全文获取类型
收费全文 | 108篇 |
免费 | 6篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 11篇 |
废物处理 | 6篇 |
环保管理 | 20篇 |
综合类 | 42篇 |
基础理论 | 19篇 |
污染及防治 | 5篇 |
评价与监测 | 4篇 |
社会与环境 | 14篇 |
灾害及防治 | 2篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2010年 | 8篇 |
2009年 | 7篇 |
2008年 | 7篇 |
2007年 | 14篇 |
2006年 | 9篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1988年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有123条查询结果,搜索用时 31 毫秒
41.
42.
Simon Hakim 《Journal of the American Water Resources Association》1981,17(6):987-993
ABSTRACT: This paper suggests theoretical models to forecast the demand for recreational boats in a metropolitan area, and their expected usage in various regional water bodies and marinas. The models, which are similar to those used in transportation studies, are implemented using statistical regression analysis and can be easily applied to a wide range of case studies. The models have been used to forecast demand for boats by type and size in the Cleveland S.M.S.A. The proportion of boats attracted to boating facilities on Lake Erie has been calculated. This study is significant in suggesting a theoretically sound methodology to project facilities required for recreational boats. 相似文献
43.
综合整治府南河走可持续发展之路 总被引:2,自引:1,他引:1
府南河工程带动成都市城市基础设施建设,产生了巨大 在的社会效益,促进了环境保护及城市生态的良性循环,造就了成都市建设现代化商贸中心的前提条件,为成都市的可持续发展奠定了基础。 相似文献
44.
In this paper, a mathematical model is developed for net methane emission from rice fields by coupling methane production
model with methane oxidation model. Several dynamical regimes were formed through qualitative analysis of the model, and corresponding
dynamic features were interpreted through emission indices. Sensitivity of the model is discussed under the effects of temperature
and oxygen concentration in methanogenic and methane oxidation phases, respectively, and interpreted by defining an index;
in addition, control parameters are identified and their threshold limits defined. The out-busting emission tendency of methane
is considered separately and a forcing strategy was defined to force emission level towards zero in the long term. Lastly,
a complete control strategy is proposed for reducing methane emission. 相似文献
45.
从火电厂加强水务管理和废污水治理的角度,对生活污水、含油污水、灰水、循环水的治理现状和措施作了较全面地介绍,初步分折了火电厂节水的经济效益,并介绍了实际工程设计中的一些体会。 相似文献
46.
针对某企业150 t转炉二次除尘系统烟气捕集效果不佳、布袋除尘器压差大、运行能耗高等问题进行了系统诊断,利用排查系统管网、实测压力和流量、分析风机特性等手段,找出了问题原因并提出改进措施。通过实施改进措施,优化了150 t转炉二次除尘系统的运行方式,确保二次除尘效果并实现节能、经济运行。 相似文献
47.
48.
49.
Most models of habitat selection assume that individual animals choose and either reuse or abandon sites based on a constant
reassessment of site quality. When survival is a function of the presence of conspecifics, however, the benefits of returning
to traditional sites may override resource assessment. Many animals form roosting aggregations at what appear to be traditional
sites. At our study site in Nicaragua, the harvestman Prionostemma sp. forms diurnal roosting aggregations on a small subset of the available spiny palm trees. With respect to physical characteristics
and microclimate, the spiny palms used by the harvestmen resembled a random sample of those available, yet the same subset
of trees was used in two different years (2001, 2003). This suggests that the location of aggregation sites is traditional,
not a product of habitat limitation. Individual harvestmen were not faithful to particular roost sites, however, which raises
the question of how the tradition could be maintained over time. In this paper, we present evidence, derived from a series
of small-scale field experiments, that the harvestmen mark roosting sites chemically and enter marked sites preferentially
when searching for places to roost. We also show that the harvestmen are sensitive to changes in site quality (the presence
of spines) but will continue to use degraded traditional sites when no intact spiny palms are nearby. This system provides
an example of how animal traditions could be maintained over multiple generations without learning. Site-labeling can be viewed
as an external form of social memory. 相似文献
50.
我国民族村寨旅游景观系统的构建缺乏理论研究,结合景观生态学相关理论对民族村寨旅游景观系统的构建提出初步构想,并对该系统的结构、特性等进行了分析。 相似文献