Fynbo Y. Prezado J. Äystö U.C. Bergmann M.J.G. Borge P. Dendooven W. Huang J. Huikari H. Jeppesen P. Jones B. Jonson M. Meister G. Nyman M. Oinonen K. Riisager O. Tengblad I.S. Vogelius Y. Wang L. Weissman K.W. Rolander 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):135-138
994.
Bulanyi M. F. Gorban' A. A. Kovalenko A. V. Polezhaev B. A. Prokof'ev T. A. Khmelenko O. V. 《Russian Physics Journal》2002,45(12):1215-1219
The photoluminescence spectra of ZnS : Mn plastically deformed single crystals are investigated. It is established that the plastic strain causes the relative concentrations of individual manganese emission centers to change together with conditions of excitation of the centers whose nearest environment has been rearranged upon plastic strain. 相似文献
995.
We study a generalization of the analytic theory of first-order phase transitions to the cases of arbitrary droplet growth, of nonisothermal processes, and of heterogeneous centers in the system. We show that in all these cases, the spectra of droplet dimensions are similar. The same forms of the spectra are also obtained for the stationary condensation process in a spatially inhomogeneous system. 相似文献
996.
997.
998.
The open mapping and closed range theorems 总被引:1,自引:0,他引:1
999.
1000.
We develop an interactive approach for multiobjective decision-making problems, where the solution space is defined by a set of constraints. We first reduce the solution space by eliminating some undesirable regions. We generate solutions (partition ideals) that dominate portions of the efficient frontier and the decision maker (DM) compares these with feasible solutions. Whenever the decision maker prefers a feasible solution, we eliminate the region dominated by the partition ideal. We then employ an interactive search method on the reduced solution space to help the DM further converge toward a highly preferred solution. We demonstrate our approach and discuss some variations. 相似文献