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   1469篇
  免费   41篇
  国内免费   12篇
安全科学   78篇
废物处理   68篇
环保管理   320篇
综合类   127篇
基础理论   379篇
环境理论   2篇
污染及防治   360篇
评价与监测   106篇
社会与环境   64篇
灾害及防治   18篇
  2023年   16篇
  2022年   26篇
  2021年   22篇
  2020年   14篇
  2019年   24篇
  2018年   32篇
  2017年   34篇
  2016年   45篇
  2015年   44篇
  2014年   42篇
  2013年   107篇
  2012年   83篇
  2011年   98篇
  2010年   68篇
  2009年   90篇
  2008年   96篇
  2007年   92篇
  2006年   89篇
  2005年   65篇
  2004年   61篇
  2003年   53篇
  2002年   51篇
  2001年   13篇
  2000年   18篇
  1999年   20篇
  1998年   18篇
  1997年   17篇
  1996年   18篇
  1995年   21篇
  1994年   24篇
  1993年   14篇
  1992年   13篇
  1991年   8篇
  1990年   8篇
  1989年   10篇
  1988年   5篇
  1987年   2篇
  1986年   3篇
  1985年   9篇
  1984年   4篇
  1983年   9篇
  1982年   9篇
  1981年   5篇
  1980年   5篇
  1979年   3篇
  1978年   2篇
  1977年   4篇
  1976年   2篇
  1964年   1篇
  1957年   2篇
排序方式: 共有1522条查询结果,搜索用时 15 毫秒
1.
2.
Various suggested definitions of the term “traceability” are discussed from the standpoint of proposed adoption and use of the concept by the International Organization of Legal Metrology.  相似文献   
3.
4.
The deposition of trace elements and their fate in a forest ecosystemhas been monitored at the experimental site, Lesni Potok catchment (LP), with granite bedrock. The catchment is located 30 km ESE from Prague. Annual bulk Pb-deposition flux FPb was 3.41 kg km-2 a-1 in 1994 and gradually decreased to 0.49 kg km-2 a-1 in 2001. The decrease is comparable with those observed in Germany and in the U.S.A. in the 1970s and 1980s. The total sales ban of leaded gasoline in the Czech Republic since January 2001 was accompanied by a pronounced decrease of FPb in a single year. The residual Pb-deposition flux is assigned to both the long-range transport of fine-grained vehicular lead aerosol (with a long residence time in the atmosphere) and to theemissions from power plant boilers burning lignite mined in the Czech northwest coal basin. The FPb of lead correlates stronglywith those of As, Cd, Cu, Zn and Be, the typical metals in coal fly ash, at two monitored sites. Topsoil horizons contain elevated concentrations of Pb (53–67 mg kg-1), which are of anthropogenicorigin. Soils in the riparian areas contain increased concentrations of Pb when compared to soils on the hillslope areas. Significant amounts of Pb were found on a stream substrate and Fe-precipitate sampled from the stream. Low concentrations of Pb in bark and bole wood suggest that the uptake of Pb by vegetation is negligible. The very small surface water outputs (average of 0.002 kg km-2 a-1) compared to inputs (average of 1.890 kg km-2 a-1) from the LP catchment indicate an ongoing accumulation of Pb in a forested landscape.  相似文献   
5.
Advancements in technology are inextricably bound to our society and the natural environment. However, how the development process of a technology system interacts with both remains unclear. We propose a process model to understand the complex dynamics among technology, society, and the environment via seven interactive elements: technologies, actors, receiving bodies, natural contexts, social contexts, temporal–spatial contexts, and outcomes. The model was applied to agricultural and water technology development in China from 8000 bc to 1911 ad. Our findings show that these elements did not play equally important roles in different periods of the development in ancient China, with social contexts most dominating during the earlier periods and both social and environmental concerns arising towards the later periods. The proposed model, by identifying the elements in the technology development that should be strengthened, can act as an analysis device to assist in reconfiguring a more sustainable socio-technological system.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01424-7) contains supplementary material, which is available to authorized users.  相似文献   
6.
Journal of Material Cycles and Waste Management - Increasing pressure of the European Union on diverting municipal waste from landfills requires an active role of households and commands a radical...  相似文献   
7.
This article summarizes a long‐term study of vapor intrusion mitigation system performance in a historic, unoccupied residential duplex with an extensive set of temporal variability observations. The experimental design included multiple cycles of subslab depressurization (SSD) system operation and shut‐off during a seven‐month period, followed by a year‐long period of continuous operation. Results showed that the system provided rapid pressure field extension and radon control as much as 100 days of operation before optimum volatile organic compound (VOC) mitigation was achieved. Greater variability in VOC concentrations than in radon concentrations was observed during the initial mitigation system cycling. Subslab VOC concentrations at numerous locations increased during this initial period of SSD operation, and indoor air VOC concentrations were more variable than radon. However, indoor air concentrations were considerably less variable (and lower) during the first year of continuous mitigation system operation. ©2015 Wiley Periodicals, Inc.  相似文献   
8.
Environmental restoration projects can benefit from using performance models tied to monitoring plans and closure/exit strategies. Theoretical aspects are discussed and a case study is provided to illustrate how models can be developed and applied. Recognizing that site characterization cannot remove all uncertainty, most performance models cannot be narrowly developed (e.g., specific concentrations expected over time). Instead they must define threshold values at which performance data indicate the remedy is failing, or at least is not operating at the required level to achieve objectives within a reasonable timeframe. Ultimately, the performance model should be transformed to a closure model. The closure model is intended to document how closure was achieved and what measures remain in place to ensure protection of human health and the environment. In this context, the performance model is an intermediate step in the sequence starting from a conceptual site model and ending as the closure model. © 2014 Wiley Periodicals, Inc.  相似文献   
9.
10.
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