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291.
Over the last two decades, the global production of farm-raised shrimps has increased at a faster rate than any other aquacultural product, leading to massive socio-ecological damages in the mangrove areas where shrimp farming often takes place. Consequently, an increasing number of conflicts pitting coastal populations against shrimp farmers has been reported although very few conflicts have been studied in detail. This article contributes to fill this research gap by analyzing the causes, development and consequences of one such conflict in the Ecuadorian canton of Muisne (province of Esmeraldas). This conflict is one of the world's earliest and most important protest movements for the defence of mangroves and against the shrimp industry. Within a political ecology perspective, we connect three key dimensions of the conflict: (1) the socioeconomic metabolism of shrimp farming locally and internationally, (2) the institutions – formal and informal – that regulate the access to mangroves, and (3) the development of the mobilization itself, with special reference to the role of local women. The study is based on six-month fieldwork and combines data from 52 in-depth interviews of a wide range of actors, various documentation, and direct and participant observation. We find that the development of shrimp farming can be understood as a modern case of enclosure movement whereby customary community mangroves are privatized for the building of shrimp ponds. As a result, local mangrove-dependant populations – especially women – mobilized with the support of a grassroots Environmental Justice Organization. The protest was targeted at a form of ecologically unequal exchange where sectors of the global North shift socio-ecological costs onto poor sectors of the producing regions of the global South. In agreement with feminist political ecology, local women were particularly resistant to this process of ‘accumulation by dispossession’. While only some mangroves could be saved or reforested as a result of the movement, women's mobilization has had the unexpected effect of challenging gender relations in their communities. This research articulates dimensions of a given conflict that are too often considered separately, namely social-metabolic issues, institutional change, and gender issues. This allows a more comprehensive view of a complex power struggle. 相似文献
292.
293.
Moisture Movement Through Cracked Clay Soil Profiles 总被引:1,自引:0,他引:1
Delwyn G. Fredlund Sandra L. Houston Quan Nguyen Murray D. Fredlund 《Geotechnical and Geological Engineering》2010,28(6):865-888
A continuum mechanics approach is used for the formulation of unsaturated hydraulic conductivity functions and the water storage
functions for fractured or cracked clay soils in this parametric study. Suggested procedures are based on available research
literature related to the behavior of cracked unsaturated porous media. The soil–water characteristic curve, hydraulic conductivity
and water storage functions take on the character of bi-modal unsaturated soil property functions. The bimodal character arises
out of the independent behavior of the cracks and the intact clay soil. Matric suction changes beneath a slab-on-grade foundation
placed on a cracked clay soil profile are modeled for varied surface flux conditions using the proposed unsaturated hydraulic
conductivity and water storage functions. The impact of various levels of surface cracking on soil suction distributions is
discussed. Suction distribution patterns are dependent on the initial soil surface suction. In particular, the results are
dependent upon whether the initial matric suction is less than or greater than the air entry of the cracked clay. There is
an extremely wide range of possible conditions that could be modeled but the parametric study results presented in this paper
are limited to a series of selected crack widths and densities for an exfiltration case and an infiltration case. 相似文献
294.
295.
Jorge Marcovecchio Sandra Botté Melisa Fernández Severini Federico Delucchi 《Aquatic Geochemistry》2010,16(2):251-266
Chromium and lead concentrations and distribution have been fully studied within Bahía Blanca estuary inner area, which is
strongly influenced by urban and industrial stress. Not only metals dissolved in estuarine water but also those included in
sediments and suspended particulate matters (SPM) were measured. In all cases, internationally standardized protocols were
applied to metal measurements, including analytical quality check test through analysis of certified reference materials.
Total metal contents from surface sediments and SPM were compared with those from a historical database of the area, as well
as with values representing the natural geochemical baseline within the system. Results showed that heavy metal pollution
is mainly localized in the areas close to both industrial effluents discharge system and urban sewage outfall discharge. Data
from sequential extractions indicate that metals from anthropogenic sources (i.e., Pb) are potentially more mobile than those
inherited from geological parent material (i.e., Cr). The influences of other potential sources of metals (i.e., streams,
runoff) were also considered. SPM was clearly identified as the main carrier of the studied heavy metals within the system,
and its significance to metals input into sediments and/or biota was verified. Finally, the normalization of measured metal
concentrations against background reference elements (i.e., Al or Fe) has allowed to identify that most of the measured Cr
was lithogenic, while a significant percentage of Pb was from anthropogenic origin within Bahía Blanca estuary. 相似文献
296.
Depth-dependent sampling to identify short-circuit pathways to public-supply wells in multiple aquifer settings in the United States 总被引:3,自引:2,他引:1
Matthew K. Landon Bryant C. Jurgens Brian G. Katz Sandra M. Eberts Karen R. Burow Christy A. Crandall 《Hydrogeology Journal》2010,18(3):577-593
Depth-dependent water-quality and borehole flow data were used to determine where and how contamination enters public-supply wells (PSWs) at study sites in different principal aquifers of the United States. At each of three study sites, depth-dependent samples and wellbore flow data were collected from multiple depths in selected PSWs under pumping conditions. The chemistry of these depth-dependent samples, along with samples of the surface discharge from the PSWs, was compared to that of adjacent nested monitoring wells. The results of depth-dependent analyses from sites in Modesto (California), York (Nebraska), and Tampa (Florida) are summarized and compared. Although the exact mechanisms for transport of contaminants to the PSWs varied among these hydrogeologic settings, in all three settings the presence of wells or boreholes or natural preferential flow paths allowed water and contaminants to bypass substantial portions of the aquifer and to reach PSWs or depths in the aquifer more quickly than would have occurred in the absence of these short-circuiting flow paths. The chemistry and flow data from multiple depths was essential to developing an understanding of the dominant flow paths of contaminants to PSW in all three settings. This knowledge contributes to developing effective strategies for monitoring and protection. 相似文献
297.
Robert Barouki Manolis Kogevinas Karine Audouze Kristine Belesova Ake Bergman Linda Birnbaum Sandra Boekhold Sebastien Denys Celine Desseille Elina Drakvik Howard Frumkin Jeanne Garric Delphine Destoumieux-Garzon Andrew Haines Anke Huss Genon Jensen Spyros Karakitsios Jana Klanova Iida-Maria Koskela Francine Laden Paolo Vineis 《Chemie der Erde / Geochemistry》2010
The outbreak of COVID-19 raised numerous questions on the interactions between the occurrence of new infections, the environment, climate and health. The European Union requested the H2020 HERA project which aims at setting priorities in research on environment, climate and health, to identify relevant research needs regarding Covid-19. The emergence and spread of SARS-CoV-2 appears to be related to urbanization, habitat destruction, live animal trade, intensive livestock farming and global travel. The contribution of climate and air pollution requires additional studies. Importantly, the severity of COVID-19 depends on the interactions between the viral infection, ageing and chronic diseases such as metabolic, respiratory and cardiovascular diseases and obesity which are themselves influenced by environmental stressors. The mechanisms of these interactions deserve additional scrutiny. Both the pandemic and the social response to the disease have elicited an array of behavioural and societal changes that may remain long after the pandemic and that may have long term health effects including on mental health. Recovery plans are currently being discussed or implemented and the environmental and health impacts of those plans are not clearly foreseen. Clearly, COVID-19 will have a long-lasting impact on the environmental health field and will open new research perspectives and policy needs. 相似文献
298.
299.
Robert M. Haberle Francois Forget James Head Melinda A. Kahre Mikhail Kreslavsky Sandra J. Owen 《Icarus》2013,222(1):415-418
This note summarizes the results from the Mars recent climate change workshop at NASA/Ames Research Center, May 15–17, 2012. 相似文献
300.
Remote sensing-based assessment of tsunami vulnerability and risk in Alexandria, Egypt 总被引:1,自引:0,他引:1
Sandra Eckert Robert Jelinek Elisabeth Krausmann 《Applied geography (Sevenoaks, England)》2012,32(2):714-723
Tsunamis can cause catastrophic loss of life, destruction of property, engineered structures and coastal infrastructure, and they can lead to major economic losses. Even though tsunamis are relatively rare in the Mediterranean Sea, their potential danger to cities along the Mediterranean coast cannot be neglected. In order to create awareness among the potentially affected people it is important to know the risk and vulnerability of the population and infrastructure related to a possible tsunami impact. In this work a hazard, vulnerability and risk analysis for buildings in two districts of Alexandria was carried out. Relevant input parameters were derived mainly from remote sensing and field data and were analyzed with a geographical information system (GIS). Based on historical records of past tsunamis, two inundation scenarios of 5 m and 9 m were defined and modeled applying a bath-type model. The resulting tsunami building risk zone maps showed that 12% of the buildings in El Gomrok district are at high or very high risk for the 5 m scenario, while the risk for El Montazah area is low. For the 9 m scenario, on the other hand, the majority of the buildings in both districts, 56% of El Gomrok, and 60% of El Montazah, are in the high or very high risk zone. An analysis of the building use indicated that the majority of these buildings are residential and commercial types, highlighting that the potential consequences of a tsunami could be severe. Due to the scarcity of historical data no frequency could be associated with the two selected scenarios. While both are credible we consider the 5 m scenario as possible but unlikely and the 9 m scenario as unlikely. 相似文献