全文获取类型
收费全文 | 72篇 |
免费 | 5篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 2篇 |
地球物理 | 10篇 |
地质学 | 24篇 |
海洋学 | 8篇 |
天文学 | 23篇 |
自然地理 | 9篇 |
出版年
2023年 | 1篇 |
2020年 | 7篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1986年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有77条查询结果,搜索用时 281 毫秒
1.
M. Cristina Fossi Silvia Casini Letizia Marsili Stefania Ancora Gabriele Mori Giovanni Neri Antonella Ausili Teresa Romeo Alessandra Moscatelli Giuseppe Notarbartolo Di Sciara 《Marine Ecology》2002,23(S1):184-189
Abstract. Endocrine Disrupting Chemicals (EDCs) have the potential to alter hormone pathways that regulate reproductive processes in wildlife and fisheries. In this research the unexplored hypothesis that Mediterranean top predator species (such as large pelagic fish and marine mammals) are potentially at risk due to EDCs is investigated. In the Mediterranean environment, top predators accumulate high concentrations of polyhalogenated aromatic hydrocarbons (PHAHs) and toxic metals, incurring high toxicological risk. Here we illustrate the need to develop sensitive biomarkers for evaluation of toxicological risk in top marine predators (Xiphias gladius, Thunnus thynnus thynnus) and non-lethal techniques, such as non-destructive biomarkers, for the hazard assessment of threatened species exposed to EDCs, such as marine mammals ( Stenella coeruleoalba, Tursiops truncatus, Delphinus delphis and Balaenoptera physalus ). 相似文献
2.
The South China Sea continental margin in the Qiongdongnan Basin (QDNB) area has incrementally prograded since 10.5 Ma generating a margin sediment prism more than 4km-thick and 150–200 km wide above the well-dated T40 stratigraphic surface. Core and well log data, as well as clinoform morphology and growth patterns along 28 2D seismic reflection lines, illustrate the evolving architecture and margin morphology; through five main seismic-stratigraphic surfaces (T40, T30, T27, T20 and T0) frame 15 clinothems in the southwest that reduce over some 200 km to 8 clinoforms in the northeast. The overall margin geometry shows a remarkable change from sigmoidal, strongly progradational and aggradational in the west to weakly progradational in the east. Vertical sediment accumulation rate increased significantly across the entire margin after 2.4 Ma, with a marked increase in mud content in the succession. Furthermore, an estimate of sediment flux across successive clinoforms on each of the three selected seismic cross sections indicate an overall decrease in sediment discharge west to east, away from the Red River depocenter, as well as a decrease in the percentage of total discharge crossing the shelf break in this same direction. The QDNB Late Cenozoic continental margin growth, with its overall increased sediment flux, responded to the climate-induced, gradual cooling and falling global sea level during this icehouse period. 相似文献
3.
Lacustrine basins and their deposits are good paleoclimate recorders and contain rich energy resources. Shelf-margin clinoforms do exist in deep lacustrine basins, but with striking differences from those in deep marine basins, caused by a correlation between the river-derived sediment supply and the lake level. This study uses empirical relationships to calculate the water and sediment discharge from rivers and coeval lake level during wet–dry cycles at 10 s of ky time scale. Sediment supply and lake-level changes are used for a stratigraphic forward model to understand how lacustrine clinoforms develop under different climate conditions. The results show that both wet and dry cycles can be associated with thick deep-water fan deposits, supporting the existing climate-driven lacustrine model proposed based on field data (e.g. Neogene Pannonian Basin and Eocene Uinta Basin). The wet period with high sediment supply and rising lake level creates the highly aggradational shelf, progradational slope and thick bottomset deposits. This is contrary from marine basin settings where the presence of rising shelf-margin trajectory commonly indicates limited deep-water fan deposits. This work suggests marine-based stratigraphic models cannot be directly applied to lacustrine basins. 相似文献
4.
Simon J. Meldrum Romeo S. Aquino Rene I. Gonzales Robert J. Burke Artha Suyadi Bambang Irianto Donald S. Clarke 《Journal of Geochemical Exploration》1994,50(1-3)
The Batu Hijau porphyry Cu---Au deposit lies in southwest Sumbawa Island, Indonesia. It is a world-class porphyry Cu deposit in an island are setting, and is typical of this deposit type in most features, including igneous association, morphology, hydrothermal alteration and mineralisation style.The region was not previously recognised as a porphyry Cu province; disseminated Cu sulphides were first recognised in float samples in southwest Sumbawa in 1987. Associated stream sediment sampling identified a broad area of anomalous Au and Cu in an area of greater than 5 km2 around Batu Hijau, including 169 ppb Au in BLEG samples and 580 ppm Cu in stream silts 1 km from the deposit. Mineralisation in bedrock at surface contains > 0.1 wt % Cu and > 0.1 ppm Au over an area of 0.6 km × 1.2 km, including a zone 300 m × 900 m containing > 0.3 wt % Cu. Areas with elevated Mo (> 30 ppm) form a distinctive annulus around this Cu-rich zone.Batu Hijau mineralisation is hosted in a tonalite intrusive complex, and diorite and metavolcanic wallrocks. There are no post-mineralisation igneous intrusions or breccia pipes within the deposit. The main tonalite intrusion forms a stock in the centre of the deposit, where it generally displays intensely pervasive potassic (biotite with magnetite-quartz) alteration and hosts most of the higher grade mineralisation. Younger tonalite dykes intruding the centre of this stock are generally less altered and mineralised than the older tonalite.The core zone of potassic alteration grades outward into extensive propylitic alteration (chlorite-epidote), with both variably overprinted by widespread fracture controlled intermediate argillic alteration (sericite-chlorite), and minor phyllic (sericite-pyrite) and sodic (albite) alteration. Argillic (sericite-kaolinite) and advanced argillic (kaolinite-alunite-pyrophyllite) assemblages occur near surface.Copper and Au grades within the orebody show a positive correlation with quartz stockwork intensity, although disseminated Cu sulphides are also common. Chalcopyrite and bornite are the principle hypogenal minerals, with minor chalcocite. Oxidation extends to a depth of 5 m to 85 m below surface across the deposit, and is underlain by weak supergene mineralisation. Drill testing of the deposit down to 650 m below surface reveals a single cylindrical to conical orebody of 334 million tonnes grading 0.8 wt % Cu and 0.69 gm per tonne Au; the depth extent of mineralisation is unknown. 相似文献
5.
Sokrat Amataj Todor Anovski Ralf Benischke Romeo Eftimi Laurence L. Gourcy Liliana Kola Ioannis Leontiadis Eftim Micevski Alqiviadis Stamos Jovan Zoto 《Environmental Geology》2007,51(5):749-753
Prespa Lake and Ohrid Lake constitute a hydraulic system shared between Albania, FYR of Macedonia and Greece. Karst rocks
separate both lakes. The elevation of Prespa Lake is about 150 m higher than that of Ohrid Lake. Considering these facts,
Cvijić formulated in 1906 the hypothesis that Prespa Lake recharges the St. Naum and Tushemisht springs at Ohrid lakeside.
Environmental isotopes demonstrated that Prespa Lake recharges about 37–42 and 52–54% of water emerging in St. Naum, and Tushemisht
springs, respectively. An artificial tracer experiment carried out in 2002 physically demonstrated the underground connection
between both lakes. This experiment confirmed the supposed underground connection and brought important information about
the groundwater velocity, transit time, and karst water conduits development. 相似文献
6.
Harald Geiger Ian Barnes Karl H. Becker Birger Bohn Theo Brauers Birgit Donner Hans-Peter Dorn Manfred Elend Carlos M. Freitas Dinis Dirk Grossmann Heinz Hass Holger Hein Axel Hoffmann Lars Hoppe Frank Hülsemann Dieter Kley Björn Klotz Hans G. Libuda Tobias Maurer Djuro Mihelcic Geert K. Moortgat Romeo Olariu Peter Neeb Dirk Poppe Lars Ruppert Claudia G. Sauer Oleg Shestakov Holger Somnitz William R. Stockwell Lars P. Thüner Andreas Wahner Peter Wiesen Friedhelm Zabel Reinhard Zellner Cornelius Zetzsch 《Journal of Atmospheric Chemistry》2002,42(1):323-357
Within the German Tropospheric Research Programme (TFS) numerous kinetic and mechanistic studies on the tropospheric reaction/degradation of the following reactants were carried out: oxygenated VOC, aromatic VOC, biogenic VOC, short-lived intermediates, such as alkoxy and alkylperoxy radicals.At the conception of the projects these selected groups were classes of VOC or intermediates for which the atmospheric oxidation mechanisms were either poorly characterised or totally unknown. The motivation for these studies was the attainment of significant improvements in our understanding of the atmospheric chemical oxidation processes of these compounds, particularly with respect to their involvement in photooxidant formation in the troposphere. In the present paper the types of experimental investigations performed and the results obtained within the various projects are briefly summarised. The major achievements are highlighted and discussed in terms of their contribution to improving our understanding of the chemical processes controlling photosmog formation in the troposphere. 相似文献
7.
Melchiorri A Ade PA de Bernardis P Bock JJ Borrill J Boscaleri A Crill BP De Troia G Farese P Ferreira PG Ganga K de Gasperis G Giacometti M Hristov VV Jaffe AH Lange AE Masi S Mauskopf PD Miglio L Netterfield CB Pascale E Piacentini F Romeo G Ruhl JE Vittorio N 《The Astrophysical journal》2000,536(2):L63-L66
We use the angular power spectrum of the cosmic microwave background, measured during the North American test flight of the Boomerang experiment, to constrain the geometry of the universe. Within the class of cold dark matter models, we find that the overall fractional energy density of the universe Omega is constrained to be 0.85=Omega=1.25 at the 68% confidence level. Combined with the COBE measurement, the data on degree scales from the Microwave Anisotropy Telescope in Chile, and the high-redshift supernovae data, we obtain new constraints on the fractional matter density and the cosmological constant. 相似文献
8.
9.
Oscar Agertz George Lake Romain Teyssier Ben Moore Lucio Mayer Alessandro B. Romeo 《Monthly notices of the Royal Astronomical Society》2009,392(1):294-308
Observations of turbulent velocity dispersions in the H i component of galactic discs show a characteristic floor in galaxies with low star formation rates and within individual galaxies the dispersion profiles decline with radius. We carry out several high-resolution adaptive mesh simulations of gaseous discs embedded within dark matter haloes to explore the roles of cooling, star formation, feedback, shearing motions and baryon fraction in driving turbulent motions. In all simulations the disc slowly cools until gravitational and thermal instabilities give rise to a multiphase medium in which a large population of dense self-gravitating cold clouds are embedded within a warm gaseous phase that forms through shock heating. The diffuse gas is highly turbulent and is an outcome of large-scale driving of global non-axisymmetric modes as well as cloud–cloud tidal interactions and merging. At low star formation rates these processes alone can explain the observed H i velocity dispersion profiles and the characteristic value of ∼10 km s−1 observed within a wide range of disc galaxies. Supernovae feedback creates a significant hot gaseous phase and is an important driver of turbulence in galaxies with a star formation rate per unit area ≳10−3 M⊙ yr−1 kpc−2 . 相似文献
10.
Influence of lunar phases,winds and seasonality on the stranding of mesopelagic fish in the Strait of Messina (Central Mediterranean Sea) 下载免费PDF全文
Pietro Battaglia Giovanni Ammendolia Mauro Cavallaro Pierpaolo Consoli Valentina Esposito Danilo Malara Ignazio Rao Teresa Romeo Franco Andaloro 《Marine Ecology》2017,38(5)
The shore stranding of mesopelagic fauna is a recurrent phenomenon in the Strait of Messina (Central Mediterranean Sea). The aim of this paper is to test the influence of lunar phases, winds and seasons upon the frequency of occurrence of strandings of mesopelagic fish. Species abundance in relation to these factors was quantified for the first time. Specimens were collected stranded on the shore along the Sicilian coast of the Strait of Messina between 2008 and 2016. Overall 32 species belonging to seven families (Gonostomatidae, Microstomatidae, Myctophidae, Paralepididae, Phosichthyidae, Sternoptychidae, Stomiidae) were found stranded. Myctophidae was the family including the highest number of species (16), whereas Gonostomatidae was the most abundant in terms of total number of individuals (47.2%), mainly thanks to the species Cyclothone braueri. The moon, which influences the strength of currents (highest during full and new moon phases) and irradiance (higher in some lunar phases, such as the full moon), affected the abundance of stranded mesopelagic fish in the study area. The highest number of stranding events was recorded during the new moon: 34.6% of the total relative abundance of stranded mesopelagic fish. Wind blowing from the sea towards the coastline (southeasterly and easterly winds) created the best conditions for strandings. The highest abundance of stranded specimens was recorded during the winter season. 相似文献