全文获取类型
收费全文 | 56篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
大气科学 | 2篇 |
地球物理 | 9篇 |
地质学 | 19篇 |
海洋学 | 6篇 |
天文学 | 13篇 |
自然地理 | 10篇 |
出版年
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 2篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2011年 | 4篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有59条查询结果,搜索用时 218 毫秒
1.
A marine magnetic survey was conducted over the Dellwood Knolls area of the northeast Pacific in September 1977 using a proton precession magnetometer and Loran-C positioning. Geomagnetic field reference stations were located at Victoria and Port Hardy. In addition, a recently developed ocean bottom magnetometer was deployed in the survey area. The cross-over error, a measure of survey accuracy, and the factors contributing to it are discussed. In high magnetic gradient regions, the part of the error related to the uncertainty in ship position implies that the repeatability of the Loran-C navigation system is of the order of 30 metres. Part of the error is also due to time variations of the geomagnetic field. This latter effect can be significantly reduced by correcting to a well located reference station. Because of the areal distribution of the geomagnetic coast effect, a land station close to the survey area may not be as effective as a more distant site. Referencing to an ocean bottom magnetometer, at least to moderate levels of disturbance, is comparable to correcting to a well located land station. Using a combination of land and ocean bottom reference data produced a reduction in the cross-over error from 25 to 11 nT for this survey, effectively removing the geomagnetic variation term. This technique should prove even more useful for surveys conducted during periods of higher geomagnetic activity.Contribution from the Earth Physics Branch No. 824. 相似文献
2.
Shane M. Ohline Malcolm R. Reid Shamus L.G. Husheer Kim I. Currie Keith A. Hunter 《Marine Chemistry》2007
Accurate measurement of seawater pH has long been sought by marine chemists (for example: [Dickson, A.G. 1993a. The measurement of sea water pH. Marine Chemistry, 44, 131–142, Dickson, A.G. 1993b. pH buffers for sea water media based on the total hydrogen ion concentration scale. Deep-Sea Research, 40, 107–118; Zhang, 1996; Tapp, M., Hunter, K.A., Currie, K. and Macaskill, B. 2000. Apparatus of continuous-flow underway spectrophotometric measurement of surface water pH. Marine Chemistry 72(2–4), 193–202; Friis, K., Koetzinger, A., Wallace, D.W.R. 2004. Spectrophotometric pH measurement in the ocean: Requirements, design and testing of an autonomous charge-coupled device detector system. Limnology and Oceanography: Methods 2, 126–136]. Recently, such attempts have taken on greater significance as anthropogenic carbon dioxide emissions may create rapidly changing oceanic pH. Spectrophotometric techniques have been accepted generally as the best for determination of seawater pH. Here we report a new technique using thymol blue as the indicator dye and fitting the entire spectrum from 400 to 900 nm rather than measuring the absorbance values at only two or three points in the spectrum. This full-spectrum modelling enables a reduction in signal to noise over other techniques. In the laboratory, we find with seawater samples a pH precision increase of five-fold “within” a sample and seven-fold “between” samples when comparing the full spectrum to the three-point method of analysis [Zhang, H., Byrne, R.H. 1996. Spectrophotometric pH measurements of surface seawater at in-situ conditions: absorbance and protonation behaviour of thymol blue. Marine Chemistry 52, 17–25]. 相似文献
3.
4.
Robert G. Currie 《Astrophysics and Space Science》1973,20(2):509-518
Application of a new data adaptive approach to power spectrum estimation has yielded evidence for a double solar cycle line in the Zurich sunspot time history. There is significant power from 8 to 15 yr in the spectrum with the primary line at 11.1 yr and three attendant multiplets that may be significant. The first four harmonics of the solar cycle are detected too. Quite marginal evidence for a peak at 65 yr in the spectrum is presented. These results closely correspond to those recently found in the geomagnetic spectrum. 相似文献
5.
A. Currie 《Marine pollution bulletin》1974,5(8):118-119
Cromarty Firth on the north-east coast of Scotland is an area of international importance to wildfowl, and the whole area has been designated a ‘Site of Special Scientific Importance’ by the Nature Conservancy Council. There are proposals to establish National Nature Reserves in two bays in the Firth. The area has also become a centre of activity for the oil industry exploiting the North Sea oilfield. Repeated oil spillages are threatening the conservation value of the area and unless strong measures are taken to reduce and treat oil pollution from all sources, there could be enormous damage to wildlife. 相似文献
6.
Two anhydrous equilibria can be written among the components of stilpnomelane, chlorite, white mica and quartz, namely 89 daphnite+131 Fe-celadonite+190 quartz=96 stilpnomelane+71 muscovite, and amesite+Mg-celadonite=muscovite+clinochlore. We assume that the free energy change of reaction, ΔG=ΔGo+ΣRT lnaij, is approximated by ΔG=A?BT +C(P?1)+ΣRT lnaij, where ΔGo is the free energy change of the end-member components at temperature T and pressure P, ai is the activity of component i whose coefficient in the equilibrium is j, and A, B and C are constants to be determined. Values of C can be approximated by the change in volume on reaction, namely C=406.517 J/bar for the first reaction and C=0.613 J/bar for the second reaction. Constants A and B were determined by using six occurrences of the assemblage stilpnomelane–chlorite–white mica for which P–T have been otherwise estimated. Using solution models from the literature, linear regression gives for the first equation A=?6118.269 kJ, B=?4584.09 J/K, and for the second equation A=19.397 kJ, B=66.72 J/K. These values predict P–T within 0.5 kbar and 25 K for all occurrences, and appear reasonably robust relative to probable analytical errors. P–T are determined by intersection of the curves generated by given compositions in P–T space. Fine-grained and/or zoned chlorite and white mica make application of the geothermobarometer difficult in some instances, but our work in the Bathurst region of New Brunswick suggests that, with patience and care, useful analyses can be obtained, and the database for the geothermobarometer greatly expanded. 相似文献
7.
Simone Dell��Agnello Caterina Lops Giovanni O. Delle Monache Douglas G. Currie Manuele Martini Roberto Vittori Angioletta Coradini Cesare Dionisio Marco Garattini Alessandro Boni Claudio Cantone Riccardo March Giovanni Bellettini Roberto Tauraso Mauro Maiello Luca Porcelli Simone Berardi Nicola Intaglietta 《Experimental Astronomy》2011,32(1):19-35
MAGIA is a mission approved by the Italian Space Agency (ASI) for Phase A study. Using a single large-diameter laser retroreflector, a large laser retroreflector array and an atomic clock onboard MAGIA we propose to perform several fundamental physics and absolute positioning metrology experiments: VESPUCCI, an improved test of the gravitational redshift in the Earth?CMoon system predicted by General Relativity; MoonLIGHT-P, a precursor test of a second generation Lunar Laser Ranging (LLR) payload for precision gravity and lunar science measurements under development for NASA, ASI and robotic missions of the proposed International Lunar Network (ILN); Selenocenter (the center of mass of the Moon), the determination of the position of the Moon center of mass with respect to the International Terrestrial Reference Frame/System (ITRF/ITRS); this will be compared to the one from Apollo and Lunokhod retroreflectors on the surface; MapRef, the absolute referencing of MAGIA??s lunar altimetry, gravity and geochemical maps with respect to the ITRF/ITRS. The absolute positioning of MAGIA will be achieved thanks to: (1) the laboratory characterization of the retroreflector performance at INFN-LNF; (2) the precision tracking by the International Laser Ranging Service (ILRS), which gives two fundamental contributions to the ITRF/ITRS, i.e. the metrological definition of the geocenter (the Earth center of mass) and of the scale of length; (3) the radio science and accelerometer payloads; (4) support by the ASI Space Geodesy Center in Matera, Italy. Future ILN geodetic nodes equipped with MoonLIGHT and the Apollo/Lunokhod retroreflectors will become the first realization of the International Moon Reference Frame (IMRF), the lunar analog of the ITRF. 相似文献
8.
9.
10.