全文获取类型
收费全文 | 2235篇 |
免费 | 128篇 |
国内免费 | 387篇 |
专业分类
安全科学 | 124篇 |
废物处理 | 18篇 |
环保管理 | 313篇 |
综合类 | 1218篇 |
基础理论 | 270篇 |
环境理论 | 6篇 |
污染及防治 | 102篇 |
评价与监测 | 98篇 |
社会与环境 | 341篇 |
灾害及防治 | 260篇 |
出版年
2024年 | 5篇 |
2023年 | 36篇 |
2022年 | 65篇 |
2021年 | 98篇 |
2020年 | 85篇 |
2019年 | 99篇 |
2018年 | 88篇 |
2017年 | 97篇 |
2016年 | 97篇 |
2015年 | 69篇 |
2014年 | 101篇 |
2013年 | 164篇 |
2012年 | 158篇 |
2011年 | 163篇 |
2010年 | 92篇 |
2009年 | 103篇 |
2008年 | 116篇 |
2007年 | 139篇 |
2006年 | 120篇 |
2005年 | 114篇 |
2004年 | 101篇 |
2003年 | 81篇 |
2002年 | 76篇 |
2001年 | 86篇 |
2000年 | 82篇 |
1999年 | 64篇 |
1998年 | 45篇 |
1997年 | 37篇 |
1996年 | 35篇 |
1995年 | 34篇 |
1994年 | 27篇 |
1993年 | 16篇 |
1992年 | 18篇 |
1991年 | 13篇 |
1990年 | 12篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有2750条查询结果,搜索用时 312 毫秒
851.
中国城市温室气体排放清单编制和方法概述 总被引:5,自引:0,他引:5
介绍中国国家层面的温室气体排放清单编制现状,概述了中国城市层面温室气体排放清单研究进展,总结国际通用的城市清单方法(Urban Inventory Methods),包括以排放为中心的IPCC和WRI/WBCSD温室气体排放模型、以需求为中心的混合生命周期方法和中国现状城市温室气体排放清单编制方法,阐述在目前的城市温室... 相似文献
852.
853.
In this paper, a real options based binominal lattices model for the investment of coal bed methane (CBM) is conducted. CBM prices and market demand are incorporated into the model as the predominant uncertain factors and it is solved by using the bidimensional binominal lattices approach. Then the model is employed to evaluate the investment in CBM projects in China, and the effect of related policies is analyzed. The empirical results demonstrate that the model can be used to offer a better explanation of why the CBM industry has developed slowly in China from an investment perspective. It is found that the current policy environment is not positive enough to attract investment in the CBM industry. Among various factors, CBM prices yield the most significant effect on stimulating investment in CBM development. Increasing the price subsidy is also an effective policy to stimulate investment and promote the development of the CBM industry in China. 相似文献
854.
China is the second largest emitter of greenhouse gases (GHG) in the world, with potentially about two thirds of total Certified Emission Reductions (CERs) for Asia on the world carbon market (). Since 68% of its primary energy is from coal, China's average energy intensity is 7.5 times higher than the EU and 4.3 times higher than the US (EU, 2003). Therefore, introducing advanced clean technologies and management to China represents opportunities for Annex I countries to obtain low-cost CERs through CDM projects, and access to one of the largest potential energy conservation markets in the world. CDM can provide a win-win solution for both China and Annex I countries, and the Chinese government considers that the introduction of CDM projects can bring advanced energy technologies and foreign investment to China, thereby helping China's sustainable economy and generating CERs. As energy efficiency is generally low and carbon intensity is high in both China's energy supply and demand sectors, numerous options exist for cost-effective energy conservation and GHG mitigation with CDM. This paper reviews current Chinese policies and administrative and institutional settings for CDM cooperation, and discusses existing policy, institutional and other barriers in the energy market by drawing on observations and experience from previous initiatives such as Cleaner Production and energy efficiency. Some options to remove these barriers are addressed. In order to make CDM projects feasible, China's government needs to promote awareness, streamline administrative systems, and be more active in building a competitive edge in the world carbon market. 相似文献
855.
Biogeochemistry of Chinese estuarine and coastal waters: nutrients, trace metals and biomarkers 总被引:5,自引:0,他引:5
Jing Zhang 《Regional Environmental Change》2002,3(1-3):65-76
The dissolved and particulate trace metals in large and middle-sized Chinese rivers remain comparable with other less-disturbed
world systems. Levels of nutrients in Chinese rivers are high due to erosion over the drainage area and the application of
chemical fertilizers, which induces an N/P ratio up to 100–1,000. The concentrations of organic pollutants in Chinese rivers
are ranked at the lower end of those of world systems; however, pollution has been identified in coastal waters from north
to south of the country. In estuarine and coastal waters, dissolved trace metals illustrate a feature of remobilization, while
non-conservative distribution is observed, with exceptions for iron and aluminum. Particulate trace metals demonstrate a fairly
stable distribution along the salinity gradient, when the absolute concentration is normalized to reference materials. In
high-turbidity estuaries, seaward nutrient flux can be increased by a factor of 5–10. Finally, the N/P ratio approaches 10–20
at the interior of the East China Sea, indicating that in coastal regions photosynthesis changes from P to N and Si limitations.
Electronic Publication 相似文献
856.
Inrecentseveralyears ,abnormaldroughtoccursinthepartnorthernofChina .Itex ertssomeinfluenceonChina’snationaleconomyandhasarousedwideattentionfromallwalksoflife .Muchresearchindrought wetindexhasbeendonebothathomeandabroad .Theresultcanbeclassifiedintotwocategories:first,droughtindexdirectlyisdefinedbyprecipitationorothermeteorologicalfactors;second ,droughtindexisidentifiedbycalculatinggainingandlos ingoflocalwaterinaccordancewithequationofwaterbalance ,andsomealsoconsidertheim pactofdrought… 相似文献
857.
循环经济理论及其在中国实践研究 总被引:39,自引:0,他引:39
循环经济理论在国际上尚处于探索与发展过程的过程中,本文运用系统科学和实证研究的方法,对我国循环经济理论与实践问题进行了初步分析。 相似文献
858.
人类社会的城市化进程始终是与对水资源的开发利用同步的 ,水资源短缺将是制约城市发展的一道门槛。然而 ,在我国西部地区存在着严重的水资源短缺和难以利用的情况 ,无序的城市化又进一步恶化了本已极为严峻的水资源短缺。但城市化始终是实现西部开发的必然选择。因此 ,在实现西部大开发战略 ,推进城市化进程的过程中 ,必须通过严格控制中心城市规模 ,以控制对水资源的局部过度需求 ;通过进一步优化城镇体系布局 ,在推进城市化进程的同时 ,实现区域范围内水资源的供需平衡 ;通过对现有的城市产业结构加以调整 ,以提高水资源的利用效率。只有依靠这种适宜的城市化战略 ,才能在城市化进程中跨越水资源门槛 ,最终实现西部地区的可持续发展 相似文献
859.
论我国农业可持续发展的环境与出路 总被引:1,自引:0,他引:1
从现在起到21世纪,农业担负着支撑国民经济快速发展的历史使命,完成一使命的唯一途径是确保农业的持续发展。作者在深入分析现阶段我国农业所面临的许多不利环境因素的基础上,提出了培育农业持续发展条件,优化农业持续发展环境的可行对策。 相似文献
860.