全文获取类型
收费全文 | 813篇 |
免费 | 16篇 |
国内免费 | 159篇 |
专业分类
安全科学 | 44篇 |
废物处理 | 30篇 |
环保管理 | 160篇 |
综合类 | 377篇 |
基础理论 | 153篇 |
环境理论 | 1篇 |
污染及防治 | 144篇 |
评价与监测 | 39篇 |
社会与环境 | 40篇 |
出版年
2024年 | 3篇 |
2023年 | 21篇 |
2022年 | 31篇 |
2021年 | 15篇 |
2020年 | 16篇 |
2019年 | 28篇 |
2018年 | 20篇 |
2017年 | 31篇 |
2016年 | 43篇 |
2015年 | 53篇 |
2014年 | 53篇 |
2013年 | 52篇 |
2012年 | 32篇 |
2011年 | 103篇 |
2010年 | 44篇 |
2009年 | 75篇 |
2008年 | 69篇 |
2007年 | 76篇 |
2006年 | 31篇 |
2005年 | 30篇 |
2004年 | 20篇 |
2003年 | 19篇 |
2002年 | 13篇 |
2001年 | 18篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 15篇 |
1997年 | 13篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1978年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有988条查询结果,搜索用时 15 毫秒
291.
Ecologists are increasingly actively involved in conservation. We identify five key topics from a broad sweep of ecology that merit research attention to meet conservation needs. We examine questions from landscape ecology, behavioral ecology, ecosystem dynamics, community ecology, and nutrient cycling related to key topics. Based on literature review and publication trend assessment, consultation with colleagues, and roundtable discussions at the 24th International Congress for Conservation Biology, focused research on the following topics could benefit conservation while advancing ecological understanding: 1. Carbon sequestration, requiring increased linkages to biodiversity conservation; 2. Ecological invasiveness, challenging our ability to find solutions to ecological aliens; 3. Individual variation, having applications in the conservation of rare species; 4. Movement of organisms, integrating ecological processes across landscapes and scales and addressing habitat fragmentation; and 5. Trophic-level interactions, driving ecological dynamics at the ecosystem-level. Addressing these will require cross-disciplinary research under the overarching framework of conservation ecology. 相似文献
292.
293.
Global warming can be curbed by pricing carbon emissions and thus substituting fossil fuel with renewable energy consumption. Breakthrough technologies (e.g., fusion energy) can reduce the cost of such policies. However, the chance of such a technology coming to market depends on investment. We model breakthroughs as an irreversible tipping point in a multi-country world, with different degrees of international cooperation. We show that international spill-over effects of R&D in carbon-free technologies lead to double free-riding, strategic over-pollution and underinvestment in green R&D, thus making climate change mitigation more difficult. We also show how the demand structure determines whether carbon pricing and R&D policies are substitutes or complements. 相似文献
294.
Carbon leakage is of interest in both academic and policy debates about the effectiveness of unilateral climate policy, especially in Europe, where the EU Emissions Trading System (EU ETS) affects many traded sectors. We review how the literature identifies leakage and the pollution haven effect. We then evaluate whether EU ETS emission costs caused carbon leakage in European manufacturing, using trade flows in embodied carbon and value from the Global Trade Analysis Project (GTAP). We find no evidence that the EU ETS caused carbon leakage. 相似文献
295.
I develop a differential game between an oil cartel and an importer investing in research and development (R&D) to reduce the cost of a green substitute to oil. In equilibrium, the cartel is forced to deter the substitute, which thus imposes a price ceiling falling over time. Credible carbon taxes are below the Pigovian level, implying the importer cannot internalise the full pollution externality, much less capture resource rents. Without carbon pricing, the importer curtails long-run pollution using a costly R&D programme. Normatively, climate policy will be more expensive if relying on green R&D programmes only. 相似文献
296.
Analysis of leakage in carbon sequestration projects in forestry: a case study of upper magat watershed,Philippines 总被引:2,自引:0,他引:2
Rodel D. Lasco Florencia B. Pulhin Renezita F. Sales 《Mitigation and Adaptation Strategies for Global Change》2007,12(6):1189-1211
The role of forestry projects in carbon conservation and sequestration is receiving much attention because of their role in
the mitigation of climate change. The main objective of the study is to analyze the potential of the Upper Magat Watershed
for a carbon sequestration project.
The three main development components of the project are forest conservation: tree plantations, and agroforestry farm development.
At Year 30, the watershed can attain a net carbon benefit of 19.5 M tC at a cost of US$ 34.5 M.
The potential leakage of the project is estimated using historical experience in technology adoption in watershed areas in
the Philippines and a high adoption rate. Two leakage scenarios were used: baseline and project leakage scenarios. Most of
the leakage occurs in the first 10 years of the project as displacement of livelihood occurs during this time. The carbon
lost via leakage is estimated to be 3.7 M tC in the historical adoption scenario, and 8.1 M tC under the enhanced adoption
scenario. 相似文献
297.
Development of regional climate mitigation baseline for a dominant agro-ecological zone of Karnataka,India 总被引:1,自引:0,他引:1
P. Sudha D. Subhashree H. Khan G. T. Hedge I. K. Murthy V. Shreedhara N. H. Ravindranath 《Mitigation and Adaptation Strategies for Global Change》2007,12(6):1051-1075
Setting a baseline for carbon stock changes in forest and land use sector mitigation projects is an essential step for assessing
additionality of the project. There are two approaches for setting baselines namely, project-specific and regional baseline.
This paper presents the methodology adopted for estimating the land available for mitigation, for developing a regional baseline,
transaction cost involved and a comparison of project-specific and regional baseline. The study showed that it is possible
to estimate the potential land and its suitability for afforestation and reforestation mitigation projects, using existing
maps and data, in the dry zone of Karnataka, southern India. The study adopted a three-step approach for developing a regional
baseline, namely: (i) identification of likely baseline options for land use, (ii) estimation of baseline rates of land-use
change, and (iii) quantification of baseline carbon profile over time. The analysis showed that carbon stock estimates made
for wastelands and fallow lands for project-specific as well as the regional baseline are comparable. The ratio of wasteland
Carbon stocks of a project to regional baseline is 1.02, and that of fallow lands in the project to regional baseline is 0.97.
The cost of conducting field studies for determination of regional baseline is about a quarter of the cost of developing a
project-specific baseline on a per hectare basis. The study has shown the reliability, feasibility and cost-effectiveness
of adopting regional baseline for forestry sector mitigation projects.
相似文献
N. H. RavindranathEmail: |
298.
Optimizing carbon sequestration in commercial forests by integrating carbon management objectives in wood supply modeling 总被引:2,自引:0,他引:2
Charles P.-A. Bourque Eric T. Neilson Chris Gruenwald Samantha F. Perrin Jason C. Hiltz Yvon A. Blin Geoffrey V. Horsman Matthew S. Parker Christie B. Thorburn Michael M. Corey Fan-rui Meng D. Edwin Swift 《Mitigation and Adaptation Strategies for Global Change》2007,12(7):1253-1275
This paper provides a methodology for generating forest management plans, which explicitly maximize carbon (C) sequestration at the forest-landscape level. This paper takes advantage of concepts first presented in a paper
by Meng et al. (2003; Mitigation Adaptation Strategies Global Change 8:371–403) by integrating C-sequestration objective functions in existing
wood supply models. Carbon-stock calculations performed in WoodstockTM (RemSoft Inc.) are based on C yields generated from volume table data obtained from local Forest Development Survey plots
and a series of wood volume-to-C content conversion factors specified in von Mirbach (2000). The approach is used to investigate the impact of three demonstration forest-management scenarios on the C budget in a
110,000 ha forest in south-central New Brunswick, Canada. Explicit demonstration scenarios addressed include (1) maximizing
timber extraction either by clearcut or selection harvesting for greatest revenue generation, (2) maximizing total C storage
in the forest landscape and in wood products generated from harvesting, and (3) maximizing C storage together with revenue
generation. The level of clearcut harvesting was greatest for scenario 1 (≥15 × 104 m3 of wood and ≥943 ha of land per harvesting period), and least for scenario 2 (=0 m3 per harvesting period) where selection harvesting dominated. Because softwood saw logs were worth more than pulpwood ($60 m−3 vs. $40 m−3) and were strategic to the long-term storage of C, the production of softwood saw logs exceeded the production of pulpwood
in all scenarios. Selection harvesting was generally the preferred harvesting method across scenarios. Only in scenario 1 did levels of clearcut harvesting occasionally exceed those of selection harvesting, mainly in the removal of old, dilapidated
stands early in the simulation (i.e., during periods 1 through 3). Scenario 2 provided the greatest total C-storage increase over 80 years (i.e., 14 × 106 Mg C, or roughly 264 Mg ha−1) at a cost of $111 per Mg C due to lost revenues. Scenarios 3 and 1 produced reduced storage rates of roughly 9 × 106 Mg C and 3 × 106 Mg C, respectively; about 64% and 22% of the total, 80-year C storage calculated in scenario 2. The bulk of the C in scenario 2 was stored in the forest, amounting to about 76% of the total C sequestered. 相似文献
299.
300.
N. Heydari 《International Journal of Green Energy》2019,16(6):476-482
A carbon/CoFe2O4 composite was synthesized by precipitation method. The morphology of the composite was analyzed using scanning electron microscopy, X-ray diffraction, transmission electron microscopy, Fourier Transform Infrared Spectra, and vibrating sample magnetometry. The electrocapacitive behaviors of the composite has been studies by cycle voltammogram and galvanic charge/discharge. The size of the nanoparticles carbon composite of CoFe2O4 was uniform and 209 nm. Due to a high percent of carbon, electrochemical measurements showed electrical double layer mechanism. Specifically, the carbon/cobalt ferrite electrode exhibited high specific capacitance of 102.5 F g?1 at a current density of 0.16 A g?1, and high rate capability with 30% retention of capacitance even up to 20 A g?1, and excellent cycling stability with 81.5% retention of the initial capacitance after 6000 charge/discharge cycles, supporting that the carbon cobalt ferrite composite electrode could be a potential candidate for supercapacitor application. 相似文献