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   234篇
  免费   9篇
  国内免费   8篇
安全科学   8篇
废物处理   5篇
环保管理   56篇
综合类   24篇
基础理论   75篇
环境理论   1篇
污染及防治   47篇
评价与监测   14篇
社会与环境   16篇
灾害及防治   5篇
  2023年   5篇
  2022年   4篇
  2021年   6篇
  2020年   5篇
  2019年   3篇
  2018年   5篇
  2017年   9篇
  2016年   16篇
  2015年   7篇
  2014年   5篇
  2013年   18篇
  2012年   15篇
  2011年   16篇
  2010年   8篇
  2009年   7篇
  2008年   9篇
  2007年   11篇
  2006年   8篇
  2005年   7篇
  2004年   4篇
  2003年   8篇
  2002年   5篇
  2001年   7篇
  2000年   2篇
  1999年   5篇
  1998年   1篇
  1997年   2篇
  1996年   6篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   4篇
  1991年   2篇
  1990年   5篇
  1989年   2篇
  1988年   6篇
  1987年   3篇
  1986年   2篇
  1985年   2篇
  1984年   3篇
  1983年   5篇
  1982年   3篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1978年   2篇
  1968年   1篇
排序方式: 共有251条查询结果,搜索用时 15 毫秒
151.
The U.S. Department of Defense-approved activities conducted at the Utah Test and Training Range (UTTR) include both operational readiness test firing of intercontinental ballistic missile (ICBM) motors, as well as the destruction of obsolete or otherwise unusable ICBM motors through open burn/open detonation (OB/OD). Within the Utah Division of Air Quality, these activities have been identified as having the potential to generate unacceptable noise levels, as well as significant amounts of volatile organic compounds (VOCs). Hill Air Force Base, UT, has completed a series of field tests at the UTTR in which sound-monitoring surveillance of OB/OD activities was conducted to validate the Sound Intensity Prediction System (SIPS) model. Using results generated by the SIPS model to support the decision to detonate, the UTTR successfully disposed of missile motors having an aggregate net explosive weight (NEW) of 81,374 lb without generating adverse noise levels within populated areas. In conjunction with collecting noise-monitoring data, air emissions were collected to support the development of air emission factors for both static missile motor firings and OB/OD activities. Through the installation of 15 ground-based air samplers, the generation of combustion-fixed gases, VOCs, and chlorides was monitored during the 81,374-lb NEW detonation event. Comparison of field measurements to predictions generated from the US Navy energetic combustion pollutant formation model, POLU4WN, indicated that, as the detonation fire ball expanded, organic compounds, as well as CO, continued to oxidize as the combustion gases mixed with ambient air. VOC analysis of air samplers confirmed the presence of chloromethane, vinyl chloride, benzene, toluene, and 2-methyl-1-propene. Qualitative chloride analysis indicated that gaseous HCl was generated at low concentrations, if at all.  相似文献   
152.
153.
This paper develops a valuation method which generates consistent and systematic estimates of people's preferences for complex multi-attribute goods by inextricably linking auction bids with conjoint ratings. The advantage of the valuation approach is that it permits the estimation of people's values for many potential goods, allows one to decompose people's values for a good into its sub-components, and permits the study of preference heterogeneity without distributional assumptions. We apply the method to an important and increasingly controversial topic: animal welfare. The method is used to determine people's preferences for eggs and pork produced from different production systems. Data from experiments conducted in three diverse U.S. locations (Chicago, IL; Dallas, TX; and Wilmington, NC) indicates that people are, on average, willing to pay $0.95 more for a dozen eggs raised in an aviary, pasture system vs. a cage system, and are willing to pay $2.02 more for two-pounds of pork chops raised in a pasture system as opposed to a crate system.  相似文献   
154.
Social experience can elicit phenotypically plastic changes in mate choice, but little is known about the degree to which social information from one modality can influence mating decisions based on information from a different modality. I used the field cricket Teleogryllus oceanicus to test whether experience of chemical cues mimicking a high density of sexually mature males causes changes in mate choice based on acoustic signals. T. oceanicus males produce long-range calling songs to attract females for mating, but they also produce waxy, non-volatile hydrocarbons on their cuticle (CHCs) which, when deposited on a substrate, can be detected by females and may provide demographic information. I manipulated female experience of substrate-bound male CHCs and then performed acoustic mate choice trials. When CHCs were present on the substrate during trials, females showed greater motivation to respond to male calling song. This effect diminished with repeated exposure to male songs, demonstrating that the importance of olfactory cues in altering acoustic mate choice decreased with increasing exposure to acoustic signals. However, the temporal nature of CHC experience mattered: previous experience of CHCs did not alter subsequent female choice for male calling song traits. Exposure to male song increased the threshold of mate acceptance over time, and individuals varied considerably in overall levels of responsiveness. Taken together, the results demonstrate that mate choice is dependent on social context mediated by multiple modalities in T. oceanicus, but they do not support the idea that prior experience of social cues in one modality necessarily influences later mating decisions based on other signalling modalities.  相似文献   
155.
This study used a mixed methods approach to estimate whether a moral panic occurred after Hurricane Katrina forced the evacuations of more than 250,000 people to Houston, Texas. The study viewed data from the Houston Police Department combined with a qualitative review of references of criminal activity in local print media. In total, over 8,500 lines of text were analysed to discern themes associated with media representations of the influence of evacuees on the city of Houston. There was little evidence of statistically significant increases in crime over the months following the evacuations. There was, however, evidence that evacuees, principally from New Orleans, were blamed for perceived increases in violent crime and lawlessness. There are also significant policy implications for state, local and federal governments. In particular, the policies of the Federal Emergency Management Agency were blamed for at least some of the perceived crime attributed to Katrina evacuees.  相似文献   
156.
Ecological health of 15 sites in two mining areas on the West Coast of the South Island, New Zealand, was assessed using a non-invasive electrophysiological technique. The conduction velocity (CV) changes in the medial giant fibres (MGF) of the terrestrial earthworm Aporrectodea caliginosa were measured on days 0, 1, 2, 4, 7, 14, and 21 following exposure to soil and/or sediment from six acid mine drainage (AMD) sites, and aquatic oligochaete Lumbriculus variegatus at 0, 3, 6, and 24 h following exposure to water from 14 AMD sites. The colour of the soil/sediments varied from red-brown to black with pH ranging from 4.46 to 7.37. The colour of AMD water samples varied from clear, black, brown to orange, and the pH ranged from 2.99 to 7.66. The CV decreased progressively in A. caliginosa exposed to most soil and sediment samples from the AMD sites (compared with controls exposed to soil from an organic farm) and this was most evident in measurements taken at 7 days. Based on the CV measurements taken on day 7, sites 3 > 2 > 1 were significantly (P < 0.05) the most toxic to earthworms. The CV of L. variegatus exposed to AMD water sampled from many sites also decreased progressively and this was significantly lower than the controls in the measurements taken at 24 h from sites 3 > 9 > 7 > 11. It is proposed that MGF CV in A. caliginosa and L. variegatus worms can be used as a non-invasive, sensitive, biomarker to monitor the toxicity of AMD sites.  相似文献   
157.
正Swimming is excellent exercise and offers many health benefits.However,the"chlorine smell"in swimming pools may be a turn-off for some people.Although this smell is often thought to be of chlorine,it actually comes from volatile compounds that are produced from unintended reactions between disinfectants(e.g.,chlorine)and organic matter in  相似文献   
158.
This paper presents an evaluation of the long‐term impact of microfinance programmes on Acehnese children during the post‐tsunami recovery. The study, conducted from June to August 2010, examined the impact of microfinance programming six years after the tsunami. The sample consisted of 185 microfinance participants, with a comparison group of 192 individuals who did not participate in microfinance programmes. All respondents were parents, interviewed through a structured survey. The study used four child protection indicators—diet, health, childcare and education—in contrast to traditional repayment rate indicators. The primary results were insignificant with respect to all four child protection indicators, suggesting that, with respect to these indicators, there was no long‐term difference between the impact of microfinance on beneficiaries' children and non‐beneficiaries' children. These findings signify a need for microfinance actors to move beyond traditional indicators of economic success to evaluate the social changes microfinance programmes are presumed to effect.  相似文献   
159.
As provinces across Canada seek to diversify their domestic electricity supply and cope with the accelerating effects of anthropogenic climate change, new models of sustainability-focused economic development are being pursued. One critically important emerging paradigm involves First Nation (a Canadian term for indigenous) collaboration and leadership in renewable energy projects. In this comparative case study analysis, we consider two different governance approaches pursued in distinct renewable energy project contexts: the clean energy projects of the Ojibway Pic River First Nation band in northwestern Ontario and the NaiKun Offshore Wind Project proposed in the ocean territory of the Haida Nation off the coast of British Columbia (BC). Focusing on themes of participation and multi-level governance, the case studies highlight the importance of authority and control in decision processes, the primacy of ensuring that scale and quality of design are carefully scoped, and the shaping role of inclusiveness in planning for wholly sustainable energy futures. Taken together, these cases illustrate that fluid governance arrangements which exploit the particular capacities of each actor may give rise to trust that ultimately forms the foundation of a co-produced model of renewable energy governance. We argue that while collaboration might aim to be inclusive of all interested actors, it is important to consider the extent to which a project design might sufficiently incorporate a community's long-term vision. We conclude that truly sustainable renewable energy development requires a project design that reflects community values, incorporates community control, and incentivises indigenous ownership.  相似文献   
160.
The waste hierarchy of ‘reduce, reuse, recycle, recover’ can be followed to improve the sustainability of a product, yet it is not applied in any meaningful way in the biomaterials industry which focuses more on sustainable sourcing of inputs. This paper presents the results of industry interviews and a focus group with experts to understand how waste recovery of biomaterials could become more widespread. Interview findings were used to develop three scenarios: (1) do nothing; (2) develop legislation; and (3) develop certification standards. These scenarios formed the basis for discussions at an expert focus group. Experts considered that action was required, rejecting the first scenario. No preference was apparent for scenarios (2) and (3). Experts agreed that there should be collaboration on collection logistics, promotion of demand through choice editing, product ‘purity’ could be championed though certification and there should be significant investment and research into recovery technologies. These considerations were incorporated into the development of a model for policy makers and industry to help increase biomaterial waste recovery.  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