首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2454篇
  免费   137篇
  国内免费   946篇
安全科学   159篇
废物处理   136篇
环保管理   203篇
综合类   1400篇
基础理论   439篇
污染及防治   901篇
评价与监测   114篇
社会与环境   95篇
灾害及防治   90篇
  2024年   2篇
  2023年   52篇
  2022年   148篇
  2021年   131篇
  2020年   91篇
  2019年   91篇
  2018年   100篇
  2017年   133篇
  2016年   114篇
  2015年   125篇
  2014年   195篇
  2013年   226篇
  2012年   194篇
  2011年   242篇
  2010年   161篇
  2009年   175篇
  2008年   172篇
  2007年   153篇
  2006年   136篇
  2005年   102篇
  2004年   83篇
  2003年   74篇
  2002年   73篇
  2001年   75篇
  2000年   82篇
  1999年   70篇
  1998年   52篇
  1997年   47篇
  1996年   38篇
  1995年   36篇
  1994年   26篇
  1993年   36篇
  1992年   18篇
  1991年   26篇
  1990年   19篇
  1989年   9篇
  1988年   12篇
  1987年   6篇
  1986年   3篇
  1985年   2篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1973年   1篇
排序方式: 共有3537条查询结果,搜索用时 15 毫秒
1.
通过对湖北九宫山国家级自然保护区甜槠群落建立的1ha固定森林样地进行植物群落调查,分析了样地内木本植物物种组成、区系成分、种群径级结构和空间分布格局,结果表明:(1)样地内木本植物(DBH≥1 cm)共有132种,隶属于42科78属,其中,杜鹃花科、壳斗科、樟科、蔷薇科、冬青科等是优势科,短柄袍、鹿角杜鹃、青冈、长叶石栎、甜槠等是优势种.(2)样地内植物科、属的分布类型均以泛热带分布类型为主,分别为30.95%和20.51%.(3)样地内所有木本植物个体的径级结构均呈倒"J"型,幼龄个体数量大,森林群落更新状况良好.(4)样地内木本植物个体的空间分布格局以聚集分布为主,部分优势物种在小尺度上呈聚集分布,而在较大尺度上则为随机分布.  相似文献   
2.
Environmental Science and Pollution Research - The aerodynamic noise around the high-speed railway bridge is studied by the train-bridge-flow field numerical model and theory analysis. With the...  相似文献   
3.
Zhu  Rong  Wang  Shixin  Srinivasakannan  C.  Li  Shiwei  Yin  Shaohua  Zhang  Libo  Jiang  Xiaobin  Zhou  Guoli  Zhang  Ning 《Environmental Chemistry Letters》2023,21(3):1611-1626
Environmental Chemistry Letters - The demand for lithium is growing rapidly with the increase in electric vehicles, batteries and electronic equipments. Lithium can be extracted from brines, yet...  相似文献   
4.
Environmental Science and Pollution Research - Aeration by airflow technology is a reliable method to accelerate waste biodegradation and stabilization and hence shorten the aftercare period of a...  相似文献   
5.
Environmental Science and Pollution Research - Nitrosamines (NAms) are potent genotoxic and carcinogenic but widely detected in drinking water. This study aimed to investigate the occurrence of...  相似文献   
6.
Luo  Dan  Wang  Luyao  Nan  Hongyan  Cao  Yijun  Wang  Hui  Kumar  Thakur Vijay  Wang  Chongqing 《Environmental Chemistry Letters》2023,21(1):497-524
Environmental Chemistry Letters - Phosphorus is essential element for agricultural production, yet phosphorus ore resources are non-renewable and become depleted. Moreover, phosphate release from...  相似文献   
7.
Environmental Science and Pollution Research - Electricity generation is the largest sector with decarbonization potential for China and the world. Based on the new emission factors, this paper...  相似文献   
8.
Environmental Science and Pollution Research - As a persistent organic pollutant, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have gained increasing research attention over...  相似文献   
9.
Environmental Science and Pollution Research - The removal of ammonia nitrogen from wastewater is always a focus in current water treatment. In this study, a combination of mesoporous carbon...  相似文献   
10.
Land degradation is a global problem that seriously threatens human society. However, in China and elsewhere, ecological restoration still largely relies on a traditional approach that focuses only on ecological factors and ignores socioeconomic factors. To improve the effectiveness of ecological restoration and maximize its economic and ecological benefits, a more efficient approach is needed that provides support for policy development and land management and thereby promotes environmental conservation. We devised a framework for assessing the value of ecosystem services that remain after subtracting costs, such as the opportunity costs, costs of forest protection, and costs for the people who are affected by the program; that is, the net value of ecosystem services (NVES). To understand the difference between the value of a resource and the net value of the ecosystem service it provides, we used data on VES, timber sales, and afforestation costs from China's massive national afforestation programs to calculate the net value of forest ecosystem services in China. Accounting for the abovementioned costs revealed an NVES of ¥6.1 × 1012 for forests in 2014, which was 35.9% less than the value calculated without accounting for costs. As a result, the NVES associated with afforestation was 55.9% less than the NVES of natural forests. In some regions, NVES was negative because of the huge costs of human-made plantations, high evapotranspiration rates (thus, high water opportunity costs), and low forest survival rates. To maximize the ecological benefits of conservation, it is necessary to account for as many costs as possible so that management decisions can be based on NVES, thereby helping managers choose projects that maximize both economic and ecological benefits.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号