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   1175篇
  免费   47篇
  国内免费   12篇
安全科学   44篇
废物处理   49篇
环保管理   319篇
综合类   93篇
基础理论   294篇
环境理论   1篇
污染及防治   322篇
评价与监测   68篇
社会与环境   33篇
灾害及防治   11篇
  2023年   8篇
  2022年   9篇
  2021年   11篇
  2020年   17篇
  2019年   8篇
  2018年   25篇
  2017年   33篇
  2016年   30篇
  2015年   30篇
  2014年   33篇
  2013年   113篇
  2012年   52篇
  2011年   58篇
  2010年   49篇
  2009年   53篇
  2008年   62篇
  2007年   66篇
  2006年   65篇
  2005年   38篇
  2004年   36篇
  2003年   43篇
  2002年   42篇
  2001年   25篇
  2000年   35篇
  1999年   20篇
  1998年   19篇
  1997年   17篇
  1996年   27篇
  1995年   22篇
  1994年   16篇
  1993年   13篇
  1992年   15篇
  1991年   7篇
  1990年   8篇
  1989年   15篇
  1988年   10篇
  1987年   21篇
  1986年   8篇
  1985年   6篇
  1984年   9篇
  1983年   6篇
  1982年   13篇
  1981年   4篇
  1980年   4篇
  1979年   9篇
  1978年   6篇
  1977年   4篇
  1975年   2篇
  1974年   2篇
  1972年   3篇
排序方式: 共有1234条查询结果,搜索用时 15 毫秒
131.
132.
133.
This article presents a case study of an accelerated cleanup conducted by EPA at the Adams Plating Company (APC) Superfund site near Lansing, Michigan. The APC site remediation was a Superfund EPA-lead project under the remedial program in Region 5. An accelerated cleanup was possible at the APC site by consistently identifying, evaluating, and implementing opportunities to streamline the remedial investigation (RI) and remedial design (RD) process. Streamlining opportunities were discovered and implemented in both the technical and administrative aspects of the project. Streamlining components used to accelerate the remedial process included: (1) extensive use of field screening techniques during the Phase II RI; (2) a focused feasibility study (FS) that evaluated only practical alternatives; (3) maintaining project momentum by initiating the RD concurrent with the issuance of the Record of Decision (ROD); (4) a highly accelerated RD with limited predesign work; (5) elimination of the transition period between RD and remedial action (RA) project phases; (6) frequent and effective communication, coordination, and cooperation between all parties involved (EPA, Michigan Department of Natural Resources (MDNR), technical contractor, PRC Environmental Management, Inc. (PRC), and the public); (7) maintaining a consistent project team throughout project duration; and (8) the setting of aggressive project goals.  相似文献   
134.
135.
Recent studies suggest that nearshore oceanographic conditions can have important effects on the structure of benthic communities. On Santa Cruz Island (SCI), CA, USA there is a persistent difference in mean annual sea surface temperature (SST) around the island due to its location at the confluence of opposing cold and warm ocean current systems. Over the course of a 4-year study (1997–2001) seawater nutrient and chl-a concentrations, algal tissue C:N ratios, recruitment and growth of filter-feeders (barnacles and mussels), and intertidal community structure were measured at six intertidal sites around the island. There were strong associations between remotely sensed SST and patterns of community structure. Macrophyte abundance was highest at sites with persistently low SST, while recruitment, abundance, and growth of filter-feeding invertebrates were strongly, positively correlated with SST. The cold-water sites were associated with higher nutrient concentrations and lower algal C:N ratios, particularly in the winter months. Values of chl-a were generally low and variable among sites, and were not correlated with the predominant SST gradient. Recruitment of barnacles and mussels was positively correlated with adult abundance across all sites. While detailed experimental studies are needed to further evaluate the mechanisms underlying community dynamics, these results indicate that the confluence of cold- and warm-water masses around SCI may determine the contrasting patterns of intertidal community structure.  相似文献   
136.
137.
This paper explores the general reasons for the sudden decline in the growth of world metal demand which began after 1974 and continues to impact the metal industries. For all of the eight metals studied, except aluminium, the dominant cause of this atrophy in demand is the stagnation in total world economic growth, which has caused reduced demand for all goods and services. In addition, consumer preferences have shifted away from metal-intensive goods, further reducing the need for metals. However, materials substitutions and manufacturing technologies have continued to evolve towards lower use of metal in each product at much the same rate after 1974 as before. Therefore, these aspects do not explain the sudden shortfall after 1974 except in the case of aluminium which experienced a dramatic change during the energy crisis years.  相似文献   
138.
139.
The results of more than 1 yr of air monitoring inside and outside of five homes in each of two communities are presented for SO2, NO2, mass respirable particles, SO4, Al, Br, Cl, Mn, Na, and V. Outdoor measurements across the home site in each city are consistent with proximity to outdoor sources. Looking across indoor residential sites in each city, the home appears to alter outdoor concentrations in several ways. Indoor level of SO2, SO4, Mn, and V are lower than those measured outdoors. These constituents are thought generally to result from outdoor sources. The other constituents studied are at times found in excess within homes. In some cases the source or sources of excess concentration of a particular constituent could be identified; often, however, the source of excess indoor concentration could not be identified.  相似文献   
140.
Environmental technology development, like other ventures, requires decisions regarding where to invest scarce capital. The investment option that offers the greatest benefit relative to the cost should be chosen. The problem is to determine a way to analyze the project and apply a useful measure for comparison to other investment opportunities. In this article, three methods of analysis are presented: return on investment, benefit-to-cost ratio, and payback period. Formulas are developed for each of the methods, and a case study illustrates their application.  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