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101.
Exploited fish and shellfish stocks in European marine waters underlie the Common Fisheries Policy (CFP). The next round of reform of the CFP is due for completion in 2012. The exploitation at maximum sustainable yield (MSY) may be confirmed as the common environmental objective for good environment status (GES) of exploited fish and shellfish stocks of the reformed CFP and the Marine Strategy Framework Directive (MSFD). The foreseen time horizon to achieve or maintain GES by 2020 appears inconsistent with the World Summit on Sustainable Development UN agreement in 2002, which stipulates that maintenance or restoring of stocks to produce MSY be realized by 2015. The MSFD requires instead that by 2015 the national programmes of measures be designed in order to become operational the following year (2016). 相似文献
102.
Gert Oberheuser Hendrik Kathrein Guy Demortier Horst Gonska Friedemann Freund 《Geochimica et cosmochimica acta》1983,47(6):1117-1129
Carbon subsurface concentration profiles in olivine single crystals from San Carlos, Arizona, and the Sergebet Island. Red Sea, containing total carbon between 60–180 wt.-ppm, were analyzed by means of the 12C(d. p)13C nuclear reaction and by x-ray induced photoelectron spectroscopy (XPS) in combination with acid etching and with Ar+ ion sputtering respectively, between 200–930 K. The (d, p) analysis reveals equilibrium subsurface C profiles extending 1–2 μm or more into the bulk. Their steepness is a function of temperature. Typical mean C concentrations at 300 K in the resolvable layers, 0–0.6, 0.6–1.2, and 1.2–1.8 μm. are 1.8, and 0.6 wt.-%, corresponding to enrichment factors over the mean bulk C concentration of the order of 100, 40 and 30 respectively. In the topmost atomic layers analyzed by XPS the carbon is enriched by a factor of the order of 1000, decreasing with increasing temperature. The results suggest that the carbon is in a truly dissolved state and highly mobile, subject to a reversible subsurface segregation. Most probably local lattice strain associated with the solute C species provide the driving force for this diffusional process. The C diffusion coefficient was determined from the (d, p) data below 300 K: D= 10?13 exp(?7.8/RT) [m2· sec?1; KJ · mole?1] and from XPS data between 450–925 K: D = 10?14 exp(-6/RT) [m2 · sec?1; KJ · mole?1] The estimated error of the preexponential factors is ± one order of magnitude, that of the activation energies ±3.5 and ±2 KJ mole?1 respectively. 相似文献
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Prof. Dr. Friedemann Freund Dipl. Min. Rolf Knobel Dr. Heinz Wengeler Dipl. Min. Hendrik Kathrein Dipl. Min. Gert Oberheuser Dr. Rainer G. Schaefer 《International Journal of Earth Sciences》1982,71(1):1-21
The recent discovery that atomic carbon occurs plentiful in olivines from mantle-derived rocks opens new aspects for the chemical evolution of the early atmosphere and the origin of life. It has been shown conclusively that atomic carbon which is dissolved in the model oxide MgO is capable of reacting in an O2-free atmosphere with the lattice oxygen to give CO2 and with the lattice hydrogen, derived from OH–, to give a profuse variety of hydrocarbons.The diffusional processes and low temperature gas/solid interface reactions involved in these processes are expected to introduce, purely abiotically, isotope fractionation resulting in a13C enrichment of the CO2 fraction and in a13C depletion of the hydrocarbon fraction which may be confused with the12C/13C isotope fractionation along biological pathways.Atomic carbon dissolved in olivines and in basalts shows a similar behaviour and yields similar quantities as C in MgO: 1–2 mg/g CO2 and 25–100g/g hydrocarbons degassing between 400 and 1000 °C. On a geological scale this means that each cubic kilometer of basaltic magma degassing in an O2-free atmosphere has the capacity of sending off about 3–6·109 kg (2·109 m3) of CO2 and about 1–3·108 kg (2·108 m3) of hydrocarbons. The presence of water modifies the composition to give, among others, alcohols and organic acids.On the basis of these results we are led to the conclusion that the early atmosphere of the earth may have contained a very high concentration of abiotically formed organic compounds of great chemical complexity.
Presented in part at the meeting Precambrian Problems, Copenhagen, March 1981. 相似文献
Zusammenfassung Die Entdeckung des atomar gelösten Kohlenstoffs in Olivinen aus Mantelgesteinen führt zu neuen Vorstellungen über die Zusammensetzung der Uratmosphäre und Entwicklungsbedingungen des Lebens. Atomarer Kohlenstoff im MgO ist in der Lage, in einer O2-freien Atmosphäre mit dem Gittersauerstoff zu CO2 zu reagieren und mit dem aus OH– stammenden Gitterwasserstoff eine große Vielfalt von organischen Verbindungen zu bilden.Diffusionsprozesse und Gas-Festkörper-Austauschreaktionen, die an diesen Reaktionen beteiligt sind, führen nach ersten Untersuchungen zu einer13C-Anreicherung im CO2 und einer13C-Abreicherung bei den Kohlenwasserstoffen. Diese12C/13C-Fraktionierung ist gleichsinnig mit der biologischen12C/13C-Fraktionierung.Atomarer Kohlenstoff in Olivinen und Basalten zeigt ein sehr ähnliches Reaktionsverhalten wie im MgO und führt zu ähnlichen Reaktionsprodukten: 1–2 mg/g CO2 und 25–100g/g Kohlenwasserstoffe zwischen 400–1000 °C. Übertragen auf geologische Verhältnisse bedeutet dies, daß jeder km3 eines entgasenden basaltischen Magmas 3–6·109 kg (2·109 m3) CO2 und 1–3·108 kg (2·108 m3) abwüschen Kohlenwasserstoff abgeben kann. Die Anwesenheit von Wasser führt zur Bildung von Alkoholen und organischen Säuren. Diese Ergebnisse deuten darauf hin, daß die Uratmosphäre und die Ursuppe viel reicher waren als bisher angenommen an komplexen organischen Verbindungen, die rein thermisch entstanden sind.
Résumé La découverte du carbone atomique dans les olivines du manteau entraîne de nouvelles idées sur la composition de l'atmosphère originelle et sur les conditions du développement de la vie. Comme l'est le cas pour le MgO, le carbone atomique dans les olivines est capable de réagir, dans une atmosphère exempte de O2, avec l'oxygène du réseau cristallin en formant du CO2, et avec l'hydrogène provenant des groupements OH– du réseau, pour former une grande variété de composés organiques.Les processus de diffusion et d'échange gas-solide liés à ces réactions provoquent, d'après les premiers résultats, un enrichissement en13C dans le CO2 et un appauvrissement en13C dans les hydrocarbures formés. Ceci ressemble au fractionnement dû à des réactions biologiques.Le comportement du carbone atomique et sa réactivité se retrouvent dans les basaltes et les olivines. La gamme des produits de réaction et leur quantité ressemble à celle du MgO: 1–2 mg/g CO2 et 25–100g/g composés organiques. A l'échelle géologique ceci implique que chaque km3 de magma basaltique dégazé en contact avec une atmosphère exempte d'oxygène pouvait émettre 3–6·109 kg, soit 2·109 m3 de CO2 et 1–3·108 kg, soit 2·108 m3 d'hydrocarbures abiotiques. La présence d'eau entraîne la formation d'alcools et d'acides organiques.La conclusion tirée de ce travail indique que l'atmosphère originelle et la»soupe primordiale» étaient plus riches qu'on ne l'a admis jusqu'à présent en composés organiques dûs à des processus purement thermiques, et donc abiotiques.
. MgO , COg, -, , . , , — — 13 2 . 12/13 , . , , - : 1–2 / O2 25–100 / , 400–1000 . , 3–6·109 (2·109 3) 2 1– 3·108 (2·108 3) . . , , , , .
Presented in part at the meeting Precambrian Problems, Copenhagen, March 1981. 相似文献
105.
Johannes Hendrik Van der Merwe 《GeoJournal》1997,43(2):135-151
A computerised aid to the land use planning process is demonstrated on the urban edge of Cape Town, South Africa. Multi-criteria analysis is performed in the IDRISI GIS package to evaluate development suitability for four land use categories according to appropriately measured and weighted criteria. The four suitability images are then subjected to multi-objective land allocation to demarcate optimum locations for each land use type. The decision-making process entails execution of seven consecutive steps which are discussed in detail and applied in the case study. Technical decisions are rationalised and results displayed. The paper concludes with a call for the development of applications which can incorporate public participation in this type of decision-making process to ensure the wider acceptance of advanced GIS technology as appropriate technology. 相似文献
106.
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108.
Eric Schlosser Birger Bohn Theo Brauers Hans-Peter Dorn Hendrik Fuchs Rolf Häseler Andreas Hofzumahaus Frank Holland Franz Rohrer Lutz Olaf Rupp Manfred Siese Ralf Tillmann Andreas Wahner 《Journal of Atmospheric Chemistry》2007,56(2):187-205
At the atmosphere simulation chamber SAPHIR in Jülich both Laser-Induced Fluorescence Spectroscopy (LIF) and Long-Path Differential
Optical Laser Absorption Spectroscopy (DOAS) are operational for the detection of OH radicals at tropospheric levels. The
two different spectroscopic techniques were compared within the controlled environment of SAPHIR based on all simultaneous
measurements acquired in 2003 (13 days). Hydroxyl radicals were scavenged by added CO during four of these days in order to
experimentally check the calculated precisions at the detection limit. LIF measurements have a higher precision (σ= 0.88×106 cm–3) and better time resolution (Δt = 60 s), but the DOAS method (σ= 1.24×106 cm–3, Δt = 135 s) is regarded as primary standard for comparisons because of its good accuracy. A high correlation coefficient of
r = 0.95 was found for the whole data set highlighting the advantage of using a simulation chamber. The data set consists of
two groups. The first one includes 3 days, where the LIF measurements yield (1 – 2) ×106 cm–3 higher OH concentrations than observed by the DOAS instrument. The experimental conditions during these days are characterized
by increased NOx concentration and a small dynamic range in OH. Excellent agreement is found within the other group of 6 days. The regression
to the combined data of this large group yields unity slope without a significant offset. 相似文献
109.
Core and surface sediments from the Tonalli River, a tributary of the artificial lake, Lake Burragorang, in the Blue Mountains National Park, New South Wales, Australia, were studied to evaluate the spatio-temporal distribution of pollutants from the Yerranderie silver-lead-zinc mine site, abandoned in the late 1920s. A sediment core was collected in the mouth of the Tonalli River, at its junction with Lake Burragorang, and surface sediment samples were collected in the Tonalli River and its tributaries. The concentrations of Pb, As, Zn, Cu, Cd, Hg and Ag in the sediments were determined by ICP-MS and ICP-AES techniques. Temporal variability of metal concentrations was established through 210Pb dating of the core sediments and compared with published historical records, rainfall records and bushfire data. Metal concentrations in core sediments showed an overall increase around the year 1950 as well as increases coincident with heavy rainfall. Spatially, metal concentrations were up to 400 times the guideline limit around mine sites but decreased rapidly with distance downstream of the mines. 相似文献
110.