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排序方式: 共有148条查询结果,搜索用时 15 毫秒
101.
Sam Barrett 《Global Environmental Change》2013,23(6):1819-1829
Climate change creates a double inequality through the inverse distribution of risk and responsibility. Developed states are responsible, but are forecast to confront only moderate adverse effects; least developed states are not culpable and yet experience significant threats to livelihoods, assets and security. Adaptation finance addresses inequity by developed states facilitating/funding behaviour adjustments necessary for exposed communities to lessen climate risk. This article investigates the ground-level effectiveness of adaptation finance in climate vulnerable villages across Malawi, while controlling for disparities in vulnerability. Malawi and selected districts are both climate vulnerable and significant recipients of adaptation finance. This concludes a larger top–down multi-scalar analysis of climate justice, which applies the distribution and effectiveness of adaptation finance as a proxy. The study avails of participatory assessments to compare actions of villages receiving adaptation finance with those engaging in autonomous and informal adaptations. Adaptation finance villages: (a) address more climate related risks; and (b) enhance agency, security and sustainably lessen climate vulnerability. Conversely, informal practice villages attend to a lower proportion of climate risks and often develop short-term strategies with less enduring vulnerability reduction. Vulnerable communities receiving adaptation finance do change behaviours to reduce climate risk and thus secure local level climate justice. 相似文献
102.
Gemma Rueda Antoni Rosell-Melé Marina Escala Richard Gyllencreutz Jan Backman 《Organic Geochemistry》2009,40(2):287-291
Sea surface temperatures (SSTs) and annual mean air temperatures (MATs) are estimated for the last 200 years from glycerol dialkyl glycerol tetraethers (GDGTs) proxies in a marine sediment core from the Skagerrak, off southern Norway. The reconstructed values compare well with annual SSTs and summer air temperatures obtained from composite regional instrumental records. The results provide further confidence in the application of proxies based on GDGTs to estimate past temperatures. 相似文献
103.
104.
T.J. Barrett 《Earth and Planetary Science Letters》1980,49(2):193-204
In the Mesozoic eugeosynclinal sequences of the Italian North Apennines, ophiolitic rocks are commonly stratigraphically overlain by thick bedded chert sequences of Late Jurassic age. The isotopic composition of Pb contained in upper basalts, lower ferruginous (and in places manganiferous) cherts, middle cherts and upper cherts indicates that simple mixing occurred in the sediments between basalt-derived Pb, and more radiogenic Pb provided by fine-grained terrigenous detritus, radiolarian silica and possibly seawater.The most ferruginous cherts are those nearest the ophiolitic basement, which is interpreted as ocean crust formed early in the opening of the Apennine ocean. Hematite content, considered to represent original Fe hydroxy-oxide chemical precipitate in the sediment, decreases upwards in a general way to very low values in the upper cherts. The most ferruginous cherts also contain the highest volcanogenic Pb component and total Pb, whereas higher cherts contain mainly terrestrially-derived Pb. These relations indicate a volcanic-hydrothermal origin for a significant portion of the Pb in the basal to middle parts of the chert formation, and suggest a similar origin for the hematitic Fe. The vertical distribution of hematite and volcanogenic Pb suggests that some initial Fe precipitates, carrying such Pb, had a widespread lateral dispersal after formation at an active ridge. 相似文献
105.
Although satellite remote sensing of the atmosphere and Earth's surface has been pursued now for many years, it has not been applied widely in detailed or systematic investigations of the atmospheric and land surface climates of arid and semiarid regions. This paper briefly surveys characteristics of satellite systems that should be considered when evaluating the present and potential roles of satellite remote sensing in arid and semiarid zone research, and in studies of desertification. Actual and potential applications of satellite data in these research areas are then reviewed. It is concluded that satellite data available for arid and semiarid areas have been used in a very fragmentary and unsystematic manner. Proposals are made for exploiting more fully satellite data, especially in investigations of desertification. 相似文献
106.
Gemma Janer Sonia Mesia-Vela Margy L. Wintermyer Keith R. Cooper Fred C. Kauffman Cinta Porte 《Marine environmental research》2004,58(2-5):481
The esterification of two model vertebrate steroid hormones – estradiol (E2) and dehidroepiandrosterone (DHEA) – was studied in the oyster Crassostrea virginica. The activity of acyl-CoA:steroid acyltransferase was characterized in microsomal fractions isolated from oyster digestive glands. The apparent Km and Vmax values changed with the fatty acid acyl-CoA used (C20:4, C18:2, C18:1, C16:1, C18:0 or C16:0), and were in the range of 9–17 μM, and 35–74 pmol/min/mg protein for E2, and in the range of 45–120 μM, and 30–182 pmol/min/mg protein for DHEA. Kinetic parameters were also assessed in gonadal tissue. The enzyme saturated at similar concentrations, although conjugation rates were lower than in digestive gland. Preliminary data shows that tributyltin (TBT) in the low μM range (1–50) strongly inhibits E2 and DHEA esterification, the esterification of E2 being more sensitive to inhibition than that of DHEA. Overall, results indicate that apolar conjugation occurs in oysters, in both digestive gland and gonads, at a very similar rate to mammals, suggesting that this is a well conserved conjugation pathway during evolution. Esterification, together with other mechanisms, can modulate endogenous steroid levels in C. virginica, and might be a target for endocrine disrupters, such as TBT. 相似文献
107.
Diet studies of seabirds: a review and recommendations 总被引:8,自引:0,他引:8
108.
A Textural Record of Solidification and Cooling in the Skaergaard Intrusion, East Greenland 总被引:2,自引:0,他引:2
Holness Marian B.; Tegner Christian; Nielsen Troels F. D.; Stripp Gemma; Morse Stearns A. 《Journal of Petrology》2007,48(12):2359-2377
The clinopyroxene–plagioclase–plagioclase dihedralangle, cpp, in gabbroic cumulates records the time-integratedthermal history in the sub-solidus and provides a measure oftextural maturity. Variations in cpp through the Layered Seriesof the Skaergaard intrusion, East Greenland, demonstrate thatthe onset of crystallization of clinopyroxene (within LZa),Fe–Ti oxides (at the base of LZc) and apatite (at thebase of UZb) as liquidus phases in the bulk magma is recordedby a stepwise increase in textural maturity, related to an increasein the contribution of latent heat to the total heat loss tothe surroundings and a reduction in the specific cooling rateat the crystallization front of the intrusion. The onset ofboth liquidus Fe–Ti oxide and apatite crystallizationis marked by a transient increase in textural maturity, probablylinked to overstepping before nucleation. Textural maturationat pyroxene–plagioclase–plagioclase triple junctionseffectively ceases in the uppermost parts of the Layered Seriesas a result of the entire pluton cooling below the closure temperaturefor dihedral angle change, which is 1075°C. Solidificationof the Layered Series of the Skaergaard intrusion occurred viathe upwards propagation of a mush zone only a few metres thick. KEY WORDS: magma; partial melting; asthenosphere; olivine; mantle 相似文献
109.
Quantification of groundwater recharge in the city of Nottingham, UK 总被引:13,自引:3,他引:10
Groundwater is an important and valuable resource for water supply to cities. In order to make full and wise use of the asset
value, a clear understanding of the quantities and sources of urban groundwater recharge is needed. The water supply and disposal
network is often an important source of recharge to urban groundwater through leakage from water mains and sewers. An approach
to establishing the spatial and temporal amounts of the three urban recharge sources (precipitation, mains and sewers) is
developed and illustrated using the Nottingham (UK) urban aquifer. A calibrated groundwater flow model is supplemented by
calibrated solute balances for three conservative species (Cl, SO4 and total N), thus providing four lines of evidence to use in the recharge estimation. Nottingham is located on a Triassic
sandstone aquifer with average precipitation of 700 mm/year. Using the models, current urban recharge is estimated to be 211
mm/year, of which 138 mm/year (±40%) is from mains leakage and 10 mm/year (±100%) is from sewer leakage. The wide confidence
intervals result from the scarcity of historical field data and the long turnover time in this high volume aquifer, and should
be significantly lower for many other aquifer systems.
Received: 1 December 1997 · Accepted: 14 September 1998 相似文献
110.
On board short-time high temperature heat treatment of ballast water: a field trial under operational conditions 总被引:2,自引:1,他引:1
Quilez-Badia G McCollin T Josefsen KD Vourdachas A Gill ME Mesbahi E Frid CL 《Marine pollution bulletin》2008,56(1):127-135
A ballast water short-time high temperature heat treatment technique was applied on board a car-carrier during a voyage from Egypt to Belgium. Ballast water from three tanks was subjected for a few seconds to temperatures ranging from 55 degrees C to 80 degrees C. The water was heated using the vessel's heat exchanger steam and a second heat exchanger was used to pre-heat and cool down the water. The treatment was effective at causing mortality of bacteria, phytoplankton and zooplankton. The International Maritime Organization (IMO) standard was not agreed before this study was carried out, but comparing our results gives a broad indication that the IMO standard would have been met in some of the tests for the zooplankton, in all the tests for the phytoplankton; and probably on most occasions for the bacteria. Passing the water through the pump increased the kill rate but increasing the temperature above 55 degrees C did not improve the heat treatment's efficacy. 相似文献