全文获取类型
收费全文 | 86篇 |
免费 | 2篇 |
专业分类
化学 | 23篇 |
力学 | 2篇 |
数学 | 9篇 |
物理学 | 54篇 |
出版年
2021年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 4篇 |
2010年 | 7篇 |
2009年 | 2篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1988年 | 4篇 |
1986年 | 1篇 |
1984年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有88条查询结果,搜索用时 31 毫秒
41.
42.
43.
44.
Research in the fields of filtration and dewatering connected with the use of ultrasound (US) has been carried out mainly with small laboratory-scale batch or continuously operating devices. So far the only large scale industrial cake filtration applications have been developed and manufactured by Larox Oyj for mining industry. These applications apply ultrasound for cleaning of ceramic capillary action elements having at maximum total filtration area of approximately 150 m2. Several hundreds of filter units have been delivered worldwide during the past two decades. 相似文献
45.
46.
Electronic Speckle Pattern Interferometry (ESPI) is a sensitive optical method commonly used for making full-field measurements of surface displacements. It would be very desirable to be able to extend the technique also to determine surface strains. This would provide a full-field, non-contact strain measurement method that avoids the substantial installation burden of strain gauges. A mathematical approach is described where the ESPI data from an in-plane interferometer are numerically differentiated to determine surface strains. This is a challenging process because numerical differentiation is very sensitive to the presence of noise and ESPI data are inherently noisy. In addition, the phase information from ESPI data are wrapped modulo-2π. The resulting phase discontinuities make it difficult to use local averaging to smooth the data. A technique is described here where phasors are used to avoid the need for phase unwrapping. The effect of noise is reduced by a localized multiple smoothing technique that is effective in preserving spatial resolution, even near very high strain concentrations. Example measurements are shown and the effectiveness of the proposed method is illustrated. 相似文献
47.
48.
Heikkinen S Permi P Kilpeläinen I 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2001,148(1):53-60
Two methods for the measurement of (2)J(NCalpha) and (1)J(NCalpha) in (15)N/(13)C-labeled small and medium-size proteins are described. The current approach is based on simplified (13)C(alpha)-coupled (15)N HSQC spectra, where the two (2)J(NCalpha) doublets are separated into two subspectra corresponding to the alpha and beta spin states of the residue's own alpha carbon. The displacement of the two (2)J(NCalpha) doublets between the two subspectra provides an accurate value for (1)J(NCalpha). The alpha/beta filtration is achieved by taking the sum and difference of the recorded complementary in-phase and antiphase J-coupled spectra. J-multiplication is utilized in one of the proposed methods. In this method, an additional coupling evolution period, which is incremented in concert with t(1), is included in the pulse sequence making it possible to scale the peak-to-peak separation. 相似文献
49.
50.
Diverting Hydrogenations with Wilkinson's Catalyst towards Highly Reactive Rhodium(I) Species 下载免费PDF全文
Dr. Jesus E. Perea‐Buceta Dr. Israel Fernández Dr. Sami Heikkinen Dr. Kirill Axenov Dr. Alistair W. T. King Teemu Niemi Dr. Martin Nieger Prof. Markku Leskelä Prof. Timo Repo 《Angewandte Chemie (International ed. in English)》2015,54(48):14321-14325
The addition of Barton's base has a dramatic effect on the classic rhodium(III)‐mediated hydrogenations promoted by Wilkinson′s catalyst. Following the initial oxidative addition, a barrierless reductive elimination of HCl from the traditional rhodium(III) intermediates instantly produces a rhodium(I) monohydride species, which is remarkably reactive in the hydrogenation of several internal alkynes and functionalized trisubstituted alkenes. The direct formation of this species is unprecedented upon addition of molecular hydrogen and its catalytic potential has been hitherto barely explored. 相似文献