全文获取类型
收费全文 | 1405篇 |
免费 | 20篇 |
国内免费 | 7篇 |
专业分类
化学 | 721篇 |
晶体学 | 13篇 |
力学 | 45篇 |
数学 | 294篇 |
物理学 | 359篇 |
出版年
2021年 | 10篇 |
2020年 | 11篇 |
2019年 | 9篇 |
2017年 | 11篇 |
2016年 | 26篇 |
2015年 | 17篇 |
2014年 | 17篇 |
2013年 | 69篇 |
2012年 | 58篇 |
2011年 | 72篇 |
2010年 | 36篇 |
2009年 | 35篇 |
2008年 | 53篇 |
2007年 | 64篇 |
2006年 | 65篇 |
2005年 | 55篇 |
2004年 | 62篇 |
2003年 | 31篇 |
2002年 | 34篇 |
2001年 | 29篇 |
2000年 | 23篇 |
1999年 | 22篇 |
1998年 | 20篇 |
1997年 | 19篇 |
1996年 | 29篇 |
1995年 | 19篇 |
1994年 | 35篇 |
1993年 | 31篇 |
1992年 | 19篇 |
1991年 | 25篇 |
1990年 | 33篇 |
1989年 | 19篇 |
1988年 | 28篇 |
1987年 | 17篇 |
1986年 | 19篇 |
1985年 | 32篇 |
1984年 | 25篇 |
1983年 | 14篇 |
1982年 | 20篇 |
1981年 | 25篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 16篇 |
1977年 | 10篇 |
1976年 | 19篇 |
1975年 | 9篇 |
1974年 | 17篇 |
1973年 | 14篇 |
1972年 | 9篇 |
1969年 | 8篇 |
排序方式: 共有1432条查询结果,搜索用时 15 毫秒
1.
2.
A current interpretation of XPS spectra of Ni metal assumes that the main 6 eV satellite is due to a two hole c3d94s2 (c is a core hole) final state effect. We report REELS observation in AES at low voltages of losses (plasmons and inter-band transitions) corresponding to the satellite structures in Ni metal 2p spectra. The satellite near 6 eV is attributed to a predominant surface plasmon loss. A current interpretation of Ni 2p spectra of oxides and other compounds is based on charge transfer assignments of the main peak at 854.6 eV and the broad satellite centred at around 861 eV to the cd9L and the unscreened cd8 final-state configurations, respectively (L is a ligand hole). Multiplet splittings have been shown to be necessary for assignment of Fe 2p and Cr 2p spectral profiles and chemical states. The assignments of Ni 2p states are re-examined with intra-atomic multiplet envelopes applied to Ni(OH)2, NiOOH and NiO spectra. It is shown that the free ion multiplet envelopes for Ni2+ and Ni3+ simulate the main line and satellite structures for Ni(OH)2 and NiOOH. Fitting the NiO Ni 2p spectral profile is not as straightforward as the hydroxide and oxyhydroxide. It may involve contributions from inter-atomic, non-local electronic coupling and screening effects with multiplet structures significantly different from the free ions as found for MnO. A scheme for fitting these spectra using multiplet envelopes is proposed. 相似文献
3.
A vacuum-deposited aluminium layer (20 nm) is sandwiched between two layers of laminated oriented polypropylene (OPP) film whose thickness varies from 20 to 40 μm. Selected areas of this sealed system were transparentised by the redistribution of the aluminium layer without breaking the seal or causing damage to the OPP film using a 75 W Q-switched Nd:YAG laser. The resultant transparentised films contain aluminium particles, distorted polymer areas and intact areas of the vacuum-coated aluminium layer. This paper investigates the effect of microscopic features upon the overall transmissivity of the laser-treated films and hence the quality of the transparentisation process. 相似文献
4.
5.
Casey Chun Zhou Eric J. Stoner Kent D. Stewart L. Steven Hollis Edmund D. Matayoshi Gregory M. Brill 《Tetrahedron》2004,60(47):10611-10618
Oritavancin is a semi-synthetic glycopeptide antibiotic which is structurally related to vancomycin. When oritavancin bisphosphate is dried in vacuo with heat, a new compound forms. This new compound is stable only in the solid state and reverts to oritavancin in solution. Highly enriched samples of this compound were obtained by preparative HPLC and the structure of this compound was elucidated by using one and two-dimensional (1H and 13C) NMR spectroscopy in conjunction with computer-assisted molecular modeling. It has been determined that oritavancin adopts a conformation similar to that of vancomycin in solution, while the new compound is the unnatural R-AB-biaryl atropisomer of oritavancin. This is the first observation and isolation of an AB-biaryl atropisomer in an intact member of the vancomycin family of glycopeptide antibiotics. 相似文献
6.
7.
Stewart C Zieminski A Blessing S Crittenden R Draper P Dzierba A Heinz R Krider J Marshall T Martin J Sambamurti A Smith P Sulanke T Gomez R Dauwe L Haggerty H Malamud E Nikolic M Hagopian S Abrams R Ares J Goldberg H Halliwell C Margulies S McLeod D Salminen A Solomon J Wu G Ellsworth R Goodman J Gupta S Yodh G Watts T Abramov V Antipov Y Baldin B Denisov S Glebov V Gorin Y Kryshkin V Petrukhin A Polovnikov S Sulyaev R 《Physical review D: Particles and fields》1990,42(5):1385-1395
8.
A global existence theorem for the general coagulation–fragmentation equation with unbounded kernels
In this article an existence theorem is proved for the coagulation–fragmentation equation with unbounded kernel rates. Solutions are shown to be in the space X+ = {c∈L1: ∫ (1 + x)∣c(x)∣dx < ∞} whenever the kernels satisfy certain growth properties and the non-negative initial data belong to X+. The proof is based on weak L1 compactness methods applied to suitably chosen approximating equations. 相似文献
9.
10.