全文获取类型
收费全文 | 1222篇 |
免费 | 29篇 |
国内免费 | 3篇 |
专业分类
化学 | 835篇 |
晶体学 | 22篇 |
力学 | 14篇 |
数学 | 100篇 |
物理学 | 283篇 |
出版年
2022年 | 10篇 |
2021年 | 23篇 |
2020年 | 36篇 |
2019年 | 22篇 |
2018年 | 14篇 |
2017年 | 9篇 |
2016年 | 20篇 |
2015年 | 18篇 |
2014年 | 12篇 |
2013年 | 62篇 |
2012年 | 52篇 |
2011年 | 68篇 |
2010年 | 40篇 |
2009年 | 26篇 |
2008年 | 64篇 |
2007年 | 59篇 |
2006年 | 73篇 |
2005年 | 63篇 |
2004年 | 50篇 |
2003年 | 47篇 |
2002年 | 43篇 |
2001年 | 30篇 |
2000年 | 22篇 |
1999年 | 16篇 |
1998年 | 13篇 |
1997年 | 20篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 16篇 |
1993年 | 8篇 |
1992年 | 17篇 |
1990年 | 9篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 13篇 |
1986年 | 9篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 22篇 |
1982年 | 19篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1974年 | 9篇 |
1972年 | 4篇 |
1968年 | 5篇 |
排序方式: 共有1254条查询结果,搜索用时 15 毫秒
101.
S. N. Liddick P. F. Mantica R. V.F. Janssens B. A. Brown M. P. Carpenter A. D. Davies M. Honma M. Horoi T. Mizusaki A. C. Morton W. F. Mueller T. Otsuka J. Pavan H. Schatz A. Stolz S. L. Tabor B. E. Tomlin M. Wiedeking 《The European physical journal. Special topics》2007,150(1):135-136
We have utilized the selective process of β decay to
populate low-energy excited states in the neutron-rich 22Ti,
23V, 24Cr, and 25Mn nuclei. The goal was to systematically
track the monopole shift of the νf5/2 single-particle
level with increased occupancy of the πf7/2 orbital.
The β-decay properties of the parent nuclides, along
with the low-energy structure of the daughters, are
presented and compared with the results of shell model calculations
employing the GXPF1 interaction. 相似文献
102.
Alexander I. Nosich Elena I. Smotrova Svetlana V. Boriskina Trevor M. Benson Phillip Sewell 《Optical and Quantum Electronics》2007,39(15):1253-1272
Research into microdisk lasers demonstrates new achievements both in the technology and in the associated physical effects
and applications. Melting and rounding of the disk edge boosts the Q-factors due to improved surface smoothness. In-plane
cavity shape is widely used as a design instrument. Optimal shaping of pumped area lowers the threshold power. Photonic molecules
made of several microdisks as “photonic atoms” show lasing at several closely spaced frequencies. A microdisk with a single
quantum dot as an active region is considered as the most promising system for realisation of a single photon emitter necessary
for quantum computing. These new effects and devices can be simulated with accurate numerical techniques, developed recently
for “warm-cavity” linear modelling, that are able to bring a new vision of the physics of lasing. 相似文献
103.
The recent interest in human dynamics has led researchers to investigate the processes that explain human behaviour within different contexts. Here we are concerned in modelling the human response to a deadline, and in particular we look at the process of conference registration with an early bird deadline. We provide empirical evidence from a six-year conference registration data set that the bi-logistic growth function, with the interpretation as registration with an early bird deadline, can be viewed as a social mechanism. 相似文献
104.
Ronald Millett Henry Schriemer Trevor Hall Karin Hinzer 《Optical and Quantum Electronics》2008,40(14-15):1239-1245
We demonstrate the results of an analysis of laterally coupled distributed feedback (LC-DFB) lasers with higher order gratings, including the effects of radiating partial waves. For a given fabrication resolution, first-order gratings, if they can be reliably manufactured, always provide the strongest coupling. However, at resolutions requiring higher order gratings, if duty cycles of >0.5 are used, the lowest grating order is not always the one with the strongest coupling. An analysis of the rounding of the grating teeth showed that the required threshold gain was increased by nearly 20% when the rectangular grating was rounded in fabrication. 相似文献
105.
I. Brown R. N. Carpenter E. Link J. S. Mitchell 《Journal of Radioanalytical and Nuclear Chemistry》1986,107(6):337-351
Heavy radiohalogenated derivatives of methylene blue of potential value as possible diagnostic and endoradiotherapeutic agents for malignant melanoma, have been synthesized by both electrophilic and nucleophilic reaction routes. Thermal halogen isotope exchange in molten crown ether catalyst facilitated the rapid preparation of high specific activity radioiodinated and [211At]-astatinated derivatives; radiochemical yields were in the order of 60–79%. Radiohalogenation mediated by chloramine-T or via diazonium intermediary proved more laborious, far less efficient and inappropriately is only suited to the preparation of low specific activity product. 相似文献
106.
107.
108.
Pietro Bollinger Philip Cooper Hans U. Gubler Albert Leutwiler Trevor Payne 《Helvetica chimica acta》1990,73(5):1197-1204
Compound (Z)- 8a has been found to display interesting antiinflammatory activity. In order to prepare derivatives with a wide variety of substituents in the aromatic part of the molecule, a new synthesis of the key intermediates 9a-g was developed starting from thiophene-3-carboxylic acid ( 11 ) and substituted benzyl bromides. The conversion of 9a-g to 10a-g follows a known procedure. Ketones 10a-g , on reaction with alkyl (dialkoxy-phosphoryl)acetate, followed by isomer separation and alkaline ester hydrolysis, yielded the desired derivatives (Z)- 8a-g and (E)- 8a-g . The biologically most interesting compound (Z)- 8a is currently undergoing clinical trials. 相似文献
109.
K.A. Schmidt M. Bergström G.B. Hagemann B. Herskind G. Sletten P.G. Varmette J. Domscheit H. Hübel S.W. Ødegård S. Frattini A. Bracco B. Million M.P. Carpenter R.V.F. Janssens T.L. Khoo T. Lauritsen C.J. Lister S. Siem I. Wiedenhöver D.J. Hartley L.L. Riedinger A. Maj W.C. Ma R. Terry 《The European Physical Journal A - Hadrons and Nuclei》2001,12(1):15-28
High-spin properties of the nucleus 169Hf have been studied through the fusion evaporation reaction 96Zr(76Ge,3n)169Hf at a beam energy of 310 MeV. The known rotational bands have been extended considerably and 6 new bands have been established,
four of which form coupled bands with pronounced M1 connections. Quasiparticle assignments are suggested for the new band structures, and it appears that coupling to vibrational
degrees of freedom plays a role. Both coupled bands involve the excitation of quasiprotons. In the region of highest spin,
a large alignment gain is interpreted in terms of a mixed crossing where an h
9/2 and an h
11/2 quasiproton provide the two signatures of the aligning configuration.
Received: 23 March 2001 / Accepted: 20 September 2001 相似文献
110.