全文获取类型
收费全文 | 399997篇 |
免费 | 3320篇 |
国内免费 | 1291篇 |
专业分类
化学 | 181969篇 |
晶体学 | 5481篇 |
力学 | 21652篇 |
综合类 | 2篇 |
数学 | 77007篇 |
物理学 | 118497篇 |
出版年
2020年 | 1873篇 |
2019年 | 2179篇 |
2018年 | 18919篇 |
2017年 | 19457篇 |
2016年 | 12532篇 |
2015年 | 4230篇 |
2014年 | 4437篇 |
2013年 | 11859篇 |
2012年 | 15220篇 |
2011年 | 29854篇 |
2010年 | 17780篇 |
2009年 | 18104篇 |
2008年 | 24273篇 |
2007年 | 29263篇 |
2006年 | 9074篇 |
2005年 | 15829篇 |
2004年 | 11840篇 |
2003年 | 11304篇 |
2002年 | 8519篇 |
2001年 | 7631篇 |
2000年 | 5955篇 |
1999年 | 4423篇 |
1998年 | 3795篇 |
1997年 | 3756篇 |
1996年 | 3640篇 |
1995年 | 3358篇 |
1994年 | 3119篇 |
1993年 | 3170篇 |
1992年 | 3431篇 |
1991年 | 3473篇 |
1990年 | 3282篇 |
1989年 | 3238篇 |
1988年 | 3307篇 |
1987年 | 3163篇 |
1986年 | 3062篇 |
1985年 | 4123篇 |
1984年 | 4308篇 |
1983年 | 3538篇 |
1982年 | 3898篇 |
1981年 | 3779篇 |
1980年 | 3668篇 |
1979年 | 3697篇 |
1978年 | 3936篇 |
1977年 | 3680篇 |
1976年 | 3901篇 |
1975年 | 3472篇 |
1974年 | 3579篇 |
1973年 | 3929篇 |
1972年 | 2385篇 |
1971年 | 1819篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
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
992.
V. I. Strunin A. A. Lyakhov G. Zh. Khudaibergenov V. V. Shkurkin 《Technical Physics》2002,47(6):760-766
A model of silane decomposition in a radio-frequency argon plasma is constructed. The concentrations of SiH4 decomposition products, as well as products of synthesis (higher silanes), are calculated. The role of metastable argon atoms in the formation of SiH3 radicals and the higher silanes is analyzed. 相似文献
993.
994.
Several variations of two-dimensional (workers x jobs) and three-dimensional (workers x jobs x machines) time- as well as cost-minimizing assignment problems, which arise owing to (i) precedence relations of some form among the jobs or (ii) capacity restrictions on workers/machines imposed by the requirement that the surplus resources have to be fully employed, have been considered in the literature. In this paper, an algorithm is presented for time-cost trade-off analysis which is applicable to any general pair of such constrained problems. The algorithm is also illustrated by a numerical example. 相似文献
995.
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
996.
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
997.
Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg - 相似文献
998.
999.
1000.
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