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91.
Florence L. Wong 《Geo-Marine Letters》1984,4(1):25-30
Amphiboles, orthopyroxenes, and clinopyroxenes dominate the heavy mineral suite of surficial sediments in lower Cook Inlet, Alaska. Sources for these sediments include the igneous arc terrane of the northeast Alaska Range, reworked intrabasinal sediments, and local drainages in lower Cook Inlet. The distribution of these deposits is a reflection of both the tidal currents and the prevailing southerly net movement from the head of Cook Inlet. The heavy mineral studies concur with similar findings from gravel analyses, clay mineral investigations, and quartz microtexture observations. 相似文献
92.
The hazard posed to aquatic organisms by exposure to aromatic amines will depend on their ability to activate or detoxify these potentially genotoxic compounds. We studied the metabolism of four aromatic amines (p-toluidine, aniline, 2-acetylaminofluorene (2-AAF) and 2-aminofluorene (2-AF)) in Bay mussels (Mytilus edulis) to gain an understanding of their metabolic capabilities in vivo. Mussels rapidly accumulated these compounds from the water column and depurated the majority of their steady-state body burdens as metabolites and unmetabolized parent compounds. The biotransformation pathways of [14C]-labeled parent compounds were determined by analyses of depurated metabolites and tissue residues. Biotransformation of p-toluidine and aniline resulted in the formation of their corresponding N-acetylated detoxification products. Mussels converted small amounts of 2-AAF into a deacetylated product (2-AF) and a mutagenically active metabolite (N-hydroxy-2-AF). 2-AF was extensively detoxified via N-acetylation, which limited the amount of primary amine available for activation. 相似文献
93.
Shelf break systems are highly dynamic environments. However little is known about the influence that benthic interactions and water mass mixing may have on vertical distributions of iron in these systems. Dissolved Fe (< 0.4 μm) concentrations were measured in samples from nine vertical profiles across the upper slope (150–2950 m water depth) at the Atlantic Ocean–Celtic Sea shelf break. Dissolved iron concentrations varied between less than 0.2 and 5.4 nM, and the resulting detailed section showed evidence of a range of processes influencing the Fe distributions. The near sea floor data were interpreted in terms of release and removal processes. The concentrations of dissolved Fe present in near seabed waters were consistent with release of Fe from in situ remineralisation of particulate organic matter at two upper slope stations, and possibly release from pore water upon resuspension on shelf. Lateral transport of dissolved iron was evident from elevated Fe concentrations in an intermediate nepheloid layer and its advection along isopycnals. Surface waters at the shelf break also showed evidence of vertical mixing of deeper iron-rich waters. These waters contained macronutrients that sustained primary productivity in these otherwise nutrient-depleted surface waters. The data also suggest some degree of stabilisation of relatively high concentrations of iron, presumably through ligand association or as colloids. This study supports the view that lateral export of dissolved iron to the interior of the ocean from shelf and coastal zones and may have important implications for the global budget of oceanic iron. 相似文献
94.
Gulati Sneh George Florence Hamid Shahid 《Theoretical and Applied Climatology》2018,131(3-4):1191-1202
Theoretical and Applied Climatology - Rising global temperatures are leading to an increase in the number of extreme events and losses ( http://www.epa.gov/climatechange/science/indicators/ ).... 相似文献
95.
F. P. Florence R. S. Darling S. E. Orrell 《Contributions to Mineralogy and Petrology》1995,121(4):424-436
Garnet-sillimanite-biotite gneiss near Port Leyden, in the western Adirondack Highlands, New York, contains mineral assemblages
and textures that formed during high temperature metamorphism and anatexis at mid-crustal pressures. Evidence for melting
includes thin, plagioclase-rich veins, sieve textures in biotite, and the presence of small, euhedral garnet neoblasts. Hercynite-silicate
equilibria in combination with the solidus for biotite dehydration melting indicate metamorphic pressure was between 4 and
6.4 kbar at the temperature of melting (ca. 735° C). The gneiss is intruded by a small, discordant Fe-Ti oxide-apatite (nelsonite)
dike. Reported field occurrences of nelsonite demonstrate its common association with anorthosite plutons. Although no anorthosite
bodies are exposed in the Port Leyden region, the presence of nelsonite is evidence of anorthositic magmatism in the western
Adirondacks. Post-intrusion metamorphism has caused partial apatite recrystallization and produced a weak foliated texture
in the dike. U-Pb ages from zircon and monazite from both the gneiss and the nelsonite dike indicate that these rocks experienced
a complex, polymetamorphic history that we interpret to reflect two thermal episodes. An older event is recorded by discordant
zircons in the gneiss, which indicate a minimum age of 1129±6 Ma. A linear best fit to the data yields an upper intercept
at 1166±53 Ma. This range of ages coincides with anorthosite-suite magmatism in the Adirondacks. A minimum zircon age of 1104±3 Ma
was obtained from the nelsonite dike. Lead-loss or late zircon crystallization at about 1020 Ma affected the U-Pb systematics
of zircon in the dike. Monazite ages from both rocks also indicate high temperature metamorphism (>700° C) between 1040 and
960 Ma. The older zircon ages and textural relations in the metapelite are viewed as evidence for anatexis at ca. 1150 Ma,
and the presence of nelsonite suggests that the intrusion of anorthosite was coincident with partial melting in the gneiss.
P-T estimates of metamorphism, therefore, imply that anorthosite was emplaced to about 15 km depth in the western Adirondack
Highlands.
Received: 13 September 1994 / Accepted: 10 May 1995 相似文献
96.
97.
Florence V. Dunkel Leanna M. Hansen Sarah J. Halvorson Arthur Bangert 《GeoJournal》2017,82(4):841-865
We assess women’s perceptions of health risks in relation to quality of life concerns, with attention to variables viewed as central to maintaining or improving health and well-being. In this paper, we specifically underscore how a life-threatening disease—malaria—is experienced and bio-cyclically understood and managed in relation to seasonal hunger, food insecurities, and livelihood vulnerabilities. The study, conducted June–July 2013, draws on field data and interviews with 60 women farmers of the Luhya community along the Yala River in Kakamega County, Western Province, Kenya. Major findings suggest the following: (1) women’s perceived desired quality of life is shaped by priorities for children’s education, nutrition, food security, and economic security in their rural communities; (2) malaria emerged as a challenging household health problem that curtails livelihood opportunities for most study participants; and (3) local understandings of malaria transmission, particularly how and when female mosquitoes become infected with malaria-causing protozoans, was low, but malaria symptoms were relatively well-understood. The interest and motivation to institute new malaria risk reduction practices at the community level are explored, including attention to building upon the Luhya tradition of oral storytelling in order to promote actions to eliminate malaria. This analysis of local narratives of health risks illustrates these points and demonstrates how women’s constructions of health risks and well-being provide a basis for developing interventions targeting income generation and microloan opportunities that could support Kenyan women in their intersecting approaches to malaria, securing nutritious diets, and enhancing the local health environment. 相似文献
98.
Residual circulation and stratification in the Liverpool Bay region of freshwater influence 总被引:1,自引:1,他引:0
Florence Verspecht Tom P. Rippeth John H. Simpson Alejandro J. Souza Hans Burchard M. John Howarth 《Ocean Dynamics》2009,59(5):765-779
Wind and tidal straining are proposed as key mechanisms influencing the magnitude and timing of the horizontal flux of freshwater
across regions of freshwater influence (ROFIs). Evidence for this hypothesis is presented in estimates of the tidally averaged
residual current profile, obtained from 5 years of continuous acoustic doppler current profiler measurements in the Liverpool
Bay ROFI. The modified horizontal Richardson number (RxwtR_{x}^{wt}), which includes both the tidal and the wind forcing, was assessed as a measure of stratification. RxwtR_{x}^{wt} was found to be a good indicator of the timing of the evolution and destruction of stratification, but was not as successful
as an indicator of the magnitude of stratification, both enduring and periodic. The observed mean residual velocities are
compared to those predicted by a classical solution, and the eddy viscosity (N
z
) is shown to be a control on differences between the observed and predicted circulation. Principal component analysis is
used to show that the strongest residual currents occur when the water column periodically alternates between a well-mixed
and stratified state, a consequence of straining, rather than simply related to the density gradient. Evidence of wind straining
was found in the correspondence between the wind direction and the near surface and near bed residual current direction. 相似文献
99.
Ika Paul-Pont Patrice Gonzalez Florence Jude Line Bourrasseau Frances Haynes Christine Paillard 《Marine pollution bulletin》2010,60(4):515-118
The present study evaluated the interactive effects of cadmium contamination and pathogenic organisms (trematodes Himasthla elongata and bacteria Vibrio tapetis) singularly and in combination during 7 days on the bivalve Cerastoderma edule. Some defense-related activities were analyzed such as genetic expression, metallothionein and immune responses. Trematode metacercarial infection, similar whatever the treatment, induced the strongest responses of immune parameters. Particularly, the interaction between cadmium and parasite exposures induced unusual responses on gene expression and immune responses. No effect of bacterial challenge appeared on bivalve responses, nevertheless a strong mortality of V. tapetis infected cockles occured between 7 and 14 days. Cadmium bioaccumulation was significantly modulated by both pathogenic organisms. Furthermore, an antagonistic effect of trematodes and bacteria was shown on metal bioaccumulation of co-infected cockles. These results highlighted the importance of considering the multiplicity of perturbation sources in coastal ecosystems to assess the health status of organisms. 相似文献