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651.
652.
Effects of Recreational Impacts on Soil Microbial Communities 总被引:51,自引:0,他引:51
/ The functional diversity of soil microbial communities in heavilyimpacted subalpine campsites and adjacent undisturbed areas was comparedusing the Biolog method of carbon utilization profiles. Principal componentsanalysis of patterns and level of microbial activity indicate that microbialcommunities differentiate in response to disturbance in the top 6 cm of soil,while below 6 cm there were no recognizable differences between disturbed andundisturbed soil communities. Analysis of the factors that differentiate theupper microbial communities between disturbed and undisturbed sites revealedthat the percent of total carbon sources utilized was significantly less inthe disturbed (54%) than in undisturbed areas (95%). Carbonsubstrates important in the discrimination between soil communities includeplant, invertebrate, and microbial derivatives that could not be metabolizedby microbial communities from disturbed sites. Comparisons of totalculturable actinomycetes, bacteria, and fungi reveal no difference in overallnumber of colony forming units (CFU) on disturbed and undisturbed sites, buta marked decrease in actinomycetes on disturbed sites. Biolog andspread-plate data combined indicate a shift in the structure and function ofthe microbial community in campsite soils, which may be a useful indicator ofsoil community disturbance.KEY WORDS: Microbial functional diversity; Anthropogenic disturbance;Recreational impacts; Carbon source profile; Subalpine 相似文献
653.
Carbon sequestration,biological diversity,and sustainable development: Integrated forest management 总被引:2,自引:0,他引:2
Tropical deforestation provides a significant contribution to anthropogenic increases in atmospheric CO2 concentration that may lead to global warming. Forestation and other forest management options to sequester CO2 in the tropical latitudes may fail unless they address local economic, social, environmental, and political needs of people
in the developing world. Forest management is discussed in terms of three objectives: carbon sequestration, sustainable development,
and biodiversity conservation. An integrated forest management strategy of land-use planning is proposed to achieve these
objectives and is centered around: preservation of primary forest, intensified use of nontimber resources, agroforestry, and
selective use of plantation forestry.
The information in this document has been wholly funded by the US Environmental Protection Agency. It has been subjected to
the agency's peer and administrative review and approved for publication of an EPA document. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use. 相似文献
654.
Land use change and carbon exchange in the tropics: III. Structure,basic equations,and sensitivity analysis of the model 总被引:1,自引:0,他引:1
The rationale, assumptions, structure and basic mathematical functions of the model used to produce the simulation results reported in the first two articles of this series are described in detail. Sensitivity analysis indicates that the most important parameters in the model, and, presumably, in the carbon exchange between tropical forests and the atmosphere, are: (a) the conversion rate of forests to permanent pasture and agriculture, (b) the changes that are occurring and have occurred in the shifting cultivation system, and (c) the fate of cleared vegetation. Although it is not possible to validate the model against direct measurements of carbon exchange, the model has been proven robust when subject to a series of explicit analyses and comparisons with other assessments. 相似文献
655.
Determining the effect of tropical land use on the carbon dioxide (CO2) content of the atmosphere requires: (a) estimates of the rates of land use change, (b) estimates of the difference between the carbon stored in forests and that stored in pastures and cultivated fields, and (c) a consideration of the fate of carbon stored in the cleared vegetation. The first article of this series analyzed land use in four tropical countries and estimated the carbon released to the atmosphere as a consequence of changes in land use. This article estimates the carbon released from the entire tropical region based on the two published studies of land use change for the tropics as a whole that distinguish between temporary and permanent land use: Seiler and Crutzen (1980) and Lanly (1982). We combine these estimates with two estimates of the difference in carbon storage between forests and fields derived from Whittaker and Likens (1975) and Brown and Lugo (1982), and the two scenarios of the fate of cleared vegetation, developed in the previous article, to produce several complete sets of data describing the necessary parameters to calculate carbon exchange. These data sets, entered into our model, produce a range of estimates of the annual release of carbon from tropical vegetation in 1980 of from 0.6 to 1.8 BMT/year, with the more likely range being 0.9–1.2 BMT/year. Our preliminary analysis suggests that the release from tropical soils due to land use change adds about an additional 0.3 BMT C/year, so that the total release is probably between 1.2 and 1.5 BMT C/year. Peng and others (1983) reported that new models of the oceanic carbon cycle can accommodate at least 1.2 BMT C/year in 1980 from forests and soils. Our results indicate that, given the uncertainties in the size of both the biotic release and oceanic uptake, the global carbon budget may be balanced if there is no significant release from nontropical ecosystems due to land use change and all mature ecosystems are in collective equilibrium with the atmosphere. 相似文献
656.
Akira Hoshino Maso Tsuji Masanori Momochi Akiko Mizutani Hideo Sawada Setsuo Kohnami Hiroki Nakagomi Michio Ito Hisato Saida Munehiro Ohnishi Michimasa Hirata Masao Kunioka Masahiro Funabash Shogo Uematsu 《Journal of Polymers and the Environment》2007,15(4):275-280
Several ISO standards for determining the ultimate aerobic/anaerobic biodegradability of plastic materials have been published.
In particular, ISO 14855-1 is a common test method that measures evolved carbon dioxide using such methods as continuous infrared
analysis, gas chromatography or titration and others (ISO 14855-1(2005.9)). This method is a small-scale test for determining
the ultimate aerobic biodegradability of plastic materials, where the amounts of compost inoculum and test sample in one tenth
comparing with that of ISO 14855-1. This method is well versed in ISO/DIS 14855-2 which the carbon dioxide evolved from test
vessel is determined by gravimetric analysis of carbon dioxide absorbent. The focus of this study is to elucidate statistically
the results of round robin test by seven countries used MODA, which were various deviations among the experiments. 相似文献
657.
成都市可持续发展测度与分析 总被引:1,自引:0,他引:1
生态足迹是一种定量测量人类对自然利用程度的方法,已经被广泛应用于定量测度区域或城市的可持续发展。成都地处我国西部,是西部大开发的战略高地和“桥头堡”,对西部地区的发展起着示范、先导、辐射和带动作用。采用生态足迹理论和计算模型对成都市各类土地面积进行量化,具体计算出成都市的生态承载力、供需结构。计算结果表明,2003年其人均生态足迹超过了它的人均生态承载力,生态经济系统存在生态赤字,必须采取措施提高生态承载力,减少生态压力,探讨可持续发展的道路。 相似文献
658.
Modification of ecological footprint evaluation method to include non-renewable resource consumption using thermodynamic approach 总被引:5,自引:0,他引:5
This study is to modify the ecological footprint methodology by incorporating non-renewable or abiotic resources as an additional category. The use of abiotic resources can be quantified as global hectare by using thermodynamic approaches. A detailed case study on various countries including Australia, Belgium, Brazil, Canada, Japan, USA, and Vietnam shows the advantage of using the new modified ecological footprint (EF) as an indicator for sustainable development. The modified EF includes not only biotic resources, but also the abiotic resources. The case study indicates that the modified EF differs from the traditional EF up to 123% in the case of Belgium, and 90% in the case of Australia. For developing countries such as Brazil and Vietnam, the differences are relatively smaller (21% for Brazil and 9.4% for Vietnam). The estimated total ecological footprint of the world using the new method implies more serious problems associated with over consumption than using results from the original ecological footprint method. 相似文献
659.
应用生态足迹计算模型和统计数据,对青岛市1998-2002年的生态足迹和生态承栽力进行了动态分析,并预测了未来青岛市的可持续发展趋势。 相似文献
660.
'People, planet and prosperity': The determinants of humanity's environmental footprint 总被引:1,自引:1,他引:1
Geoffrey P. Hammond 《Natural resources forum》2006,30(1):27-36
Environmental or ‘ecological’ footprints have been widely used in recent years as indicators of resource consumption and waste absorption on the basis of biologically productive land area required per capita with prevailing technology. Such footprints represent a partial measure of the extent to which the planet, its regions, or nations are moving along a sustainable development pathway. They vary between countries at different stages of economic development and varying geographic characteristics. The determinants of environmental footprints in some 113 countries from around the world have been evaluated. Dimensional analysis techniques from engineering and the physical sciences are employed to determine the relative significance of population density, economic wealth, and intensity of pollutant emission. Variations about the resulting ‘power‐law’ correlation suggest the extent to which individual nations are currently frugal or profligate in terms of their resource use and environmental impacts. The scatter associated with footprints, or closely related parameters, also indicates the uncertainty inherent within the international datasets needed to compute them, as well as differences in local climate and terrain. Nevertheless, national footprints alert humanity to the necessity of living within the regenerative capacity of the biosphere in order to ensure ‘environmental sustainability’. 相似文献