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Energetic materials contamination was investigated at the former Explosives Factory Maribyrnong, Victoria, Australia. Spectrophotometric/high performance liquid chromatography (HPLC) analysis was utilised to delineate a 5 tonne crystalline 2,4,6-trinitrotoluene (TNT) source in a former process waste lagoon that was found to be supplying contaminant leachate to the surficial clay aquitard with a maximum-recorded concentration of 7.0 ppm TNT. Groundwater within underlying sand and gravel aquifers was found to be uncontaminated due to upward hydraulic gradients resulting in slow plume development and propagation. Adsorption and microcosm test results from a parallel study were used as input parameters to simulate aqueous TNT transport in the clay aquitard using ATRANS20 software. The simulated TNT plume was localised within a few metres of the source, and at steady state, though leaching rate calculations suggest that without mitigation or other changes to the system, persistence of the source would be approximately 2,000 years. Remediation strategies may involve removal of the near surface source zone and infilling with an impermeable capping to impede leaching while facilitating ongoing natural attenuation by anaerobic degradation.  相似文献   
174.
We developed a model to estimate seismic vulnerability of health facilities in Mexico City, Mexico, following these steps: (1) designing a theoretical framework (TF) to measure structural, non-structural, functional, and administrative-organizational vulnerabilities; (2) measurement of the vulnerability conditions of the analyzed facility by using the TF; and (3) estimation of the hospital’s seismic vulnerability by comparing the measured vulnerability to the TF’s vulnerability indicators by taking into account the optimal case. The TF was developed considering a scoring system and international standards for risk management in hospitals. The methodology establishes the degree of vulnerability of the analyzed institution as well as its interrelations with external infrastructure systems. This tool also identifies existing failures to estimate expected damage. The methodology was applied to the National Cardiology Hospital, the Children’s Hospital “Dr. Federico Gómez,” and the “Hospital de Jesus” of Mexico City. The vulnerability problems in these three hospitals are common within them, and some of the main causes of vulnerability found are: (1) the lack of technology to resistant seismic shaking; (2) the need to develop or update disaster response plans; (3) the need of periodic and proper maintenance to hospitals’ buildings; (4) the lack of sufficient financial resources for vulnerability reduction projects and autonomous operations of the hospital during 3–5 days after a disaster occurs. We believe that vulnerability in these health facilities can be reduced with low-cost procedures and that the methodology developed here will support the decision-making processes to reduce seismic risk in Mexico City.  相似文献   
175.
Public scepticism surrounding climate change is an obstacle for implementing climate change mitigation measures in many countries. However, very little is known about: (1) the nature and sources of climate change scepticism; and (2) its influence on preferences for climate change mitigation policies. In this paper, we investigate these two issues using evidence and analysis from an Australian public survey and choice experiment. The study has three key findings. First, the intensity of scepticism varies depending on its type; we observed little scepticism over the cause, trend and impact of climate change and widespread scepticism over the effectiveness of mitigation measures and global co-operation. Second, cause and mitigation scepticism play significant roles in determining public support for climate change abatement. Respondents who believed in human-induced climate change were significantly more supportive of mitigation. Likewise, respondents who believed that mitigation would be successful in slowing down climate change were significantly more likely to be supportive. Third, the general public tend to give the benefit of the doubt to supporting mitigation. Those who expressed higher uncertainty about climate outcomes were more supportive of mitigation than others with similar expectations but lower uncertainty.  相似文献   
176.
Indigenous peoples offer alternative knowledge about climate variability and change based on their own locally developed knowledges and practices of resource use. In this article we discuss the role of traditional ecological knowledge in monitoring and adapting to changing environmental conditions. Our case study documents a project to record the seasonal knowledge of the Miriwoong people in northern Australia. The study demonstrates how indigenous groups’ accumulate detailed baseline information about their environment to guide their resource use and management, and develop worldviews and cultural values associated with this knowledge. We highlight how traditional ecological knowledge plays a critical role in mediating indigenous individuals and communities’ understandings of environmental changes in the East Kimberley region of north-west Australia, and how these beliefs may influence future decision-making about how to go about adapting to climate change at a local level.  相似文献   
177.
We reconstructed the long‐term spruce budworm (SBW) (Choristoneura fumiferana Clem.) outbreak dynamics in the boreal forest of Quebec (Canada) using a dendrochronological approach with subfossil trees. Although the majority of the excavated wood belonging to the genus Picea could potentially reveal the past activity of spruce budworms in the tree rings, very few were cross‐dated due to a lack of marker rings. All cross‐dated trees were found within a particular zone of the peat bogs and the floating chronology was radiocarbon dated to ca. 5.1 cal ka BP. The results presented in this study suggest that the dynamics of SBW outbreaks in the studied area fluctuated during the last millennia and that severe outbreaks as observed during the 20th century seldom occurred in that part of the boreal forest since the end of the last glaciation. These results are in agreement with observations from other parts of eastern North America. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
178.
Inbreeding depression strongly affects the biological fitness of organisms throughout their life cycle. These negative effects are more pronounced in species with low dispersal potentials, where mating among relatives is more likely. However, in some species, an outbreeding depression could be expressed when local adaptive and genetic beneficial interactions are disrupted when mating occurs between individuals from different localities. The amphipod Orchestoidea tuberculata inhabits the upper level of sandy beaches. This species has direct development and adults are poor swimmers, resulting in low dispersal potential. We herein evaluated potential inbreeding and outbreeding depression responses in O. tuberculata estimated in fecundity, egg size, and mate choice. Artificial families were used with individuals from different sites within a single beach and from distinct beaches. Results showed that the highest fecundity (66.7%) and the largest egg size (50.1 mm3) were recorded in females that mated with males from the same site, rather than males from other sites and beaches. We also observed potential recognition mechanisms that clearly favored inbreeding (81.8% of males chose females from the same site). These results suggest a potential outbreeding depression in O. tuberculata. Additional studies are needed to elucidate underlying adaptive mechanisms favoring inbreeding in this species.  相似文献   
179.
Cell-Fe(III) mineral aggregates produced by anoxygenic Fe(II)-oxidizing photoautotrophic microorganisms (photoferrotrophs) may be influential in the modern Fe cycle and were likely an integral part of ancient biogeochemical cycles on early Earth. While studies have focused on the environmental conditions under which modern photoferrotrophs grow and the kinetics, physiology and mechanism of Fe(II) oxidation, no systematic analyses of the physico-chemical characteristics of those aggregates, such as shape, size, density and chemical composition, have as yet been conducted. Herein, experimental results show most aggregates are bulbous or ragged in shape, with an average particle size of 10-40 μm, and densities that typically range between 2.0 and 2.4 g/cm3; the cell fraction of the aggregates increased and their density decreased with initial Fe(II) concentration. The mineralogy of the ferric iron phase depended on the composition of the medium: goethite formed in cultures grown by oxidation of dissolved Fe(II) medium in the presence of low phosphate concentrations, while poorly ordered ferrihydrite (or Fe(III) phosphates) formed when amorphous Fe(II) minerals (Fe(II)-phosphates) and high concentrations of phosphate were initially present. Importantly, in all experiments, a fraction of the photoautotrophic cells remained planktonic, demonstrating a constant stoichiometric excess of Fe(III) compared to the autotrophically fixed carbon in the biogenic precipitate. These results not only have an important bearing on nutrient and trace element cycling in the modern water column, but the size, shape and composition of the aggregates can be used to estimate aggregate reactivity during sediment diagenesis over short and geologic time scales.  相似文献   
180.
Intra-annual link of spring and autumn precipitation over France   总被引:2,自引:0,他引:2  
In a previous study, an intra-annual relationship of observed precipitation, manifested by negative correlations between domain-averaged spring and autumn precipitation of the same year, was found in two domains covering France and Central Europe for the period 1972–1990 (Hirschi et al., J Geophys Res 112(D22109), 2007). Here, this link and its temporal evolution over France during the twentieth century is further investigated and related to the atmospheric circulation and North Atlantic/Mediterranean sea surface temperature (SST) patterns. Observational datasets of precipitation, mean sea level pressure (MSLP), atmospheric teleconnection patterns, and SST, as well as various global and regional climate model simulations are analyzed. The investigation of observed precipitation by means of a running correlation with a 30-year time window for the period 1901–present reveals a decreasing trend in the spring-to-autumn correlations, which become significantly negative in the second half of the twentieth century. These negative correlations are connected with similar spring-to-autumn correlations in observed MSLP, and with negatively correlated spring East Atlantic (EA) and autumn Scandinavian (SCA) teleconnection pattern indices. Maximum covariance analyses of SST with these atmospheric variables indicate that at least part of the identified spring-to-autumn link is mediated through SST, as spring precipitation and MSLP are connected with the same autumn SST pattern as are autumn precipitation, MSLP and the SCA pattern index. Except for ERA-40 driven regional climate models from the EU-FP6 project ENSEMBLES, the analyzed regional and global climate models, including Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) simulations, do not capture this observed variability in precipitation. This is associated with the failure of most models in simulating the observed correlations between spring and autumn MSLP. While the causes for the identified relationship cannot be fully established its timing suggests a possible link with increased aerosol loading in the global dimming period.  相似文献   
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