全文获取类型
收费全文 | 78246篇 |
免费 | 351篇 |
国内免费 | 374篇 |
专业分类
化学 | 24282篇 |
晶体学 | 789篇 |
力学 | 6749篇 |
数学 | 32048篇 |
物理学 | 15103篇 |
出版年
2022年 | 40篇 |
2021年 | 36篇 |
2018年 | 10448篇 |
2017年 | 10272篇 |
2016年 | 6076篇 |
2015年 | 854篇 |
2014年 | 317篇 |
2013年 | 363篇 |
2012年 | 3794篇 |
2011年 | 10514篇 |
2010年 | 5638篇 |
2009年 | 6055篇 |
2008年 | 6612篇 |
2007年 | 8752篇 |
2006年 | 222篇 |
2005年 | 1296篇 |
2004年 | 1527篇 |
2003年 | 1965篇 |
2002年 | 1005篇 |
2001年 | 247篇 |
2000年 | 294篇 |
1999年 | 156篇 |
1998年 | 195篇 |
1997年 | 149篇 |
1996年 | 196篇 |
1995年 | 115篇 |
1994年 | 75篇 |
1993年 | 95篇 |
1992年 | 53篇 |
1991年 | 63篇 |
1990年 | 49篇 |
1989年 | 58篇 |
1988年 | 58篇 |
1987年 | 59篇 |
1986年 | 57篇 |
1985年 | 47篇 |
1984年 | 43篇 |
1983年 | 36篇 |
1982年 | 41篇 |
1981年 | 40篇 |
1980年 | 47篇 |
1979年 | 46篇 |
1978年 | 34篇 |
1914年 | 45篇 |
1913年 | 40篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
1907年 | 32篇 |
1904年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
152.
153.
154.
155.
We prove that any 43-fold covering of the plane with translates of a triangle can be decomposed into two coverings. 相似文献
156.
157.
Wei Wang Li-Ping Pang Zun-Quan Xia 《应用数学学报(英文版)》2007,23(1):29-38
In this paper,the UV-theory and P-differential calculus are employed to study second-order ex-pansion of a class of D.C.functions and minimization problems.Under certain conditions,some properties ofthe U-Lagrangian,the second-order expansion of this class of functions along some trajectories are formulated.Some first and second order optimality conditions for the class of D.C.optimization problems are given. 相似文献
158.
The interactive two-state model of cell membrane ion channels in an electric field is formulated on the Bethe lattice by means
of the exact recursion relations. The probability of channel opening or maximum fractions of open potassium and sodium channels
are obtained by solving a non-linear algebraic equation. Using known parameters for the conventional mean-field theory the
model gives a good agreement with the experiment both at low and high trans-membrane potential values. For intermediate voltages,
the numerical results imply that collective effects are introduced by trans-membrane voltage. 相似文献
159.
Khaled A. Aamer Gregory N. Tew 《Journal of polymer science. Part A, Polymer chemistry》2007,45(6):1109-1121
Supramolecular block‐random copolymers containing [Ir(terpy)2]3+ in the side chain were synthesized via postfunctionalization of a P(S‐b‐ACterpy) block copolymer. Absorbance and emission spectra compared to a model compound show that the polymer backbone has a minor effect on the polymer absorbance but produces a larger shift for the phosphorescence signals to higher wavelength. Dynamic light scattering of the metal complex containing copolymer studied in various solvents showed monomodal aggregation with decreasing aggregate size as the solvent dielectric constant increased. The copolymer precursor P(S‐b‐ACterpy) shows multimodal aggregation in different solvents with the major population consisting of single chains. This difference in behavior between the two polymers is attributed to the electrolytic nature of the complex and the amphiphilicity induced by the charged metal complex. Supramolecular copolymers like these will continue to have interesting self‐organizational properties and may find applications in multicomponent systems for photoinduced charge separation processes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1109–1121, 2007 相似文献
160.
Roderich Tumulka 《Foundations of Physics》2007,37(2):186-197
In a recent paper Conway and Kochen, Found. Phys. 36, 2006, claim to have established that theories of the Ghirardi-Rimini-Weber
(RW) type, i.e., of spontaneous wave function collapse, cannot be made relativistic. On the other hand, relativistic GRW-type
theories have already been presented, in my recent paper, J. Stat. Phys. 125, 2006, and by Dowker and Henson, J. Stat. Phys.
115, 2004. Here, I elucidate why these are not excluded by the arguments of Conway and Kochen.
相似文献