全文获取类型
收费全文 | 19866篇 |
免费 | 2127篇 |
国内免费 | 1221篇 |
专业分类
化学 | 7529篇 |
晶体学 | 184篇 |
力学 | 939篇 |
综合类 | 87篇 |
数学 | 5293篇 |
物理学 | 9182篇 |
出版年
2024年 | 22篇 |
2023年 | 217篇 |
2022年 | 244篇 |
2021年 | 446篇 |
2020年 | 577篇 |
2019年 | 533篇 |
2018年 | 557篇 |
2017年 | 687篇 |
2016年 | 688篇 |
2015年 | 597篇 |
2014年 | 985篇 |
2013年 | 2218篇 |
2012年 | 1338篇 |
2011年 | 1264篇 |
2010年 | 924篇 |
2009年 | 1351篇 |
2008年 | 1371篇 |
2007年 | 1309篇 |
2006年 | 1079篇 |
2005年 | 957篇 |
2004年 | 817篇 |
2003年 | 605篇 |
2002年 | 599篇 |
2001年 | 450篇 |
2000年 | 493篇 |
1999年 | 423篇 |
1998年 | 362篇 |
1997年 | 266篇 |
1996年 | 294篇 |
1995年 | 217篇 |
1994年 | 180篇 |
1993年 | 145篇 |
1992年 | 148篇 |
1991年 | 93篇 |
1990年 | 64篇 |
1989年 | 69篇 |
1988年 | 71篇 |
1987年 | 57篇 |
1986年 | 45篇 |
1985年 | 79篇 |
1984年 | 91篇 |
1983年 | 33篇 |
1982年 | 55篇 |
1981年 | 55篇 |
1980年 | 25篇 |
1979年 | 25篇 |
1978年 | 21篇 |
1977年 | 14篇 |
1976年 | 14篇 |
1973年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 843 毫秒
991.
Fourier transform surface enhanced Raman spectrometer is used to characterize Ω-mercaptoalkanols (HO(CH2)nSH, n=2, 6) chemisorption on silver surface from their aqueous solution of different pH values. 相似文献
992.
993.
A.W.Thomas 《中国物理C(英文版)》2010,34(9)
One of the most fascinating challenges facing modern strong interaction physics is to understand the origin of the spin of the nucleon in terms of the spin and orbital angular momentum of the quarks and gluons. We review recent progress on this problem as well as some of the uncertainties associated with state of the art lattice QCD simulations. In particular, we explain the importance of the corrections associated with chiral extrapolation and finite volume corrections, especially for the term B(0) extracted from the appropriate low moment of the deeply virtual Compton scattering amplitude. 相似文献
994.
Camille Thevenot Brice Vincent Sabu Thomas Didier Rouxel 《International Journal of Polymer Analysis and Characterization》2017,22(7):649-658
The purpose of this paper is to understand the mechanisms occurring during the ultrasonication of the copolymer poly(vinylidenedifluoride-trifluoroethylene). In these experimental conditions, the polymer adopts a core–shell structure and its hydrodynamic diameter is measured by dynamic light scattering. The results show that, without covalent bonds breakage, the hydrodynamic diameter decreases with ultrasonication time and a smaller size population appears. This evolution is reversible in a matter of days. A new two-step mechanism is proposed to describe this phenomenon: first the erosion of a core–shell structure and second the contraction of the core. Beyond shedding a new light on the phenomena occurring during the sonication of polymers used in nanocomposites elaboration, this work also strongly questions the traditional techniques used to study the degradation of polymers, which use the hydrodynamic diameter measurement to determine the molecular weight. 相似文献
995.
《应用有机金属化学》2017,31(12)
Chiral Jacobsen's catalysts grafted onto alkoxyl‐modified ZPS‐PVPA exhibit excellent activities (conv%, up to 96; sele%, up to 96; ee%, up to >99) in the asymmetric epoxidations of unfunctionalized olefins. The superior stabilities and the comfortable dispositions in large‐scale reactions contribute to the potential applications in industry. 相似文献
996.
Shahpoor Moradi 《理论物理通讯》2009,(7):30-32
For two particles with different spins, we derive the Bell's inequality. The inequality is investigated for two systems combining spin-1 and spin-1/; spin-1/2 and spin-3/2. We show that for these states Bell's inequality is violated. 相似文献
997.
J. V. Michalowicz J. M. Nichols F. Bucholtz C. C. Olson 《Journal of statistical physics》2009,136(1):89-102
This work derives a version of Isserlis’ theorem for the specific case of four mixed-Gaussian random variables. The theorem
is then used to derive an expression for the auto-bispectral density for quadratically nonlinear systems driven with mixed-Gaussian
iid noise.
C.C. Olson is a NRC Postdoctoral Research Associate. 相似文献
998.
999.
In many modern papers devoted to the calculation of radio emissions from extensive atmospheric showers (EASs) in the 10–100
MHz range, the radiation from EASs of charged particles moving with a velocity higher than the speed of light in air is identified
as Vavilov—Cherenkov radiation (VCR). In this paper it is shown that radio emissions from EASs at frequencies less than 100
MHz do not possess the properties of VCR recorded from EASs in the optical range.
Original Russian Text ? N.N. Kalmykov, A.A. Konstantinov, 2009, published in Vestnik Moskovskogo Universiteta. Fizika, 2009,
No. 3, pp. 99–102. 相似文献
1000.