全文获取类型
收费全文 | 1254篇 |
免费 | 19篇 |
国内免费 | 7篇 |
专业分类
化学 | 726篇 |
晶体学 | 4篇 |
力学 | 30篇 |
数学 | 218篇 |
物理学 | 302篇 |
出版年
2021年 | 11篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2016年 | 16篇 |
2015年 | 12篇 |
2014年 | 16篇 |
2013年 | 58篇 |
2012年 | 42篇 |
2011年 | 62篇 |
2010年 | 20篇 |
2009年 | 24篇 |
2008年 | 49篇 |
2007年 | 46篇 |
2006年 | 62篇 |
2005年 | 60篇 |
2004年 | 39篇 |
2003年 | 62篇 |
2002年 | 37篇 |
2001年 | 31篇 |
2000年 | 17篇 |
1999年 | 13篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 23篇 |
1995年 | 21篇 |
1994年 | 18篇 |
1993年 | 18篇 |
1992年 | 21篇 |
1991年 | 14篇 |
1990年 | 17篇 |
1989年 | 17篇 |
1988年 | 21篇 |
1987年 | 14篇 |
1986年 | 21篇 |
1985年 | 29篇 |
1984年 | 24篇 |
1983年 | 12篇 |
1982年 | 14篇 |
1981年 | 17篇 |
1980年 | 13篇 |
1979年 | 20篇 |
1978年 | 19篇 |
1977年 | 19篇 |
1976年 | 27篇 |
1975年 | 25篇 |
1974年 | 21篇 |
1973年 | 17篇 |
1970年 | 10篇 |
1968年 | 9篇 |
1966年 | 7篇 |
排序方式: 共有1280条查询结果,搜索用时 15 毫秒
111.
112.
P C Bell 《The Journal of the Operational Research Society》2008,59(3):313-321
Short selling and replaning have emerged from different sources as tools to enhance revenues. This paper presents these tools in the context of revenue management, and highlights their similarities and differences. Conditions under which the use of short selling and replanning enhance revenues are derived, and the impact of these tools on overbooking limits is investigated. 相似文献
113.
L E Humes D D Dirks T S Bell G E Kincaid 《The Journal of the Acoustical Society of America》1987,81(3):765-773
In the present study, speech-recognition performance was measured in four hearing-impaired subjects and twelve normal hearers. The normal hearers were divided into four groups of three subjects each. Speech-recognition testing for the normal hearers was accomplished in a background of spectrally shaped noise in which the noise was shaped to produce masked thresholds identical to the quiet thresholds of one of the hearing-impaired subjects. The question addressed in this study is whether normal hearers with a hearing loss simulated through a shaped masking noise demonstrate speech-recognition difficulties similar to those of listeners with actual hearing impairment. Regarding overall percent-correct scores, the results indicated that two of the four hearing-impaired subjects performed better than their corresponding subgroup of noise-masked normal hearers, whereas the other two impaired listeners performed like the noise-masked normal listeners. A gross analysis of the types of errors made suggested that subjects with actual and simulated losses frequently made different types of errors. 相似文献
114.
Shan She Weimin Xuan Nicola L. Bell Robert Pow Eduard Garrido Ribo Zoe Sinclair De-Liang Long Leroy Cronin 《Chemical science》2021,12(7):2427
The precise control over the formation of complex nanostructures, e.g. polyoxometalates (POMs), at the sub-nanoscale is challenging but critical if non-covalent architectures are to be designed. Combining biologically-evolved systems with inorganic nanostructures could lead to sequence-mediated assembly. Herein, we exploit oligopeptides as multidentate structure-directing ligands via metal-coordination and hydrogen bonded interactions to modulate the self-assembly of POM superstructures. Six oligopeptides (GH, AH, SH, G2H, G4H and G5H) are incorporated into the cavities of Molybdenum Blue (MB) POM nanowheels. It is found that the helicity of the nanowheel can be readily switched (Δ to Λ) by simply altering the N-terminal amino acid on the peptide chain rather than their overall stereochemistry. We also reveal a delicate balance between the Mo-coordination and the hydrogen bonds found within the internal cavity of the inorganic nanowheels which results in the sequence mediated formation of two unprecedented asymmetrical nanowheel frameworks: {Mo122Ce5} and {Mo126Ce4}.Peptide sequence can be used to control the self-assembly and structures of nanoscale molybdenum blue polyoxometalate (POM) wheel-shaped clusters. 相似文献
115.
Ohne Zusammenfassung 相似文献
116.
I. Bang J. A. Mandel H. Steudel O. Folin L. Pincussen F. Fregl F. Emich H. Lieb J. V. Dubsky A. Fodor J. Herzog W. Denis R. D. Bell L. Hannaert R. Wodon C. Vallée A. Polonowski P. E. Howe E. L. Kennaway K. L. Gad-Andresen R. Fosse M. Nicloux und G. Welter 《Fresenius' Journal of Analytical Chemistry》1923,63(1-2):72-80
Ohne Zusammenfassung 相似文献
117.
Ch. A. Bell und F. L. Teed 《Fresenius' Journal of Analytical Chemistry》1882,21(1):127-129
Ohne Zusammenfassung 相似文献
118.
119.
120.