全文获取类型
收费全文 | 9266篇 |
免费 | 519篇 |
国内免费 | 2085篇 |
专业分类
安全科学 | 582篇 |
废物处理 | 474篇 |
环保管理 | 750篇 |
综合类 | 4274篇 |
基础理论 | 1714篇 |
环境理论 | 3篇 |
污染及防治 | 2568篇 |
评价与监测 | 605篇 |
社会与环境 | 692篇 |
灾害及防治 | 208篇 |
出版年
2024年 | 31篇 |
2023年 | 149篇 |
2022年 | 440篇 |
2021年 | 395篇 |
2020年 | 379篇 |
2019年 | 322篇 |
2018年 | 392篇 |
2017年 | 387篇 |
2016年 | 406篇 |
2015年 | 465篇 |
2014年 | 550篇 |
2013年 | 808篇 |
2012年 | 583篇 |
2011年 | 645篇 |
2010年 | 528篇 |
2009年 | 527篇 |
2008年 | 573篇 |
2007年 | 483篇 |
2006年 | 462篇 |
2005年 | 330篇 |
2004年 | 319篇 |
2003年 | 333篇 |
2002年 | 300篇 |
2001年 | 388篇 |
2000年 | 306篇 |
1999年 | 173篇 |
1998年 | 147篇 |
1997年 | 127篇 |
1996年 | 104篇 |
1995年 | 88篇 |
1994年 | 92篇 |
1993年 | 86篇 |
1992年 | 67篇 |
1991年 | 55篇 |
1990年 | 45篇 |
1989年 | 44篇 |
1988年 | 33篇 |
1987年 | 17篇 |
1986年 | 26篇 |
1985年 | 16篇 |
1984年 | 23篇 |
1983年 | 24篇 |
1982年 | 30篇 |
1981年 | 18篇 |
1980年 | 11篇 |
1979年 | 14篇 |
1978年 | 18篇 |
1975年 | 13篇 |
1973年 | 10篇 |
1972年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 304 毫秒
1.
Huang Ying Jiang Qiongji Yu Xubiao Gan Huihui Zhu Xia Fan Siyi Su Yan Xu Zhirui He Cunrui 《Environmental science and pollution research international》2021,28(37):51251-51264
Environmental Science and Pollution Research - Trace copper ion (Cu(II)) in water and wastewater can trigger peroxymonosulfate (PMS) activation to oxidize organic compounds, but it only works under... 相似文献
2.
Baek Kitae Alessi Daniel S. Man Yu Bon Kwon Eilhann E. 《Environmental geochemistry and health》2021,43(9):3261-3262
Environmental Geochemistry and Health - 相似文献
3.
Chengyuan Gong Yi Yu Kaiqiang Wang Zhengkai Tu 《International Journal of Green Energy》2020,17(10):591-601
ABSTRACT In this study, a three-dimension (3D) computational model was proposed to investigate the flow and heat transfer characteristics of the intake grilles of two different fuel cell vehicles. The models of the intake grilles were constructed according to the actual sizes of two vehicles, namely, Roewe 950 and Toyota Mirai, considering the heat dissipation unit to simplify the heat transfer model of the vehicle. The results showed that relative to Roewe 950, Mirai intake air flow rate was approximately 10% higher, the heat transfer capacity was approximately 7% higher, and the intake grille area was larger. The coolant outlet temperature of Mirai was lower than that of Roewe 950, which was beneficial for the long term and stable operation of a fuel cell. This comparative study provided guidance for the intake grille and radiator design of fuel cell vehicles. The only difference between fuel cell vehicles on the market and conventional vehicles was that in the former, the internal combustion engine was replaced with a fuel cell stack, which had insufficient heat transfer capacity because of the reducing temperature difference. Increasing the intake grille area and the heat exchange capacity of the radiator were the key issues for the development of fuel cell vehicles. In this study, an optimal window opening angle of the radiator fin of 23° provided a maximal heat transfer coefficient. 相似文献
4.
M. Kansanga P. Andersen D. Kpienbaareh S. Mason-Renton K. Atuoye Y. Sano 《国际发展与全球生态学杂志》2019,26(1):11-24
Following the renewed effort at achieving a new green revolution for Africa, emphasis has been placed on modernizing smallholder agriculture through the deployment of improved inputs especially mechanized technologies. In Ghana, the government has in the last decade emphasized the provision of subsidized mechanized ploughing services to farmers alongside a rapidly growing private sector tractor service market. While mechanized technology adoption rates have increased rapidly, the deployment of these technologies has been without critical analysis of the impacts on production patterns and local agrarian systems. This paper examines the distributional impacts of agriculture mechanization on cropping patterns and farm sizes of smallholder farmers in northern Ghana using Geographic Information Systems (GIS) techniques, and semi-structured interviews with smallholder farmers (n=60). Specifically, comparative analysis of the field sizes and cropping patterns of participant farmers prior to and after the adoption of mechanized technologies was conducted. In-depth interviews were used to contextualize the experiences of smallholder farmers toward understanding how mechanization may be impacting traditional agriculture. Our findings reveal a mechanization paradox in which farm sizes are expanding, while cropping patterns are shifting away from traditional staple crops (pearl millet and sorghum bicolor) to market-oriented crops (maize, rice and groundnuts). This transition we argue, has adverse implications on the cultural dimension of food security, the organization of social life, and climate change adaptation. We recommend a retooling of the current agricultural policy focus to ensure context sensitivity for a more robust battle against food insecurity. 相似文献
5.
为探究我国重特大安全生产事故特征,选取2005-2019年国内852起重特大事故作为研究对象,基于Python编程语言针对重特大事故发生的年份、季度、月份、工作日与非工作日、地域特征进行分析.结果表明:2005-2019年,国内重特大安全生产事故起数和死亡人数均在不断下降;第四季度发生重特大事故最多,而第三季度平均每起事故造成的死亡人数最多;重特大事故数量和死亡人数随月份显示出反复波动的趋势,均呈现3个"^",形;工作日期间发生的重特大事故数量最多,非工作日平均事故率最大;国庆节是重特大事故发生最多的节假日;贵州、湖南、山西、云南、河南等省份"十四五"期间需要重点加强安全和应急管理. 相似文献
6.
7.
8.
9.
工业革命以来,全球环境发生了前所未有的变化,将可能给地球系统带来灾难性后果,究其原因主要是由于人类活动造成的。人的行为深受意识的影响和制约,环境意识对于环境问题的产生和解决至关重要。本文选取上海、香港两个地区来分析公民对环境的关注度、公民的环保意识、环保行为以及公民对政府环境工作的看法和评价,研究公民对全球环境变化反应的区域差异,为政府制定相关环境保护政策提供理论依据。调查结果显示,上海、香港两地公民在很多环境闷题上具有共识。但是。在对手环境状况好转的期待值、参与环境保护活动的积极性、对人为因素主导力量的认识、环境保护与日常生活的切实关系、为环境保护的支付意愿、对于环境教育内容的认可度等方面存在着一定的差异。 相似文献
10.
Tanay B. Yıldırım Tutku Ak Zuhal Ölmez 《Environment, Development and Sustainability》2008,10(6):871-881
While the world is going into different tourism expectations, the tourism understanding in Turkey is defined as tourism in the sea-sand-sun triangle. However, it is possible to contribute to the income and local development of the indigenous people by developing nature-based tourism. Besides, with the sustainable use and preservation of the natural-cultural assets, the damage of the traditional tourism industry on the natural and cultural environment could be reduced. In this study, it is aimed to bring up the nature-based tourism concept in Çanakkale by evaluating the nature-based tourism industry in the general of Turkey and assessing the natural-cultural resources that Çanakkale comprehends. The most important areas that have a nature-based tourism potential in Çanakkale and the tourism activities that are most suitable for these areas have been determined. 相似文献