全文获取类型
收费全文 | 18174篇 |
免费 | 1350篇 |
国内免费 | 3925篇 |
专业分类
安全科学 | 2613篇 |
废物处理 | 188篇 |
环保管理 | 2436篇 |
综合类 | 10820篇 |
基础理论 | 2124篇 |
环境理论 | 11篇 |
污染及防治 | 1529篇 |
评价与监测 | 1068篇 |
社会与环境 | 1558篇 |
灾害及防治 | 1102篇 |
出版年
2024年 | 100篇 |
2023年 | 388篇 |
2022年 | 631篇 |
2021年 | 739篇 |
2020年 | 708篇 |
2019年 | 603篇 |
2018年 | 548篇 |
2017年 | 707篇 |
2016年 | 824篇 |
2015年 | 855篇 |
2014年 | 852篇 |
2013年 | 1057篇 |
2012年 | 1289篇 |
2011年 | 1389篇 |
2010年 | 1022篇 |
2009年 | 1007篇 |
2008年 | 805篇 |
2007年 | 1223篇 |
2006年 | 1223篇 |
2005年 | 968篇 |
2004年 | 808篇 |
2003年 | 916篇 |
2002年 | 736篇 |
2001年 | 608篇 |
2000年 | 560篇 |
1999年 | 535篇 |
1998年 | 409篇 |
1997年 | 325篇 |
1996年 | 271篇 |
1995年 | 253篇 |
1994年 | 243篇 |
1993年 | 200篇 |
1992年 | 156篇 |
1991年 | 120篇 |
1990年 | 81篇 |
1989年 | 49篇 |
1988年 | 43篇 |
1987年 | 19篇 |
1986年 | 21篇 |
1985年 | 29篇 |
1984年 | 16篇 |
1983年 | 17篇 |
1982年 | 13篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 12篇 |
1977年 | 11篇 |
1973年 | 9篇 |
1972年 | 5篇 |
1971年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
The inherent risks associated with accidental releases of hazardous materials during transport have drawn attention and concerns in the recent decades. The aim of this study is to propose a tool for evaluation and comparison of the transportation networks which can be used to assess the routing options between origins and destinations of the cargos for their suitability for transporting hazardous material cargos by tanker trucks and to identify routes which provide lower accidental release risks, lower public exposure risks, and offer economical benefits. Each route segment of transportation networks were evaluated using specific criteria which included health risk and cost of delay in case of an accidental release of materials, trucking cost and proximity to vulnerable areas. Since, the health impact of hazardous materials differ depending on the characteristics of the material being transported as well as release quantities and atmospheric conditions; this paper aimed in providing a tool that can be used to estimate the impact radius (for health risks) after accidental release of hazardous materials by taking into account different atmospheric conditions based on the meteorological data and solar elevation angle. The Gaussian air dispersion model paired with ArcGIS using Python programming were employed to estimate the health risk impact zones by considering the meteorological data, and accordingly to analyze road segments for cost impacts (delay and trucking costs), and the proximity to vulnerable areas. The route assessment tool was demonstrated with a case study. The results of this study can efficiently aid decision makers for transportation of hazardous materials. 相似文献
105.
Theoretical arguments for using a term structure of social discount rates (SDR) that declines with the time horizon have influenced government guidelines in the US and Europe. The certainty equivalent discount rate that often underpins this guidance embodies uncertainty in the primitives of the SDR, such as growth. For distant time horizons the probability distributions of these primitives are ambiguous and the certainty equivalent itself is uncertain. Yet, if a limited set of characteristics of the unknown probability distributions can be agreed upon, ‘sharp’ upper and lower bounds can be defined for the certainty-equivalent SDR. Unfortunately, even with considerable agreement on these features, these bounds are widely spread for horizons beyond 75 years. So while estimates of the present value of intergenerational impacts, including the social cost of carbon, can be bounded in the presence of this ambiguity, they typically remain so imprecise as to provide little practical guidance. 相似文献
106.
Plant conservation initiatives lag behind and receive considerably less funding than animal conservation projects. We explored a potential reason for this bias: a tendency among humans to neither notice nor value plants in the environment. Experimental research and surveys have demonstrated higher preference for, superior recall of, and better visual detection of animals compared with plants. This bias has been attributed to perceptual factors such as lack of motion by plants and the tendency of plants to visually blend together but also to cultural factors such as a greater focus on animals in formal biological education. In contrast, ethnographic research reveals that many social groups have strong bonds with plants, including nonhierarchical kinship relationships. We argue that plant blindness is common, but not inevitable. If immersed in a plant‐affiliated culture, the individual will experience language and practices that enhance capacity to detect, recall, and value plants, something less likely to occur in zoocentric societies. Therefore, conservation programs can contribute to reducing this bias. We considered strategies that might reduce this bias and encourage plant conservation behavior. Psychological research demonstrates that people are more likely to support conservation of species that have human‐like characteristics and that support for conservation can be increased by encouraging people to practice empathy and anthropomorphism of nonhuman species. We argue that support for plant conservation may be garnered through strategies that promote identification and empathy with plants. 相似文献
107.
Reem Hajjar Peter Cronkleton Emily Etue Peter Newton Aaron J.M. Russel Januarti Sinarra Tjajadi Wen Zhou Arun Agrawal 《Conservation biology》2016,30(6):1357-1362
Conservation and development practitioners increasingly promote community forestry as a way to conserve ecosystem services, consolidate resource rights, and reduce poverty. However, outcomes of community forestry have been mixed; many initiatives failed to achieve intended objectives. There is a rich literature on institutional arrangements of community forestry, but there has been little effort to examine the role of socioeconomic, market, and biophysical factors in shaping both land‐cover change dynamics and individual and collective livelihood outcomes. We systematically reviewed the peer‐reviewed literature on community forestry to examine and quantify existing knowledge gaps in the community‐forestry literature relative to these factors. In examining 697 cases of community forest management (CFM), extracted from 267 peer‐reviewed publications, we found 3 key trends that limit understanding of community forestry. First, we found substantial data gaps linking population dynamics, market forces, and biophysical characteristics to both environmental and livelihood outcomes. Second, most studies focused on environmental outcomes, and the majority of studies that assessed socioeconomic outcomes relied on qualitative data, making comparisons across cases difficult. Finally, there was a heavy bias toward studies on South Asian forests, indicating that the literature on community forestry may not be representative of decentralization policies and CFM globally. 相似文献
108.
2019年新冠疫情席卷全球,在疫情环境下,医疗废物大幅增多,全国各大城市纷纷出现医疗废物处置不当的现象。本文对国内外现状分析,在认知、设施、管理和监督四个方面发现存在一定的问题,通过加强教育、加大储备、完善机制和改善监管的建议,为提升医疗废物应急处置能力提供参考。 相似文献
109.
参照《纳氏试剂分光光度法》的方法原理,用分光光度计对3种光程长度比色皿分别进行比色,探讨不同光程长度比色皿间关系。 相似文献
110.
康乐 《辽宁城乡环境科技》2013,(5):33-35
评述了近年来城市污水生物脱氮除磷理论和功能微生物的研究进展,重点介绍了生物处理的新方法:短程硝化反硝化处理法、厌氧氨氧化处理法、同步硝化反硝化处理法、同步反硝化除磷脱氮法,并总结了各处理工艺的应用状况。对生物脱氮除磷微生物学和新的理论技术发展趋势做出了展望。 相似文献