全文获取类型
收费全文 | 13311篇 |
免费 | 3486篇 |
国内免费 | 1354篇 |
专业分类
化学 | 4239篇 |
晶体学 | 86篇 |
力学 | 188篇 |
综合类 | 97篇 |
数学 | 2038篇 |
物理学 | 11503篇 |
出版年
2024年 | 47篇 |
2023年 | 245篇 |
2022年 | 501篇 |
2021年 | 598篇 |
2020年 | 556篇 |
2019年 | 479篇 |
2018年 | 440篇 |
2017年 | 455篇 |
2016年 | 612篇 |
2015年 | 552篇 |
2014年 | 772篇 |
2013年 | 1119篇 |
2012年 | 787篇 |
2011年 | 927篇 |
2010年 | 744篇 |
2009年 | 798篇 |
2008年 | 1019篇 |
2007年 | 967篇 |
2006年 | 931篇 |
2005年 | 793篇 |
2004年 | 698篇 |
2003年 | 626篇 |
2002年 | 629篇 |
2001年 | 464篇 |
2000年 | 508篇 |
1999年 | 352篇 |
1998年 | 350篇 |
1997年 | 247篇 |
1996年 | 141篇 |
1995年 | 116篇 |
1994年 | 98篇 |
1993年 | 79篇 |
1992年 | 81篇 |
1991年 | 61篇 |
1990年 | 57篇 |
1989年 | 58篇 |
1988年 | 38篇 |
1987年 | 27篇 |
1986年 | 29篇 |
1985年 | 25篇 |
1984年 | 31篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 13篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1975年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
Using the path integral method we derive quantum wave function and quantum fluctuations of charge andcurrent in the mesoscopic RLC circuit. We find that the quantum fluctuation of charge decreases with time, oppositely,the quantum fluctuation of current increases with time monotonously. Therefore there is a squeezing effect in the circuit.If some more charge devices are used in the mesoscopic-damped circuit, the quantum noise can be reduced. We also findthat uncertainty relation of charge and current periodically varies with the period π/2 in the under-damped case. 相似文献
64.
66.
Jrg Winkelmann 《Mathematische Nachrichten》1997,186(1):285-302
We investigate under which conditions an algebraic group G defined over a locally compact field k admitr a subgroup Γ? G(k) which is dense in the Zariski topology, but discerte in the topology induced by the locally compact topology on k. For non—solvable groups we provide a complete answer. 相似文献
67.
Montgomery Multiplication in GF(2k) 总被引:8,自引:0,他引:8
We show that the multiplication operation c=a · b · r-1 in the field GF(2k can be implemented significantly faster in software than the standard multiplication, where r is a special fixed element of the field. This operation is the finite field analogue of the Montgomery multiplication for modular multiplication of integers. We give the bit-level and word-level algorithms for computing the product, perform a thorough performance analysis, and compare the algorithm to the standard multiplication algorithm in GF(2k. The Montgomery multiplication can be used to obtain fast software implementations of the discrete exponentiation operation, and is particularly suitable for cryptographic applications where k is large. 相似文献
68.
采用固源Si分子束外延,在较高的生长温度于Si(100)衬底上制备出Si1-xGex/Si量子阱发光材料。发光样品的质量和特性通过卢瑟福背散射、X射线双晶衍射及光致发光评估。背散射实验中观察到应变超晶格的反常沟道效应;X射线分析表明材料的生长是共度的、无应力释放的,结晶完整性好。低温光致发光主要是外延合金量子阱中带边激子的无声发射和横光学声子参与的激子复合。并讨论了生长温度对量于阱发光的影响。 相似文献
69.
Based on the effective-field theory with self-spin correlations and the differential operator technique,physical properties of the spin-2 system with biaxial crystal field on the simple cubic, body-centered cubic, as well as faced-centered lattice have been studied. The influences of the external longitudinal magnetic field on the magnetization,internal energy, specific heat, and susceptibility have been discussed in detail. The phenomenon that the magnetization in the ground state shows quantum effects produced by the biaxial transverse crystal field has been found. 相似文献
70.
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