全文获取类型
收费全文 | 815篇 |
免费 | 24篇 |
国内免费 | 7篇 |
专业分类
化学 | 519篇 |
晶体学 | 9篇 |
力学 | 22篇 |
数学 | 31篇 |
物理学 | 265篇 |
出版年
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 16篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 33篇 |
2012年 | 28篇 |
2011年 | 37篇 |
2010年 | 23篇 |
2009年 | 14篇 |
2008年 | 32篇 |
2007年 | 40篇 |
2006年 | 26篇 |
2005年 | 39篇 |
2004年 | 46篇 |
2003年 | 18篇 |
2002年 | 23篇 |
2001年 | 15篇 |
2000年 | 51篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 16篇 |
1994年 | 20篇 |
1993年 | 15篇 |
1992年 | 16篇 |
1991年 | 22篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1978年 | 16篇 |
1977年 | 7篇 |
1976年 | 17篇 |
1975年 | 15篇 |
1974年 | 12篇 |
1973年 | 5篇 |
1923年 | 4篇 |
排序方式: 共有846条查询结果,搜索用时 31 毫秒
81.
L. W. Andrews H. Morawitz E. Rupp H. Bauer W. F. Schirmer Karin Thaulow H. Lescoeur E. Biilman F. Lehmann J. Knox P. W. Robertson H. Wastenson G. S. Jamieson F. Utz L. Garnier F. Reinthaler J. A. Muller A. Kolb A. Feldhofen G. Adanti B. Oddo L. Vignon H. R. Procter und R. A. Seymour-Jones 《Fresenius' Journal of Analytical Chemistry》1923,62(10):401-407
Ohne Zusammenfassung 相似文献
82.
C. Barentin P. Muller C. Ybert J.-F. Joanny J.-M. di Meglio 《The European physical journal. E, Soft matter》2000,2(2):153-159
The surface shear viscosity of monolayers formed at the surface of water by adsorbed polyethyl- eneoxyde and by stearic acid
is measured as a function of the surface pressure of the monolayer using a new surface viscometer. The principle of the viscometer
is the measurement of the drag force on a circular disk undergoing a uniform translation at the water surface: a hydrodynamic
model based on the lubrication approximation allows a calculation of the surface viscosities from the absolute measurement
of the drag forces.
Received: 26 August 1999 相似文献
83.
84.
85.
A purely elastic transition in Taylor-Couette flow 总被引:1,自引:0,他引:1
Experimental evidence of a non-inertial, cellular instability in the Taylor-Couette flow of a viscoelastic fluid is presented. A linear stability analysis for an Oldroyd-B fluid, which is successful in describing many features of the experimental fluid, predicts the critical Deborah number,De
c
, at which the instability is observed. The dependence ofDe
c
on the value of the dimensionless gap between the cylinders is also determined.This paper is dedicated to Professor Hanswalter Giesekus on the occasion of his retirement as Editor of Rheologica Acta. 相似文献
86.
Freehand 3D ultrasound is increasingly being introduced in the clinic for diagnostics and image-assisted interventions. Various algorithms exist for combining 2D images of regular ultrasound probes to 3D volumes, being either voxel-, pixel- or function-based. Previously, the most commonly used input to 3D ultrasound reconstruction has been digitized analog video. However, recent scanners that offer access to digital image frames exist, either as processed or unprocessed data. To our knowledge, no comparison has been performed to determine which data source gives the best reconstruction quality. In the present study we compared both reconstruction algorithms and data sources using novel comparison methods for detecting potential differences in image quality of the reconstructed volumes. The ultrasound scanner used in this study was the Sonix RP from Ultrasonix Medical Corp (Richmond, Canada), a scanner that allow third party access to unprocessed and processed digital data. The ultrasound probe used was the L14-5/38 linear probe. The assessment is based on a number of image criteria: detectability of wire targets, spatial resolution, detectability of small barely visible structures, subjective tissue image quality, and volume geometry. In addition we have also performed the more “traditional” comparison of reconstructed volumes by removing a percentage of the input data. By using these evaluation methods and data from the specific scanner, the results showed that the processed video performed better than the digital scan-line data, digital video being better than analog video. Furthermore, the results showed that the choice of video source was more important than the choice of tested reconstruction algorithms. 相似文献
87.
88.
89.
J. A. Muller C. Reinhardt C. Fischbach A. Siebenschub V. Stanek N. M. Randall K. Bogoluboff H. Wdowiszewski F. Garrat D. J. Demorest J. R. Cain H. E. Walters F. C. T. Daniels A. J. Field A. Terni P. Malaguti B. S. Evans L. W. Winkler O. L. Barnebey G. L. Kelley J. A. Wiley E. Little J. Costa M. Gröger H. O. Ward P. Slawik W. Hild und F. Simion 《Fresenius' Journal of Analytical Chemistry》1923,63(9):348-359
Ohne Zusammenfassung 相似文献
90.
Hole-doped rare-earth manganite La0.7Ca0.3MnO3 and the electron-doped manganite La0.7Ce0.3MnO3 both show a metal-insulator transition around 250 K associated with a ferromagnetic transition and colossal magnetoresistance.
In an earlier publication we have reported the rectifying characteristic of La0.7Ca0.3MnO3/SrTiO3/La0.7Ce0.3MnO3 tunnel junction at room temperature, showing that it is possible to fabricate a diode out of the polaronic insulator regime
of doped manganites. Here we report the magneto-transport properties of such a tunnel junction above and below the metal-insulator
transition. We show, from the large positive magnetoresistance of the tunnel junction at low temperature, that La0.7Ce0.3MnO3 could be a minority spin carrier ferromagnet. The implication of this observation is discussed. 相似文献