全文获取类型
收费全文 | 3594篇 |
免费 | 122篇 |
国内免费 | 2篇 |
专业分类
化学 | 2362篇 |
晶体学 | 39篇 |
力学 | 73篇 |
数学 | 263篇 |
物理学 | 981篇 |
出版年
2023年 | 36篇 |
2022年 | 56篇 |
2021年 | 60篇 |
2020年 | 89篇 |
2019年 | 103篇 |
2018年 | 70篇 |
2017年 | 58篇 |
2016年 | 126篇 |
2015年 | 74篇 |
2014年 | 123篇 |
2013年 | 237篇 |
2012年 | 232篇 |
2011年 | 288篇 |
2010年 | 174篇 |
2009年 | 146篇 |
2008年 | 214篇 |
2007年 | 181篇 |
2006年 | 161篇 |
2005年 | 140篇 |
2004年 | 110篇 |
2003年 | 75篇 |
2002年 | 83篇 |
2001年 | 62篇 |
2000年 | 58篇 |
1999年 | 53篇 |
1998年 | 30篇 |
1997年 | 23篇 |
1996年 | 38篇 |
1995年 | 29篇 |
1994年 | 35篇 |
1993年 | 43篇 |
1992年 | 29篇 |
1991年 | 27篇 |
1989年 | 19篇 |
1988年 | 21篇 |
1987年 | 27篇 |
1986年 | 21篇 |
1985年 | 19篇 |
1984年 | 31篇 |
1983年 | 20篇 |
1982年 | 22篇 |
1981年 | 30篇 |
1980年 | 19篇 |
1979年 | 27篇 |
1978年 | 16篇 |
1977年 | 18篇 |
1976年 | 16篇 |
1975年 | 15篇 |
1973年 | 11篇 |
1957年 | 13篇 |
排序方式: 共有3718条查询结果,搜索用时 46 毫秒
981.
982.
Mohan Sikka Laura N. Cerini Surya S. Ghosh Karen I. Winey 《Journal of Polymer Science.Polymer Physics》1996,34(8):1443-1449
We have studied the melt intercalation of polystyrene into organically modified sodium bentonite, a layered, mica-type silicate, using a variety of techniques. Wide-angle X-ray scattering experiments on polymer/silicate hybrid samples demonstrate that intercalation of polymer chains leads to an ∼25% increase in the spacing between silicate layers. The magnitude of this increase, compared with the radius of gyration of the melt polymer, implies a flattened conformation of chains in the galleries. Low voltage scanning electron microscopy reveals voids in the intercalated hybrid matrix that correspond to regions where pristine polymer was present in the physical mixture of polymer and silicate before intercalation. Differential scanning calorimetry shows that only unintercalated polymer contributes to the measured glass transition trace, so that the magnitude of the trace is diminished upon intercalation. © 1996 John Wiley & Sons, Inc. 相似文献
983.
Transport in Porous Media - In this paper, an approximate integral equation solution for a horizontal, unsteady flow of two viscous incompressible fluids is derived. Wettability variation of the... 相似文献
984.
985.
986.
987.
Dipak Ghosh Argha Deb Md. Azizar Rahman Abdul Kayum Jafry Jayita Ghosh 《The European Physical Journal A - Hadrons and Nuclei》2000,8(1):97-101
An analysis of 16O-AgBr interaction data at 60A GeV in terms of factorial correlators is presented. The correlated moments are found to increase
with decreasing bin-bin separation D, following a power law within the region D
1. The data are also consistent with the dimension-independent scaling relation proposed by Seixas.
Received: 5 October 1998 / Accepted: 20 April 2000 相似文献
988.
Kevin C. Seavey Indrajit Ghosh Richard M. Davis Wolfgang G. Glasser 《Cellulose (London, England)》2001,8(2):149-159
Thermoplastic fiber composites were prepared using high modulus lyocell (regenerated cellulose) fibers for reinforcement and cellulose acetate butyrate (CAB) as matrix. Choices were made with regard to fiber options (fabric versus continuous tow) and method of matrix deposition (prepregging by powder coating, film stacking, or solution impregnating). The results suggest that solution-prepregged fiber tow consolidated at circa 200°C produced unidirectional consolidated panels with tensile strength, modulus, and strain at failure values of approximately 250MPa,>20GPa and 3–4%, respectively, at fiber volume contents of approximately 60%. Modulus and ultimate tensile strength increased with fiber content, and modulus followed rule-of-mixture behavior. Adequate surface wetting and matrix-fiber adhesion were found with solution-prepregged composites. The unexpectedly low strain at failure (2 to <4%) was attributed to brittle matrix failure, and failure surfaces revealed that the fibers, for the most part, remained intact after the matrix had failed. 相似文献
989.
990.
Shyamal Kumar Chattopadhyay Mosarraf Hossain Saktiprosad Ghosh Arur Kumar Guha 《Transition Metal Chemistry》1990,15(6):473-477
Summary The chelating behaviour of two biologically active ligands, pyridine-2-carboxaldehyde(4-phenyl) thiosemicarbazone(L1H) and pyridine-2-carboxaldehyde thiosemicarbazone(LH), towards FeIII, CoIII, FeII and RhIII has been investigated. The ligands act as tridentate N–N–S donors, resulting in the formation of bis-chelate complexes of the type MIII(A)2X·nH2O (A=L1 or L; X=Cl, ClO4; M=CoIII, RhIII, FeIII), FeII(L1H)2SO4·2H2O and FeII(L1)2·H2O. Biological activity of the ligands and the metal complexes in the form ofin vitro antibacterial activities towardsE. coli has been evaluated and the possible reasons for enhancement of the activity of ligands on coordination to metal ion is discussed. 相似文献