全文获取类型
收费全文 | 543篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
化学 | 324篇 |
晶体学 | 3篇 |
力学 | 11篇 |
数学 | 50篇 |
物理学 | 166篇 |
出版年
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 9篇 |
2013年 | 20篇 |
2012年 | 26篇 |
2011年 | 31篇 |
2010年 | 22篇 |
2009年 | 20篇 |
2008年 | 42篇 |
2007年 | 44篇 |
2006年 | 35篇 |
2005年 | 28篇 |
2004年 | 27篇 |
2003年 | 21篇 |
2002年 | 24篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 5篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1993年 | 10篇 |
1992年 | 14篇 |
1991年 | 8篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1986年 | 3篇 |
1984年 | 4篇 |
1982年 | 2篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1962年 | 1篇 |
1938年 | 1篇 |
1928年 | 1篇 |
1925年 | 1篇 |
1917年 | 2篇 |
1895年 | 2篇 |
排序方式: 共有554条查询结果,搜索用时 0 毫秒
551.
Jan Nordström Sofia Eriksson Peter Eliasson 《Journal of computational physics》2012,231(14):4867-4884
We study the influence of different implementations of no-slip solid wall boundary conditions on the convergence to steady-state of the Navier–Stokes equations. The various approaches are investigated using the energy method and an eigenvalue analysis. It is shown that the weak implementation is superior and enhances the convergence to steady-state for coarse meshes. It is also demonstrated that all the stable approaches produce the same convergence rate as the mesh size goes to zero. The numerical results obtained by using a fully nonlinear finite volume solver support the theoretical findings from the linear analysis. 相似文献
552.
Prance JR Shi Z Simmons CB Savage DE Lagally MG Schreiber LR Vandersypen LM Friesen M Joynt R Coppersmith SN Eriksson MA 《Physical review letters》2012,108(4):046808
We investigate the lifetime of two-electron spin states in a few-electron Si/SiGe double dot. At the transition between the (1,1) and (0,2) charge occupations, Pauli spin blockade provides a readout mechanism for the spin state. We use the statistics of repeated single-shot measurements to extract the lifetimes of multiple states simultaneously. When the magnetic field is zero, we find that all three triplet states have equal lifetimes, as expected, and this time is ~10 ms. When the field is nonzero, the T(0) lifetime is unchanged, whereas the T- lifetime increases monotonically with the field, reaching 3 sec at 1 T. 相似文献
553.
Abbasi A Risberg ED Eriksson L Mink J Persson I Sandström M Sidorov YV Skripkin MY Ullström AS 《Inorganic chemistry》2007,46(19):7731-7741
The octakis(DMSO) (DMSO = dimethylsulfoxide) neodymium(III), samarium(III), gadolinium(III), dysprosium(III), erbium(III), and lutetium(III) iodides crystallize in the monoclinic space group P21/n (No. 14) with Z = 4, while the octakis(DMSO) iodides of the larger lanthanum(III), cerium(III), and praseodymium(III) ions crystallize in the orthorhombic space group Pbca (No. 61), Z = 8. In all [Ln(OS(Me2)8]I3 compounds the lanthanoid(III) ions coordinate eight DMSO oxygen atoms in a distorted square antiprism. Up to three of the DMSO ligands were found to be disordered and were described by two alternative configurations related by a twist around the metal-oxygen (Ln-O) bond. To resolve the atomic positions and achieve reliable Ln-O bond distances, complete semirigid DMSO molecules with restrained geometry and partial occupancy were refined for the alternative sites. This disorder model was also applied on previously collected data for the monoclinic octakis(DMSO)yttrium(III) iodide. At ambient temperature, the eight Ln-O bond distances are distributed over a range of about 0.1 A. The average value increases from Ln-O 2.30, 2.34, 2.34, 2.36, 2.38, 2.40 to 2.43 A (Ln = Lu, Er, Y, Dy, Gd, Sm, and Nd) for the monoclinic [Ln(OSMe2)8]I3 structures, and from 2.44, 2.47 to 2.49 A (Ln = Pr, Ce, and La) for the orthorhombic structures, respectively. The average of the La-O and Nd-O bond distances remained unchanged at 100 K, 2.49 and 2.43 A, respectively. Despite longer bond distances and larger Ln-O-S angles, the cell volumes are smaller for the orthorhombic structures (Ln = Pr, Ce, and La) than for the monoclinic structure with Ln = Nd, showing a more efficient packing arrangement. Raman and IR absorption spectra for the [Ln(OS(CH3)2)8]I3 (Ln = La, Ce, Pr, Nd, Gd, Tb, Dy, Er, Lu, and Y) compounds, also deuterated for La and Y, have been recorded and analyzed by means of normal coordinate methods. The force constants for the Ln-O and S-O stretching modes in the complexes increase with decreasing Ln-O bond distance and show increasing polarization of the bonds for the smaller and heavier lanthanoid(III) ions. 相似文献
554.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献