全文获取类型
收费全文 | 151篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
大气科学 | 14篇 |
地球物理 | 23篇 |
地质学 | 60篇 |
海洋学 | 22篇 |
天文学 | 29篇 |
综合类 | 1篇 |
自然地理 | 4篇 |
出版年
2016年 | 3篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 10篇 |
2001年 | 5篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1974年 | 8篇 |
1973年 | 2篇 |
1946年 | 1篇 |
1945年 | 1篇 |
1939年 | 1篇 |
1936年 | 1篇 |
1934年 | 2篇 |
1933年 | 1篇 |
1932年 | 1篇 |
1929年 | 1篇 |
1928年 | 1篇 |
1926年 | 1篇 |
1924年 | 1篇 |
1923年 | 2篇 |
1912年 | 1篇 |
1872年 | 1篇 |
排序方式: 共有153条查询结果,搜索用时 15 毫秒
51.
52.
The technique of instrumental neutron activation analysis (INAA) has been used to analyze chip samples of geological material for 12 elements. Discriminant analysis has been used to classify the unknown chip samples to the correct stratum in a sedimentary succession. 相似文献
53.
W. Saunders W. J. Sutherland S. J. Maddox O. Keeble S. J. Oliver M. Rowan-Robinson R. G. McMahon G. P. Efstathiou H. Tadros S. D. M. White C. S. Frenk A. Carramiñana M. R. S. Hawkins 《Monthly notices of the Royal Astronomical Society》2000,317(1):55-64
We present the catalogue, mask, redshift data and selection function for the PSC z survey of 15 411 IRAS galaxies across 84 per cent of the sky. Most of the IRAS data are taken from the Point Source Catalog, but this has been supplemented and corrected in various ways to improve the completeness and uniformity. We quantify the known imperfections in the catalogue, and we assess the overall uniformity, completeness and data quality. We find that overall the catalogue is complete and uniform to within a few per cent at high latitudes and 10 per cent at low latitudes. Ancillary information, access details, guidelines and caveats for using the catalogue are given. 相似文献
54.
Jin Ba Noel S. Keenlyside Wonsun Park Mojib Latif Ed Hawkins Hui Ding 《Climate Dynamics》2013,41(7-8):2133-2144
Atlantic Multidecadal Variability (AMV) is investigated in a millennial control simulation with the Kiel Climate Model (KCM), a coupled atmosphere–ocean–sea ice model. An oscillatory mode with approximately 60 years period and characteristics similar to observations is identified with the aid of three-dimensional temperature and salinity joint empirical orthogonal function analysis. The mode explains 30 % of variability on centennial and shorter timescales in the upper 2,000 m of the North Atlantic. It is associated with changes in the Atlantic Meridional Overturning Circulation (AMOC) of ±1–2 Sv and Atlantic Sea Surface Temperature (SST) of ±0.2 °C. AMV in KCM results from an out-of-phase interaction between horizontal and vertical ocean circulation, coupled through Irminger Sea convection. Wintertime convection in this region is mainly controlled by salinity anomalies transported by the Subpolar Gyre (SPG). Increased (decreased) dense water formation in this region leads to a stronger (weaker) AMOC after 15 years, and this in turn leads to a weaker (stronger) SPG after another 15 years. The key role of salinity variations in the subpolar North Atlantic for AMV is confirmed in a 1,000 year long simulation with salinity restored to model climatology: No low frequency variations in convection are simulated, and the 60 year mode of variability is absent. 相似文献
55.
56.
L.J. Lanzerotti T.P. Armstrong C.G. Maclennan G.M. Simnett A.F. Cheng R.E. Gold D.J. Thomson S.M. Krimigis K.A. Anderson S.E. Hawkins III M. Pick E.C. Roelof E.T. Sarris S.J. Tappin 《Planetary and Space Science》1993,41(11-12)
This paper presents an overview of a number of the principal findings regarding the hot plasmas (E 50 keV) in Jupiter's magnetosphere by the HISCALE instrument during the encounter of the Ulysses spacecraft with the planet in February 1992. The hot plasma ion fluxes measured by HI-SCALE in the dayside magnetosphere are similar to those measured in the same energy range in this region by the Voyager spacecraft in 1979. Within the dayside plasma sheet, the hot-ion energy densities are comparable with, or larger than, the magnetic field energy densities; these hot ions are found to corotate at about one-half the planetary corotational speed. For ions of energies 500 keV/nucleon, the protons contributed from 50–60% to as much as 80% of the energy content of these plasmas. Strong, magnetic-field-aligned streaming was found for both the ions and electrons in the high-latitude duskside magnetosphere. The ion and electron pitch-angle distributions could be characterized by cos25 α throughout many of the high anisotropy intervals of the outbound pass. There is some evidence in the ion pitch-angle distributions for a corotational component in the hot plasmas at high Jovian latitudes. While there are limitations owing to the finite geometries of the detector telescope systems on the determination of the angular spreads of the ion and electron beams, the measurements show that there are intervals when the particle distributions are not bidirectional. At such times, locally the hot plasmas could be carrying currents of 10−4μAm−2. The temporal variations in the streaming electron fluxes are substantially larger than the variations measured for the fluxes that are more locally mirroring. The temporal variations contain periodicities that may correspond to hydromagnetic wave frequencies in the magnetosphere as well as to larger scale motions of magnetospheric plasmas. On nearly half of the days for about a 130 day interval around the time of the Ulysses encounter with the planet, particles of Jovian origin were measured in the interplanetary medium. An event discussed herein shows evidence of an energy dependence of the particle release process from the planetary magnetosphere into the interplanetary medium. 相似文献
57.
Douglas M. Hawkins 《Mathematical Geology》1984,16(4):393-406
The borehole slotting method previously proposed by Gordon and Reyment for two boreholes may be extended to three or more boreholes, but soon becomes computationally intractable. We propose another method based on the mixture model of cluster analysis, the computational labor of which increases linearly with the number of boreholes. This method produces profiles of the unknown strata to which the individual boreholes are easily matched by the two-borehole slotting method. 相似文献
58.
The 2dF Galaxy Redshift Survey: the dependence of galaxy clustering on luminosity and spectral type 总被引:1,自引:0,他引:1
Peder Norberg Carlton M. Baugh Ed Hawkins Steve Maddox Darren Madgwick Ofer Lahav Shaun Cole Carlos S. Frenk Ivan Baldry Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole Jackson Ian Lewis Stuart Lumsden John A. Peacock Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,332(4):827-838
We investigate the dependence of galaxy clustering on luminosity and spectral type using the 2dF Galaxy Redshift Survey (2dFGRS). Spectral types are assigned using the principal-component analysis of Madgwick et al. We divide the sample into two broad spectral classes: galaxies with strong emission lines ('late types') and more quiescent galaxies ('early types'). We measure the clustering in real space, free from any distortion of the clustering pattern owing to peculiar velocities, for a series of volume-limited samples. The projected correlation functions of both spectral types are well described by a power law for transverse separations in the range 2<( σ / h -1 Mpc)<15 , with a marginally steeper slope for early types than late types. Both early and late types have approximately the same dependence of clustering strength on luminosity, with the clustering amplitude increasing by a factor of ∼2.5 between L * and 4 L *. At all luminosities, however, the correlation function amplitude for the early types is ∼50 per cent higher than that of the late types. These results support the view that luminosity, and not type, is the dominant factor in determining how the clustering strength of the whole galaxy population varies with luminosity. 相似文献
59.
E. Hawkins S. Maddox E. Branchini W. Saunders 《Monthly notices of the Royal Astronomical Society》2001,325(2):589-598
We measure the autocorrelation function, ξ , of galaxies in the IRAS Point Source Catalogue galaxy redshift (PSC z ) survey and investigate its dependence on the far-infrared colour and absolute luminosity of the galaxies. We find that the PSC z survey correlation function can be modelled out to a scale of 10 h −1 Mpc as a power law of slope 1.30±0.04 and correlation length 4.77±0.20 . At a scale of 75 h −1 Mpc we find the value of J 3 to be 1500±400 .
We also find that galaxies with higher 100 μm/60 μm flux ratio, corresponding to cooler dust temperatures, are more strongly clustered than warmer galaxies. Splitting the survey into three colour subsamples, we find that, between 1 and 10 h−1 Mpc, the ratio of ξ is a factor of 1.5 higher for the cooler galaxies compared with the hotter galaxies. This is consistent with the suggestion that hotter galaxies have higher star formation rates, and correspond to later-type galaxies which are less clustered than earlier types.
Using volume-limited subsamples, we find a weak variation of ξ as a function of absolute luminosity, in the sense that more luminous galaxies are less clustered than fainter galaxies. The trend is consistent with the colour dependence of ξ and the observed colour–luminosity correlation, but the large uncertainties mean that it has a low statistical significance. 相似文献
We also find that galaxies with higher 100 μm/60 μm flux ratio, corresponding to cooler dust temperatures, are more strongly clustered than warmer galaxies. Splitting the survey into three colour subsamples, we find that, between 1 and 10 h
Using volume-limited subsamples, we find a weak variation of ξ as a function of absolute luminosity, in the sense that more luminous galaxies are less clustered than fainter galaxies. The trend is consistent with the colour dependence of ξ and the observed colour–luminosity correlation, but the large uncertainties mean that it has a low statistical significance. 相似文献
60.
Roberto De Propris Matthew Colless John A. Peacock Warrick J. Couch Simon P. Driver Michael L. Balogh Ivan K. Baldry Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Chris Collins Nicholas Cross Gavin Dalton George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Edward Hawkins Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick Peder Norberg Will Percival Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,351(1):125-132