全文获取类型
收费全文 | 404870篇 |
免费 | 4383篇 |
国内免费 | 1396篇 |
专业分类
化学 | 212528篇 |
晶体学 | 6345篇 |
力学 | 17703篇 |
综合类 | 7篇 |
数学 | 47197篇 |
物理学 | 126869篇 |
出版年
2021年 | 2943篇 |
2020年 | 3264篇 |
2019年 | 3755篇 |
2018年 | 4746篇 |
2017年 | 4631篇 |
2016年 | 7003篇 |
2015年 | 4496篇 |
2014年 | 6905篇 |
2013年 | 18612篇 |
2012年 | 13901篇 |
2011年 | 17018篇 |
2010年 | 11502篇 |
2009年 | 11316篇 |
2008年 | 15273篇 |
2007年 | 15501篇 |
2006年 | 14524篇 |
2005年 | 13217篇 |
2004年 | 12106篇 |
2003年 | 10719篇 |
2002年 | 10492篇 |
2001年 | 12056篇 |
2000年 | 9177篇 |
1999年 | 7193篇 |
1998年 | 5906篇 |
1997年 | 5986篇 |
1996年 | 5517篇 |
1995年 | 5146篇 |
1994年 | 4904篇 |
1993年 | 4852篇 |
1992年 | 5356篇 |
1991年 | 5390篇 |
1990年 | 5141篇 |
1989年 | 4978篇 |
1988年 | 5048篇 |
1987年 | 4948篇 |
1986年 | 4732篇 |
1985年 | 6283篇 |
1984年 | 6635篇 |
1983年 | 5477篇 |
1982年 | 5895篇 |
1981年 | 5773篇 |
1980年 | 5587篇 |
1979年 | 5657篇 |
1978年 | 5978篇 |
1977年 | 5801篇 |
1976年 | 6056篇 |
1975年 | 5510篇 |
1974年 | 5588篇 |
1973年 | 5928篇 |
1972年 | 3756篇 |
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
971.
R. A. Kotel’nikova G. N. Bogdanov G. V. Zotina V. S. Romanova Z. N. Parnes 《Physics of the Solid State》2002,44(3):576-577
Efficient quenching of eosin phosphorescence by amino-acid derivatives of fullerene (AADFs) such as C60-alanine and C60-glycine in aqueous solutions indicates the possibility of transferring electrons from eosin to fullerene upon collisions or in the exciplex state. To investigate electron transfer in the protein structure, we studied the process of incorporation of C60-alanine and C60-glycine into the heme pocket of myoglobin by controlling Förster quenching. The dissociation constant for the protein-AADF complex was estimated. 相似文献
972.
973.
P. Paasche T. Valenzuela D. Biswas C. Angelescu G. Werth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):295-300
We have examined experimentally the motional spectrum of an electron cloud confined in a Penning trap. When the axial oscillation
is excited by a radio frequency field the resonance exhibits a double structure. Both components depend differently on the
number of trapped electrons and have different shape and width. We conclude that one of them corresponds to the excitation
of the individual electrons while the other is the center-of-mass mode of the cloud. The threshold behaviour of the center-of-mass
resonance suggests that it is a parametric instability of a Mathieu type equation of motion.
Received 11 July 2001 and Received in final form 12 November 2001 相似文献
974.
This note discusses the need to use various data-compaction schemes in the implementation of sophisticated large-scale linear programming codes on modest personal computers. It demonstrates a method whereby the overhead of using these schemes is significantly reduced on Intel 80 x 86 processors. 相似文献
975.
The optimal return function for a Borel measurable gambling problem with a bounded utility function was shown by Strauch (1967)
to be universally measurable when the problem is leavable in the sense that the gambler may terminate play at any time. The
same is shown here for the more general class of nonleavable problems.
Research supported by National Science Foundation Grant DMS-8801085. 相似文献
976.
Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg - 相似文献
977.
978.
979.
980.
W. Hufenbach R. Böhm A. Langkamp L. Kroll T. Ritschel 《Mechanics of Composite Materials》2006,42(2):151-162
The basic damage and failure models of multiaxially reinforced composites with a thermoplastic matrix are presented and verified.
Within the framework of continuum damage mechanics, a phenomenological model is introduced, where the damage is defined as
a change in the elasticity tensor. For damage identification, a specific ultrasonic device was developed. A combination of
an immersion set-up and a contact coupling device formed a system for an efficient determination of stiffness-tensor components
from convenient sets of velocity measurements. Linked to a tensile machine, it allowed us to measure the anisotropic damage
of the new materials group caused by tensile loading.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 42, No. 2, pp. 221–234, March–April, 2006. 相似文献