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51.
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This special issue (SI) ‘A Tribute to Edward P. Glenn (1947-2017): A legacy of Scientific Environmental Assessment and Applications in Hydrological Processes’ is a celebration of the extensive work of Dr. Ed Glenn that was instrumental across multiple sub-disciplines of hydrology. The SI highlights four primary areas of hydrological processes that are cornerstones of Ed Glenn's over four decades of research. These contributions cover the following specialties: (i) Hydrology in the Colorado River Delta; (ii) Riparian ecosystem water use; (iii) Riparian Plant ecophysiology and ecohydrology; and (iv) Methods and models to characterize evapotranspiration. Since Ed was passionate about the dryland delta at the end of the Colorado River, we begin with four research studies that focus on this special region on the U.S.–Mexico border which encompasses four states (Baja and Sonora in Mexico and California and Arizona in United States) as well as tribal communities in the transboundary area. The Colorado River delta reaches the Northern Gulf of California in the Sea of Cortez which has been designated as a UNESCO international biosphere reserve (‘Reserva de la Biosfera El Pinacate y Gran Desierto de Altar’), which includes the Upper Gulf of California and Delta of the Colorado River (‘Reserva de la Biosfera Alto Golfo de California y Delta del Río Colorado’). Ed spent the majority of his last three decades on water balance studies and on ground-based transpiration quantification for validation of satellite and airborne remote sensing methods. We wrap up the special issue with contributions related to improving satellite and airborne remote sensing estimation of actual evapotranspiration. It is our pleasure to summarize the 16 research studies contributed to the special issue to honour Ed Glenn's research interests.  相似文献   
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Recently, evapotranspiration has been hypothesized to promote the secondary formation of calcium carbonate year‐round on tree islands in the Everglades by influencing groundwater ions concentrations. However, the role of recharge and evapotranspiration as drivers of shallow groundwater ion accumulation has not been investigated. The goal of this study is to develop a hydrologic model that predicts the chloride concentrations of shallow tree island groundwater and to determine the influence of overlying biomass and underlying geologic material on these concentrations. Groundwater and surface water levels and chloride concentrations were monitored on eight constructed tree islands at the Loxahatchee Impoundment Landscape Assessment (LILA) from 2007 to 2010. The tree islands at LILA were constructed predominately of peat, or of peat and limestone, and were planted with saplings of native tree species in 2006 and 2007. The model predicted low shallow groundwater chloride concentrations when inputs of regional groundwater and evapotranspiration‐to‐recharge rates were elevated, while low evapotranspiration‐to‐recharge rates resulted in a substantial increase of the chloride concentrations of the shallow groundwater. Modeling results indicated that evapotranspiration typically exceeded recharge on the older tree islands and those with a limestone lithology, which resulted in greater inputs of regional groundwater. A sensitivity analysis indicated the shallow groundwater chloride concentrations were most sensitive to alterations in specific yield during the wet season and hydraulic conductivity in the dry season. In conclusion, the inputs of rainfall, underlying hydrologic properties of tree islands sediments and forest structure may explain the variation in ion concentration seen across Everglades tree islands. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
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Wildfires are increasing in severity and frequency in the American West, but there is limited understanding of their economic effects at the community level. We conducted a case study of the impacts of large wildfires in 2008 in Trinity County, California, by examining labor market, suppression spending, and qualitative interview data. We found that the 2008 fires had interrelated effects on several economic sectors in the county. Labor market data indicated a decrease in total private-sector employment and wages and an increase in public-sector employment and wages during the summer of 2008 compared to the previous year, while interviews captured more nuanced impacts for individual businesses.  相似文献   
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Wildfire is one of several potential disturbances that could have extraordinary impacts on individuals and communities in fire-prone areas. In this article we describe disturbance risk perceptions from interviews with residents in three Florida communities that face significant wildfire and hurricane risk. Although they live in areas characterized by emergency managers as having high wildfire risk and many participants have direct experience with wildfire, residents tended to share high hurricane and low wildfire risk perceptions. The different perceptions of risk seem linked to several factors: direct hurricane experience, different scales of impact, the local “hurricane culture,” effectiveness of local ordinances and development patterns, perceived predictability of the event, and perceived ability to control the event. This study shows that residents may perceive and act to reduce risk for one disturbance in relation to their perceptions, concern, and actions for another.  相似文献   
56.
Three distinct types of microbial consortia appear to mediate the anaerobic oxidation of methane with sulfate as electron acceptor in marine sediments and are distributed ubiquitously. These consortia consist of ANerobic MEthanotrophic (ANME) archaea of the ANME-1, ANME-2 and ANME-3 clades and their sulfate-reducing bacterial partners either of the Desulfosarcina-Desulfococcus (ANME-1/DSS and ANME-2/DSS) or Desulfobulbus spp. (ANME-3/DBB) branches. Frequently one consortium type dominates the community, but the selective factors are not well constrained. Here we analyzed patterns in the composition of intact polar lipids extracted from bacterial and archaeal communities of different marine seep environments. Further, we investigated if different environmental and geographical factors were responsible for the observed patterns, and hence could be important in the selection of seep communities. Intact polar lipids (IPLs) provide a more robust distinction of the composition of extant communities than their less polar derivatives. In ANME-1/DSS-dominated communities, glycosidic- and phospho-glyceroldialkylglyceroltetraethers were abundant, while ANME-2/DSS and ANME-3/DBB-dominated communities showed abundant archaeol-based IPLs, either with glycosidic and phospho-headgroups or only phospho-headgroups, respectively. The relative proportion of bacterial IPLs varied widely from 0% to 93% and was generally lower in samples of the ANME-1 type, suggesting lower bacterial biomasses in the respective communities. In addition to these lipid signatures, distinctive features were related to the habitat characteristics of these communities: lower amounts of phosphate-based IPLs were generally observed in communities from calcified microbial mats compared to sediments, which may reflect phosphate limitation. Based on statistical analyses of IPLs and environmental data this study constrained for the first time the occurrence of three environmental factors controlling the distribution of different ANME-associated communities in a wide range of hydrocarbon seep systems. Habitats dominated by ANME-1/DSS communities were characterized by high temperature and low oxygen content in bottom waters (or even anoxia), while ANME-2/DSS and ANME-3/DBB-dominated sediments were located in settings with lower temperatures and higher oxygen content in bottom waters. Furthermore, ANME-2/DSS communities were particularly prominent in environments in which a relatively high supply of sulfate was sustained.  相似文献   
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Leachate-contaminated groundwater from historical municipal landfills, typically lacking engineered liners and leachate collection systems, poses a threat to nearby urban streams, particularly to benthic ecosystems. Effective monitoring and assessment of such sites requires understanding of the spatial patterns (i.e., two-dimensional footprint) of contaminated groundwater discharge and associated controlling factors. However, discharges from groundwater contaminated by modern wastewater can complicate site assessments. The objectives of this study were to (1) demonstrate the use of artificial sweeteners (AS): saccharin (SAC), cyclamate (CYC), acesulfame (ACE), and sucralose (SUC), to distinguish groundwater discharge areas influenced by historic landfill leachate (elevated SAC and sometimes CYC; low ACE and SUC concentrations) from those influenced by wastewater (high ACE and SUC concentrations), and (2) investigate contaminant discharge patterns for two gaining urban stream reaches adjacent historic landfills at base flows. Contaminant discharge patterns revealed by the AS were strongly controlled by hyporheic flow (low AS concentrations), particularly for the straight reach, and stream sinuosity, particularly for the meandering reach. These patterns were different and the contaminant footprint coverage (<25% of streambed area) much less than most past studies (typically >50% coverage), likely due to the homogeneous streambed-aquifer conditions and shallow, narrow landfill plume in this setting.  相似文献   
59.
Studies of living foraminiferal assemblages provide much information about their roles in present environments and a perspective on interpreting the past. Along modern coasts, benthic Foraminifera act as ecological indicators in their responses to different natural and anthropogenic conditions, such as food availability, oxygen concentrations, salinity, and trace metal concentrations. A detailed survey of foraminiferal populations was undertaken in the Mission-Aransas National Estuarine Research Reserve, Texas, close to the time of its establishment in 2006. The purpose was to gauge the overall status of populations and provide baseline data for future comparison. The arid south Texas Gulf Coast is a variable and often harsh environment where biota are subject to multiple anthropogenic stressors. Despite these rigors, living Foraminifera were prolific in the Reserve. This paper discusses the results from Mesquite (July 2008), Copano (May 2006), and Mission Bays (June 2006). Populations were robust in each bay, with Ammonia parkinsoniana, Ammotium salsum, and Elphidium excavatum being most abundant. Highest numbers corresponded mainly to areas of greater circulation. In Mission Bay, elemental analysis of shells, prompted by the presence of sulfur grains in sediments and by yellow tests, detected elevated levels of barium, strontium, and iron. Most sediment samples were black and sulfidic, and ubiquitous framboidal pyrite in sediment and shells suggests that forams were frequently subject to low-oxygen conditions. Abundant living numbers, tolerance of low-oxygen conditions, and the ability to cycle trace metals emphasize the resilience of Foraminifera in taxing environments and their integral position as lower trophic level members.  相似文献   
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