全文获取类型
收费全文 | 15943篇 |
免费 | 2473篇 |
国内免费 | 1711篇 |
专业分类
化学 | 11689篇 |
晶体学 | 196篇 |
力学 | 852篇 |
综合类 | 73篇 |
数学 | 1543篇 |
物理学 | 5774篇 |
出版年
2024年 | 60篇 |
2023年 | 323篇 |
2022年 | 566篇 |
2021年 | 586篇 |
2020年 | 639篇 |
2019年 | 647篇 |
2018年 | 581篇 |
2017年 | 513篇 |
2016年 | 743篇 |
2015年 | 777篇 |
2014年 | 983篇 |
2013年 | 1216篇 |
2012年 | 1404篇 |
2011年 | 1492篇 |
2010年 | 1064篇 |
2009年 | 910篇 |
2008年 | 1049篇 |
2007年 | 955篇 |
2006年 | 841篇 |
2005年 | 732篇 |
2004年 | 552篇 |
2003年 | 459篇 |
2002年 | 428篇 |
2001年 | 306篇 |
2000年 | 306篇 |
1999年 | 252篇 |
1998年 | 224篇 |
1997年 | 198篇 |
1996年 | 183篇 |
1995年 | 144篇 |
1994年 | 185篇 |
1993年 | 130篇 |
1992年 | 126篇 |
1991年 | 96篇 |
1990年 | 91篇 |
1989年 | 85篇 |
1988年 | 45篇 |
1987年 | 31篇 |
1986年 | 34篇 |
1985年 | 29篇 |
1984年 | 22篇 |
1983年 | 11篇 |
1982年 | 15篇 |
1981年 | 7篇 |
1980年 | 17篇 |
1979年 | 8篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
Song DY 《Physical review D: Particles and fields》1995,51(10):5790-5796
143.
Song DY 《Physical review D: Particles and fields》1994,49(12):6794-6798
144.
Kui Zhao Xiuqin Lu Yehao Cheng Qingli Li Min Li Zhichang Li Jiyu Guo Shuyuan Li Qinghua Zhang Xiaobin Song Chenglie Jiang 《Zeitschrift für Physik A Hadrons and Nuclei》1994,348(2):95-98
Angular distributions of elastic and inelastic scattering have been measured for152Sm+12C at 63.2 MeV and148Nd+16O at 90.9 MeV. An evident interference pattern in the inelastic scattering has been observed for the first time in a strong Coulomb coupling system.We are indebted to Dr. S. Pieper for supplying the Ptolemy Program. One of us (Chenglie Jiang) would like to acknowledge the Argonne National Laboratory for the opportunity given, to perform theoretical calculations with the code Ptolemy during his visit there. Thanks are also due to Mr. H. Folger (GSI, Germany) for supplying the targets. This work was supported in part by China National Nature Science Fundation. 相似文献
145.
146.
147.
148.
Summary In earlier works, the gauge theorem was proved for additive functionals of Brownian motion of the form
0
t
q(B
s
)ds, whereq is a function in the Kato class. Subsequently, the theorem was extended to additive functionals with Revuz measures in the Kato class. We prove that the gauge theorem holds for a large class of additive functionals of zero energy which are, in general, of unbounded variation. These additive functionals may not be semi-martingales, but correspond to a collection of distributions that belong to the Kato class in a suitable sense. Our gauge theorem generalizes the earlier versions of the gauge theorem.Research supported in part by NSA grant MDA-92-H-30324 相似文献
149.
Taking a typical local and industry-orientated applied chemistry major as an example with focusing on the major changes in the form and content of the petrochemical industry, the way to reform the core curriculum system and teaching contents is presented. Based on the changing tendency of refinement of the petrochemical industry, a complete curriculum system with distinctive industry characteristics is set up according to the principles of the emerging engineering education (3E) with several reasonable suggestions. A new model for the construction of a 3E major in chemistry-related majors is suggested. It is a good reference for the construction of curriculum systems for other local and industry-orientated colleges who want to make 3E reform. 相似文献
150.
This paper compares the kinetics of exchanges of phenylethanethiolate ligands (PhC2S-) of the monolayer-protected clusters (MPCs) Au(38)(SC2Ph)(24) and Au(140)(SC2Ph)(53) with p-substituted arylthiols (p-X-PhSH), where X = NO(2), Br, CH(3), OCH(3), and OH. First-order rate constants at 293 K for exchange of the first ca. 25% of the ligands on the molecule-like Au(38)(SC2Ph)(24) MPC, measured using (1)H NMR, vary linearly with the in-coming arythiol concentration; ligand exchange is an overall second-order reaction. Remarkably, the second-order rate constants for ligand exchange on Au(38)(SC2Ph)(24) are very close to those of corresponding exchange reactions on the larger nanoparticle Au(140)(SC2Ph)(53) MPCs. These are the first results that quantitatively show that the chemical reactivity of different sized nanocrystals is almost independent of size; presumably, this is because the locus of the initial ligand exchanges is a common kind of site, thought to be the nanocrystal vertexes. The rates of later stages of exchange (beyond ca. 25%) differ for Au(38) and Au(140) cores, the latter being much slower presumably due to its larger terrace-like surface atom content. The reverse exchange reaction was studied for Au(38)(p-X-arylthiolate)(24) MPCs (X = NO(2), Br, and CH(3)), where the in-coming ligand is now phenylethanethiol. Remarkably, the rate constants of both forward and reverse exchanges display identical substituent effects, which implies a concurrent bonding of both in-coming and leaving ligands to the Au core in the rate-determining step, as in an associative mechanism. X = NO(2) gives the fastest rates, and the ratio of forward and reverse rate constants gives an equilibrium constant of K(EQ,PE) = 4.0 that is independent of X. 相似文献