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1.
Mohamed Chaker Raddadi Annie Arnaud Vanneau Grard Poupeau Elisabeth Carrio-Schaffhauser Hubert Arnaud Alice Rivera 《Comptes Rendus Geoscience》2005,337(16):96
High gamma-radioactivity in carbonates is usually ascribed to uranium of detrital minerals and organic matter, and to thorium and potassium of clays. The present study based on Urgonian marls and marly limestones (France) shows that some of the most radioactive values correspond instead to some ‘pure’ limestones. These peaks are generally associated with a sequence boundary or a maximum flooding surface. Low-level γ-spectrometry and ICP–MS analyses show that although high radioactivities are mostly associated with uranium, there is no obvious correlation between uranium enrichment and lithology. Also, correlation between high radioactivity and argillaceous beds might not be systematic. To cite this article: M.C. Raddadi et al., C. R. Geoscience 337 (2005). 相似文献
2.
Sara Teitelbaum Annie Montpetit Jean-François Bissonnette Clément Chion Guy Chiasson Frédérik Doyon 《社会与自然资源》2019,32(1):93-112
This article explores the suitability of Ostrom and colleagues' social-ecological systems framework (SESF) for the study of resource-dependent communities in Canada. Through a broad literature about resource-dependent communities in Canada, three main approaches are identified, named staples research, rural development, and sustainability studies. Each of these research traditions is analyzed with regards to a common set of criteria – focus, scale, methods, treatment of institutions, and treatment of environmental dimensions. Research in each category is compared and contrasted with the SESF approach, to identify areas of overlap and divergence. Results indicate that the SESF is unlikely to provide additional benefit in terms of in-depth of social analysis, however, it does provide a unique contribution in terms of its coupled approach to conceiving social and ecological systems and its ability to operationalize these relationships through structured variables. 相似文献
3.
4.
Anne-Marie Lézine Augustin F.-C. Holl Judicaël Lebamba Annie Vincens Chimène Assi-Khaudjis Louis Février Émmanuelle Sultan 《Comptes Rendus Geoscience》2013,345(7-8):327-335
This paper discusses the relationship between patterns of human settlements and environmental change during the Holocene along the northwestern margins of the equatorial rain forest of central Africa. Palaeoenvironmental data from high-resolution sediment cores from lacustrine deposits, plant macro-remains from forest soils, and archaeological data are harnessed to discuss the differential impact of climate and/or humans on the central African rain forest. It is shown that climate change impacted the rain forest well before the widespread expansion of human settlements all over the study area. 相似文献
5.
6.
Article 2 of the UN Framework Convention on Climate Change (UNFCCC), which states the treaty's long-term objective, is the
subject of a growing literature that examines means to interpret and implement this provision. Here we provide context for
these studies by exploring the intertwined scientific, legal, economic, and political history of Article 2. We review proposed
definitions for “dangerous anthropogenic interference” and frameworks that have been proposed for implementing these definitions.
Specific examples of dangerous climate changes suggest limits on global warming ranging from 1 to 4 ∘C and on concentrations ranging from 450 to 700 ppm CO2 equivalents. The implications of Article 2 for near term restrictions on greenhouse-gas emissions, e.g., the Kyoto Protocol,
are also discussed. 相似文献
7.
Annie G. BHOWMIK 《国际泥沙研究》1999,(2)
1INTRODUCTIONTheUpperMississippiRiver(U-MR)extendsfromCairo,Illinois,totheheadwaiersoftheMississippiRiver(MR)nearLakeltascainMinnesota.Theentirerivercanbedividedintotwomajorreachesf1)theUpperMississippiRiverfromheadwaierstoCairo,Illinois,totheconfluenceoftheOhioRiverwiththeMississippiRiver,and2)theLowerMississippiRiver(LMR)fromCairo,Illinois,totheGulfofMexico.FigureIshowsthisdivision,includingabreakdownoftheentireriverintofive(5)segmentswhichwillbedescribedinasubsequentsectio… 相似文献
8.
Fiona Miller Annie Bolitho Natalie Jamieson Charlotte Catmur Anna Hurlimann Kathryn Bowen 《The Australian geographer》2014,45(1):19-35
Drawing upon theory from the field of urban political ecology, we analyse a major strategic water plan for Melbourne, Australia—the Sustainable water strategy for the Central Region, published in 2006. We assess the extent to which the strategy identified and addressed ecological sustainability in terms of: cultural frames; ecological context; social equity; and engagement processes. We identify that the strategy's framing of water was largely separate from its social and ecological context. This framing resulted in the importance of issues such as environmental flows, social equity and cultural values being diminished, thus avoiding the inevitable confrontation with environmental limits needed to ensure long-term ecological sustainability. Our analysis shows that the discursive dominance of economics limited the response to persuasive scientific arguments for greater ecological consideration in the strategy. Our findings suggest that broadening engagement with the diverse ways in which water is valued is likely to contribute to more equitable and ecologically sustainable water futures. 相似文献
9.
Annie Souriau Alfred Piuzzi Micheline Etchegorry Philippe Machetel 《Journal of Geodesy》1984,58(1):53-72
One of the possibilities of the Doppler positioning from satellite is to provide geodetic measurements continuous in time
without the need for reference stations. If measurements of sufficient accuracy can be achieved they may be used to study
local surface displacements in relation to tectonic activity. A Doppler receiver of the MEDOC network is located near Djibouti
in the Ghoubhat-Asal rift region which corresponds to the accreting plate boundary between the Arabian and African plates.
In November 1978, a seismic and volcanic crisis occured in this area. Surface geodetic measurements and levellings performed
in 1973 and 1978–79, just after the crisis, reveal a 60–80 cm sinking of the graben floor and a lateral extension of about
2 meters.
Here we analyse Doppler measurements for the period January 1977 to November 1980. Point positions are computed for 7 to 10
day intervals using a precise ephemeris, and a moving window analysis is applied to the data. An apparent 2 meter uplift preceding
the November 1978 seismic crisis is detected at Djibouti, whereas no similar phenomenon is observed at the two closest stations,
Pretoria and Uccle-Brussels. However, field observations rule out a tectonic origin for this uplift.
In Djibouti, the correlation between the apparent vertical station position and the electron density in the ionospheric F-layer
reveals that a bias may be induced by the third order term of the ionospheric refractive index not previously taken into account,
or more probably by the ray curvature through the ionosphere. This bias is particularly strong for our data set, from a station
located close to the magnetic equator, and related to a period of rapid increase in the solar activity.
Although our analysis fails to detect any tectonic displacement related to the rift seismic activity, it shows that similar
tectonic studies by the Doppler method will be possible once the residual ionospheric errors are removed, for example by use
of higher radio frequencies. 相似文献
10.
Protracted oogenesis and annual reproductive periodicity in the deep‐sea pennatulacean Halipteris finmarchica (Anthozoa,Octocorallia) 下载免费PDF全文
Halipteris finmarchica is one of the most common species of deep‐sea pennatulacean corals in the Northwest Atlantic; it was recently determined to act as a biogenic substrate for other species and as a nursery for fish larvae. Its reproductive cycle was investigated in colonies sampled in 2006 and 2007 along the continental slope of Newfoundland and Labrador (Canada). Halipteris finmarchica exhibits large oocytes (maximum diameter of 1000 μm), which are consistent with lecithotrophic larval development. Female potential fecundity based on mature oocytes just before spawning was ~6 oocytes · polyp?1 (500–6300 oocytes · colony?1); male potential fecundity was 16 spermatocysts · polyp?1 (5500–57,400 spermatocysts · colony?1). Based on statistical analysis of size‐probability frequency distributions, males harboured one cohort of spermatocysts that matured inside 8–11 months, whereas females harboured two distinct cohorts of oocytes; a persistent pool of small ones (≤400 μm) and a small number (~20%) of larger ones that grew from ~400 to >800 μm over a year. Despite this difference in the tempo of oogenesis and spermatogenesis, a synchronic annual spawning was detected. A latitudinal shift in the spawning period occurred from south (April in the Laurentian Channel) to north (May in Grand Banks and July–August in Labrador/Lower Arctic), following the development of the phytoplankton bloom (i.e. sinking of phytodetritus). Prolonged oogenesis with the simultaneous presence of different oocyte classes in a given polyp is likely not uncommon in deep‐sea octocorals and could hamper the detection of annual/seasonal reproduction when sample sizes are low and/or time series discontinued or brief. 相似文献