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Middle and Upper Devonian deposits from the Aouinet Ouenine Formation in the southern Ghadames Basin of western Libya provide a well exposed example of a deltaic complex containing both progradational and transgressive facies. Progradational facies comprise both laterally accreting and incised distributary channels overlying prodelta deposits. Also present is a progradational beach environment showing build-up from an offshore shelf through nearshore shelf to shoreface and foreshore sub-environments. Over-lying these progradational facies are transgressive tidal-flat, washover-fan, foreshore and nearshore deposits.The characteristics and interrelationships of the different facies are explained by two sedimentation models: progradational facies existed contemporaneously during phases of active sediment supply whereas the transgressive facies existed contemporaneously during periods of diminished or absent detrital influx.  相似文献   
14.
The primary phases and minerals of the Plombières dumps include typical smelting furnace products such as metallic Fe, Pb, Cu, Zn, Fe-Zn alloys, carbides, phosphides, sulfides of Fe, Zn, Pb, Cu, Mn (alabandite), and FeAs. Spinels, mainly of Fe and Al, are common constituents of the primary assemblage; substitution by Zn, V, Cr, Ti, Mg, and Ca occurs. Primary phases also include the most common Zn-rich fayalite, Zn-rich Ca-Fe silicates, melilite, corundum, and apatite. Most of the Zn is incorporated in iron silicates, ZnO and ZnS. Lead occurs mainly as PbS, metallic lead, and is also present in coal residues. Cadmium is found mainly in metallic zinc and its alloys and in ZnO. The dumps also contain mining wastes composed of pyrite, melnikovite, and iron oxides produced by natural weathering of Zn-Pb ores. Melnikovite and iron oxides are rich in As, Pb, and Zn and possess an increased content of Tl. Leaching tests carried out on the surfaces of polished sections indicate that acid rain (solutions I and II) will mobilize mainly Zn and Cd and, to a much smaller extent, Pb and Sb. Leaching of metals by sulfate-chloride fluids present in the pore network of dumps (solutions III, IV, and V) depends on the pH, which in the dumps is controlled by the proportion of carbonates to sulfides. The more acid fluids leach both sulfides and silicates.  相似文献   
15.
This study explores the implications of shifting the narrative of climate policy evaluation from one of costs/benefits or economic growth to a message of improving social welfare. Focusing on the costs of mitigation and the associated impacts on gross domestic product (GDP) may translate into a widespread concern that a climate agreement will be very costly. This article considers the well-known Human Development Index (HDI) as an alternative criterion for judging the welfare effects of climate policy. We estimate what the maximum possible annual average increase in HDI welfare per tons of CO2 would be within the carbon budget associated with limiting warming to 2°C over the period 2015–2050. Emission pathways are determined by a policy that allows the HDI of poor countries and their emissions to increase under a business-as-usual development path, while countries with a high HDI value (>0.8) have to restrain their emissions to ensure that the global temperature rise does not exceed 2°C. For comparison, the well-known multi-regional RICE model is used to assess GDP growth under the same climate change policy goals.

Policy relevance

This is the first study that shifts the narrative of climate policy evaluation from one of GDP growth to a message of improving social welfare, as captured by the HDI. This could make it easier for political leaders and climate negotiators to publicly commit themselves to ambitious carbon emission reduction goals, such as limiting global warming to 2°C, as in the (non-binding) agreement made at COP 21 in Paris in 2015. We find that if impacts are framed in terms of growth in HDI per t CO2 emission per capita instead of in GDP, the HDI of poor countries and their emissions are allowed to increase under a business-as-usual development path, whereas countries with a high HDI (>0.8) must control emissions so that global temperature rise remains within 2°C. Importantly, a climate agreement is more attractive for rich countries under the HDI than the GDP frame. This is good news, as these countries have to make the major contribution to emissions reductions.  相似文献   

16.
Global exposure to river and coastal flooding: Long term trends and changes   总被引:1,自引:0,他引:1  
Flood damage modelling has traditionally been limited to the local, regional or national scale. Recent flood events, population growth and climate change concerns have increased the need for global methods with both spatial and temporal dynamics. This paper presents a first estimation of global economic exposure to both river and coastal flooding for the period 1970–2050, using two different methods for damage assessment. One method is based on population and the second is based on land-use within areas subject to 1/100 year flood events. On the basis of population density and GDP per capita, we estimate a total global exposure to river and coastal flooding of 46 trillion USD in 2010. By 2050, these numbers are projected to increase to 158 trillion USD. Using a land-use based assessment, we estimated a total flood exposure of 27 trillion USD in 2010. For 2050 we simulate a total exposure of 80 trillion USD. The largest absolute exposure changes between 1970 and 2050 are simulated in North America and Asia. In relative terms we project the largest increases in North Africa and Sub-Saharan Africa. The models also show systematically larger growth in the population living within hazard zones compared to total population growth. While the methods unveil similar overall trends in flood exposure, there are significant differences in the estimates and geographical distribution. These differences result from inherent model characteristics and the varying relationship between population density and the total urban area in the regions of analysis. We propose further research on the modelling of inundation characteristics and flood protection standards, which can complement the methodologies presented in this paper to enable the development of a global flood risk framework.  相似文献   
17.
While carbon pricing is widely seen as a crucial element of climate policy and has been implemented in many countries, it also has met with strong resistance. We provide a comprehensive overview of public perceptions of the fairness of carbon pricing and how these affect policy acceptability. To this end, we review evidence from empirical studies on how individuals judge personal, distributional and procedural aspects of carbon taxes and cap-and-trade. In addition, we examine preferences for particular redistributive and other uses of revenues generated by carbon pricing and their role in instrument acceptability. Our results indicate a high concern over distributional effects, particularly in relation to policy impacts on poor people, in turn reducing policy acceptability. In addition, people show little trust in the capacities of governments to put the revenues of carbon pricing to good use. Somewhat surprisingly, most studies do not indicate clear public preferences for using revenues to ensure fairer policy outcomes, notably by reducing its regressive effects. Instead, many people prefer using revenues for ‘environmental projects’ of various kinds. We end by providing recommendations for improving public acceptability of carbon pricing. One suggestion to increase policy acceptability is combining the redistribution of revenue to vulnerable groups with the funding for environmental projects, such as on renewable energy.

Key policy insights

  • If people perceive carbon pricing instruments as fair, this increases policy acceptability and support.

  • People’s satisfaction with information provided by the government about the policy instrument increases acceptability.

  • While people express high concern over uneven distribution of the policy burden, they often prefer using carbon pricing revenues for environmental projects instead of compensation for inequitable outcomes.

  • Recent studies find that people’s preferences shift to using revenues for making policy fairer if they better understand the functioning of carbon pricing, notably that relatively high prices of CO2-intensive goods and services reduce their consumption.

  • Combining the redistribution of revenue to support both vulnerable groups and environmental projects, such as on renewable energy, seems to most increase policy acceptability.

  相似文献   
18.
Australian climate-proxy reconstructions based on tree rings from tropical and subtropical forests have not been achieved so far due to the rarity of species producing anatomically distinct annual growth rings. Our study identifies the Australian Red Cedar (Toona ciliata) as one of the most promising tree species for tree-ring research in Australasia because this species exhibits distinct annual tree rings, a prerequisite for high quality tropical dendroclimatology. Based on these preliminary studies, we were able, for the first time in subtropical and tropical Australia, to develop a statistically robust, precisely dated and annually resolved chronology back to AD1854. We show that the variability in ring widths of T. ciliata is mainly dependent on annual precipitation. The developed proxy data series contains both high- and low-frequency climate signals which can be associated with the El Niño Southern Oscillation (ENSO) and the Interdecadal Pacific Oscillation (IPO). A comparison of different data sets (Brisbane precipitation, tree rings, coral luminescence record from the Great Barrier Reef, ENSO and IPO) revealed non-stationary correlation patterns throughout the twentieth century but little instability between the new tree-ring chronology and Brisbane precipitation.  相似文献   
19.
In the eastern Mediterranean in general and in Turkey in particular, temperature reconstructions based on tree rings have not been achieved so far. Furthermore, centennial-long chronologies of stable isotopes are generally also missing. Recent studies have identified the tree species Juniperus excelsa as one of the most promising tree species in Turkey for developing long climate sensitive stable carbon isotope chronologies because this species is long-living and thus has the ability to capture low-frequency climate signals. We were able to develop a statistically robust, precisely dated and annually resolved chronology back to AD 1125. We proved that variability of δ13C in tree rings of J. excelsa is mainly dependent on winter-to-spring temperatures (January–May). Low-frequency trends, which were associated with the medieval warm period and the little ice age, were identified in the winter-to-spring temperature reconstruction, however, the twentieth century warming trend found elsewhere could not be identified in our proxy record, nor was it found in the corresponding meteorological data used for our study. Comparisons with other northern-hemispherical proxy data showed that similar low-frequency signals are present until the beginning of the twentieth century when the other proxies derived from further north indicate a significant warming while the winter-to-spring temperature proxy from SW-Turkey does not. Correlation analyses including our temperature reconstruction and seven well-known climate indices suggest that various atmospheric oscillation patterns are capable of influencing the temperature variations in SW-Turkey.  相似文献   
20.
Over the past few decades Integrated Assessment (IA) has emerged as an approach to link knowledge and action in a way that is suitable to accommodate uncertainties, complexities and value diversities of global environmental risks. Responding to the complex nature of the climate problem and to the changing role of climate change in the international climate policy process, the scientific community has started to include stakeholder knowledge and perspectives in their assessments. Participatory Integrated Assessment (PIA) is in its early stage of development. Methodology varies strongly across PIA projects. This paper analyzes four recent IA projects of climate change that included knowledge or perspectives from stakeholders in one-way or another. Approaches and methods used turn out to differ in whether stakeholders are involved actively or passively, whether the approach is bottom-up or top-down, and whether the different functions in the IA process are open or closed to stakeholder input. Also, differences can be seen in the degree to which boundaries are pre-set that limit the roles and domains of competencies attributed to each scientific or non-scientific participant (so-called boundary work). The paper discusses pros and cons of the various approaches identified, and outlines heuristics and considerations to assist those who plan, design or fund new IA processes with stakeholder input on what approaches best to choose in view of the objectives for stakeholder involvement, in view of the role that the IA plays in the overall risk management process and in view of considerations regarding boundary work.  相似文献   
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