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   404篇
  免费   11篇
  国内免费   3篇
安全科学   23篇
废物处理   22篇
环保管理   104篇
综合类   20篇
基础理论   98篇
污染及防治   102篇
评价与监测   14篇
社会与环境   12篇
灾害及防治   23篇
  2022年   2篇
  2021年   3篇
  2020年   8篇
  2019年   3篇
  2018年   9篇
  2017年   5篇
  2016年   9篇
  2015年   12篇
  2014年   11篇
  2013年   28篇
  2012年   14篇
  2011年   19篇
  2010年   15篇
  2009年   15篇
  2008年   13篇
  2007年   20篇
  2006年   17篇
  2005年   13篇
  2004年   13篇
  2003年   14篇
  2002年   26篇
  2001年   4篇
  2000年   7篇
  1999年   7篇
  1998年   9篇
  1997年   6篇
  1996年   7篇
  1995年   3篇
  1994年   7篇
  1993年   9篇
  1991年   4篇
  1990年   2篇
  1989年   5篇
  1988年   3篇
  1987年   2篇
  1986年   3篇
  1985年   6篇
  1984年   4篇
  1983年   3篇
  1982年   10篇
  1981年   7篇
  1980年   6篇
  1979年   7篇
  1978年   5篇
  1977年   7篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1971年   3篇
排序方式: 共有418条查询结果,搜索用时 296 毫秒
301.
In an effort to explore the role of new media technologies in environmental protest rhetoric, this paper examines Greenpeace's Let's Go! Arctic campaign, which opposed Shell's Arctic oil-drilling plans. The campaign produced a body of Internet memes designed to look like Shell's own corporate advertising. Moreover, the viral campaign used various rhetorical techniques that challenged Shell's goals and identity. Greenpeace-generated and user-generated memes cleverly use irony, corporate voice and humor to delegitimize Shell's Arctic efforts. The memes offered messages that mocked corporate practices and corporate messaging while also providing direct protest messages and accessible humor that invited identification against Shell. Thus, the memes collectively encouraged identification with Greenpeace's antidrilling, pro-environment discourse.  相似文献   
302.
Rising human demand and climatic variability have created greater uncertainty regarding global food trade and its effects on the food security of nations. To reduce reliance on imported food, many countries have focused on increasing their domestic food production in recent years. With clear goals for the complete self-sufficiency of rice production, Sri Lanka provides an ideal case study for examining the projected growth in domestic rice supply, how this compares to future national demand, and what the associated impacts from water and fertilizer demands may be. Using national rice statistics and estimates of intensification, this study finds that improvements in rice production can feed 25.3 million Sri Lankans (compared to a projected population of 23.8 million people) by 2050. However, to achieve this growth, consumptive water use and nitrogen fertilizer application may need to increase by as much as 69 and 23 %, respectively. This assessment demonstrates that targets for maintaining self-sufficiency should better incorporate avenues for improving resource use efficiency.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0720-2) contains supplementary material, which is available to authorized users.  相似文献   
303.
China produces the largest amount of pork in the world, which emits the largest amount of greenhouse gases (GHGs). This paper calculates GHG emissions from China’s hog production at the provincial level using newly published emission factors. Empirical results show that GHG emissions from China’s hog production mainly respond to the scale intensity. Capital abundance and income contribute positively to GHG emissions from hog production. Pork trade increases GHG emissions from China’s hog production with a significantly direct effect, reduces GHG emissions through indirect technique effects.  相似文献   
304.
The accuracy of individuals to estimate the opacity of black and white plumes in Visible Emission Training Programs is analyzed. The analysis includes new students and individuals returning for recertification. Following a set of drills, students generally have accuracy only slightly lower than those achieving certification. The accuracy of individuals during their initial recertification attempt is virtually the same as the accuracy six months earlier when they passed the certification test. The most important skill to reading opacity is an unshakable mental impression of plumes having 25, 50 and 75 percent opacity.  相似文献   
305.
The 2005 hurricane season caused extensive damage and induced a mass migration of approximately 1.1 million people from southern Louisiana in the United States. Current and accurate estimates of population size and demographics and an assessment of the critical needs for public services were required to guide recovery efforts. Since forecasts using pre-hurricane data may produce inaccurate estimates of the post-hurricane population, a household survey in 18 hurricane-affected parishes was conducted to provide timely and credible information on the size of these populations, their demographics and their condition. This paper describes the methods used, the challenges encountered, and the key factors for successful implementation. This post-disaster survey was unique because it identified the needs of the people in the affected parishes and quantified the number of people with these needs. Consequently, this survey established new population and health indicator baselines that otherwise would have not been available to guide the relief and recovery efforts in southern Louisiana.  相似文献   
306.
The proportions of manganese to other metals in samples of airborne fine particles taken at some sites in California have increased greatly since the beginning of 1985. Here, data are presented which indicate that the addition of manganese to leaded gasoline is largely responsible for this increase. Concentrations of manganese, silicon, titanium, iron, lead and other elements in airborne particles were measured using energy-dispersive X-ray fluorescence analysis. Coefficients of correlation among levels of manganese, iron and lead measured at twenty sites in California were calculated. Levels of manganese and iron are generally highly correlated because of the presence of large amounts of these elements in the earth’s crust. Levels of airborne manganese and lead at sites In Southern California are often highly correlated, suggesting a vehicular source of manganese. Observed manganese concentrations are apportioned into two major sources: the earth’s crust and motor vehicles. The apportionment indicates that vehicular emissions of manganese may account for a significant part of the total at urban sites in Southern California. At most other sites, the contribution from vehicles is found to be far smaller than that from the earth’s crust.  相似文献   
307.
Mining of the Butte deposit evolved over 100 years from placer mining starting in 1864 through silver mining to copper mining in the 1900s. Tailings resulting from milling during the period 1876-1924 were typically sluiced into the adjacent Silver Bow Creek (SBC) where they were washed downstream. The most significant flood event in 1908, among others, resulted in emplacement of approximately 2.9 m tons of sediment intermixed with tailings as overbank deposits along SBC between Butte and the Warm Springs Ponds. Apportioning the associated costs was contingent in part on discriminating between ownership of liability for the silver and copper tailings, which together formed the most significant portion of the overbank deposits. Samples were collected of tailings end-members and SBC deposits and their characteristic mineralogy (e.g. galena for silver tailings, and enargite for copper tailings) used to ascertain mixing of the tailings along SBC. This analysis identified Pb as a signature element for silver tailings and Cu for copper tailings. Two-hundred and twenty-four Cu and Pb chemical analyses representing 43 transects through the overbank deposits along SBC allowed calculation of the proportional contribution of the end members for each integrated transect. Accumulating the volumes from each transect resulted in an apportionment of 53% copper and 47% silver tailings in the overbank deposits.  相似文献   
308.
Identifying and quantifying the contributions of multiple sources of trace elements to stream sediments in a basin containing several possible inputs presents a unique problem related to the investigation of rivers impacted by industrial activity. A multi-source dilution-mixing model was developed and applied to determine the relative contributions to As, Cu and Pb burdens in the Clark Fork River, Montana, a recipient of historical mine wastes as a result of over a century of mining and milling operations. The results identified the Flint Creek drainage as a major source of anthropogenic As (47%) and Pb (35%) to sediments of the Clark Fork River and the Milltown Reservoir, in addition to the major sources associated with mining operations in Butte, MT. The Little Blackfoot River also contributes anthropogenic As (3%) and Pb (4%) to the Clark Fork River, while minor inputs of Cu (1%) and Pb (2%) emanate from the Blackfoot River. The model allows source quantification, and an understanding of the fate and transport of mine wastes in a basin, allowing identification and eventual prioritization of sites destined for remediation.  相似文献   
309.
The effect of phenol concentration on phenol biodegradation at an industrial site in the south of Wales, United Kingdom, was investigated using standard Bio‐Sep® Bio‐Traps® and Bio‐Traps® coupled with stable isotope probing (SIP). Unlike many 13C‐amendments used in SIP studies (such as hydrocarbons) that physically and reversibly adsorb to the activated carbon component of the Bio‐Sep® beads, phenol is known to irreversibly chemisorb to activated carbon. Bio‐Traps® were deployed for 32 days in nine site groundwater monitoring wells representing a wide range of phenol concentrations. Bio‐Traps® amended with 13C‐phenol were deployed together with non‐amended Bio‐Traps® in three wells. Quantitative polymerase chain reaction (qPCR) analysis of Bio‐Traps® post‐deployment indicated an inhibitory effect of increasing phenol concentration on both total eubacteria and aerobic phenol‐utilizing bacteria as represented by the concentration of phenol hydroxylase gene. Despite the chemisorption of phenol to the Bio‐Sep® beads, activated carbon stable isotope analysis showed incorporation of 13C into biomass and dissolved inorganic carbon (DIC) in each SIP Bio‐Trap® indicating that chemisorbed amendments are bioavailable. However, there was a clear effect of phenol concentration on 13C incorporation in both biomass and DIC confirming phenol inhibition. These results suggest that physical reductions of the phenol concentrations in some areas of the plume will be required before biodegradation of phenol can proceed at a reasonable rate. © 2013 Wiley Periodicals, Inc.  相似文献   
310.
Urban Transitions: On Urban Resilience and Human-Dominated Ecosystems   总被引:3,自引:0,他引:3  
Urbanization is a global multidimensional process paired with increasing uncertainty due to climate change, migration of people, and changes in the capacity to sustain ecosystem services. This article lays a foundation for discussing transitions in urban governance, which enable cities to navigate change, build capacity to withstand shocks, and use experimentation and innovation in face of uncertainty. Using the three concrete case cities—New Orleans, Cape Town, and Phoenix—the article analyzes thresholds and cross-scale interactions, and expands the scale at which urban resilience has been discussed by integrating the idea from geography that cities form part of “system of cities” (i.e., they cannot be seen as single entities). Based on this, the article argues that urban governance need to harness social networks of urban innovation to sustain ecosystem services, while nurturing discourses that situate the city as part of regional ecosystems. The article broadens the discussion on urban resilience while challenging resilience theory when addressing human-dominated ecosystems. Practical examples of harnessing urban innovation are presented, paired with an agenda for research and policy.  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