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   461篇
  免费   13篇
  国内免费   5篇
安全科学   13篇
废物处理   17篇
环保管理   90篇
综合类   58篇
基础理论   136篇
环境理论   1篇
污染及防治   90篇
评价与监测   33篇
社会与环境   24篇
灾害及防治   17篇
  2023年   4篇
  2022年   5篇
  2021年   7篇
  2020年   12篇
  2019年   10篇
  2018年   10篇
  2017年   16篇
  2016年   22篇
  2015年   12篇
  2014年   20篇
  2013年   26篇
  2012年   22篇
  2011年   37篇
  2010年   23篇
  2009年   19篇
  2008年   15篇
  2007年   24篇
  2006年   15篇
  2005年   16篇
  2004年   16篇
  2003年   16篇
  2002年   9篇
  2001年   13篇
  2000年   10篇
  1999年   8篇
  1998年   6篇
  1997年   5篇
  1996年   4篇
  1994年   8篇
  1993年   2篇
  1992年   3篇
  1991年   3篇
  1990年   2篇
  1989年   3篇
  1988年   6篇
  1986年   5篇
  1985年   8篇
  1984年   6篇
  1983年   2篇
  1982年   7篇
  1980年   3篇
  1978年   5篇
  1976年   2篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1972年   1篇
  1971年   3篇
  1968年   1篇
  1958年   1篇
排序方式: 共有479条查询结果,搜索用时 46 毫秒
471.
The above article from Disasters, published online on 24 June 2019 in Wiley Online Library ( http://wileyonlinelibrary.com ) has been withdrawn by agreement among the authors, the Journal editors and John Wiley & Sons Inc. on behalf of ODI. The withdrawal has been agreed because this is a duplicate of an article that has been published in Disasters Volume 44 Issue 1.  相似文献   
472.
473.
This paper sets out to show how urban sustainability issues have been addressed by social, political, and economic actors involved in housing production in Montréal. Specifically, it looks at how the environmental question has been incorporated into the practice and discourse of recent housing schemes. Principles of sustainable development such as adaptive reuse of industrial buildings and infill housing that allow for reinvestment in inner-city neighbourhoods, inclusion of affordable, or social housing in private housing developments to secure social mix, citizen participation, energy, water, and transportation matters have been increasingly circulated. By examining planning documents, design proposals, and briefs presented at public hearings on housing schemes in Southwest Montréal, a former working-class borough undergoing revitalisation, this paper shows that the values of sustainable development have been used by both private developers and local authorities to negotiate urban transformations with community groups.  相似文献   
474.
The COVID-19 pandemic has had an enormous impact on almost all aspects of human society and endeavor; the natural world and its conservation have not been spared. Through a process of expert consultation, we identified and categorized, into 19 themes and 70 subthemes, the ways in which biodiversity and its conservation have been or could be affected by the pandemic globally. Nearly 60% of the effects have been broadly negative. Subsequently, we created a compendium of all themes and subthemes, each with explanatory text, and in August 2020 a diverse group of experienced conservationists with expertise from across sectors and geographies assessed each subtheme for its likely impact on biodiversity conservation globally. The 9 subthemes ranked highest all have a negative impact. These were, in rank order, governments sidelining the environment during their economic recovery, reduced wildlife-based tourism income, increased habitat destruction, reduced government funding, increased plastic and other solid waste pollution, weakening of nature-friendly regulations and their enforcement, increased illegal harvest of wild animals, reduced philanthropy, and threats to survival of conservation organizations. In combination, these impacts present a worrying future of increased threats to biodiversity conservation but reduced capacity to counter them. The highest ranking positive impact, at 10, was the beneficial impact of wildlife-trade restrictions. More optimistically, among impacts ranked 11-20, 6 were positive and 4 were negative. We hope our assessment will draw attention to the impacts of the pandemic and, thus, improve the conservation community's ability to respond to such threats in the future.  相似文献   
475.
Nonpoint source pollution from agriculture and urbanization is increasing globally at the same time climate extremes have increased in frequency and intensity. We review >200 studies of hydrologic and gaseous fluxes and show how the interaction between land use and climate variability alters magnitude and frequency of carbon, nutrient, and greenhouse gas pulses in watersheds. Agricultural and urban watersheds respond similarly to climate variability due to headwater alteration and loss of ecosystem services to buffer runoff and temperature changes. Organic carbon concentrations/exports increase and organic carbon quality changes with runoff. Nitrogen and phosphorus exports increase during floods (sometimes by an order of magnitude) and decrease during droughts. Relationships between annual runoff and nitrogen and phosphorus exports differ across land use. CH4 and N2O pulses in riparian zones/floodplains predominantly increase with: flooding, warming, low oxygen, nutrient enrichment, and organic carbon. CH4, N2O, and CO2 pulses in streams/rivers increase due to similar factors but effects of floods are less known compared to base flow/droughts. Emerging questions include: (1) What factors influence lag times of contaminant pulses in response to extreme events? (2) What drives resistance/resilience to hydrologic and gaseous pulses? We conclude with eight recommendations for managing watershed pulses in response to interactive effects of land use and climate change.  相似文献   
476.
Bracken (Pteridium aquilinum) is a major problem for livestock-based extensive agriculture, conservation, recreation, and game management globally. It is an invasive species often achieving dominance to the detriment of other species. Control is essential to maintain plant communities such as grassland and lowland heath or if extensive grazing by domestic stock, particularly sheep, is to be viable on upland margins. Bracken is managed primarily by herbicide application or cutting but other techniques including rolling, burning, and grazing are also utilized. Here we evaluate the evidence regarding the effectiveness of asulam for the control of bracken. Thirteen studies provided data for meta-analyses which demonstrate that application of the herbicide asulam reduces bracken abundance. Subgroup analyses indicate that the number of treatments had an important impact, with multiple follow-up treatments more effective than one or two treatments. Management practices should reflect the requirement for repeated follow-up. There is insufficient available experimental evidence for quantitative analysis of the effectiveness of other management interventions, although this results from lack of reporting in papers where cutting and comparisons of cutting and asulam application are concerned. Systematic searching and meta-analytical synthesis have effectively demonstrated the limits of current knowledge, based on recorded empirical evidence, and increasing the call for more rigorous monitoring of bracken control techniques. Lack of experimental evidence on the effectiveness of management such as rolling or grazing with hardy cattle breeds contrasts with the widespread acceptance of their use through dissemination of experience.  相似文献   
477.
Humic-like substances (HLS) were extracted from a mixture of sewage sludges and trimmings (70-30%, w/w) after different times of composting (0, 70 days and 130 days). HLS were analyzed by elemental analysis, UV-visible and fluorescence spectroscopy and also tested for their ability to photosensitize the degradation of Irgarol. The rate of Irgarol photodegradation in artificial solar light was found to be 2.5- to 4.3-fold higher in the presence of HLS than in buffered Milli-Q water. These results were confirmed by experiments in solar light that evidenced the photodegrading properties of HLS in a more striking way. Using 2-propanol as hydroxyl radical scavenger, we could show that hydroxyl radicals contributed to the photosensitized Irgarol degradation for about 25%. The photodegrading activity of HLS, their absorbance and their emissive properties were all found to increase between 0 and 70 days of composting and to remain quite constant between 70 and 130 days. The degree of humification varied in the same way, linking all these properties to the humification process.  相似文献   
478.
PROBLEM: In many jurisdictions, driver education (DE) graduates, compared to non-graduates, are granted a time-discount that allows them to drive unsupervised several months earlier, despite little evidence of a safety benefit and consistent evidence of increased crash risk. Confounding factors may be threatening the validity of DE evaluations. A theoretical framework called the "licensing process" (LP) is proposed to identify and explore potential confounding factors in DE evaluations. METHOD: Prospective study data on a cohort of 1804 novice drivers 16 to 19 years of age of both sexes are analyzed in relation to the LP framework. These data derive from two sources that were linked together: an extensive questionnaire on learning methods, risk-taking, and lifestyles, and government records on exam performance, violations, and crashes. RESULTS: Violation and crash records are not associated with DE attendance. DE attendance is associated with younger ages, greater financial support from family, and fewer hours of supervised driving practice with a learner's permit. For both sexes, more hours of supervised driving practice with a learner's permit is associated with increased crash risk. Most participants, particularly males under 19 years of age, attended DE partly or entirely to save time or money; these motivations are associated with higher violation and crash rates. DISCUSSION: DE evaluations need to identify and control for potential confounding factors. Research is needed to understand the associations between increased crash risk and potential confounding factors like motivation to attend DE and hours of supervised driving practice.  相似文献   
479.
Farmland diversification practices (i.e., methods used to produce food sustainably by enhancing biodiversity in cropping systems) are sometimes considered beneficial to both agriculture and biodiversity, but most studies of these practices rely on species richness, diversity, or abundance as a proxy for habitat quality. Biodiversity assessments may miss early clues that populations are imperiled when species presence does not imply persistence. Physiological stress indicators may help identify low-quality habitats before population declines occur. We explored how avian stress indicators respond to on-farm management practices and surrounding seminatural area (1-km radius) across 21 California strawberry farms. We examined whether commonly used biodiversity metrics correlate with stress responses in wild birds. We used ∼1000 blood and feather samples and body mass and wing chord measurements, mostly from passerines, to test the effects of diversification practices on four physiological stress indicators: heterophil to lymphocyte ratios (H:L), body condition, hematocrit values, and feather growth rates of individual birds. We then tested the relationship between physiological stress indicators and species richness, abundance, occurrence, and diversity derived from 285 bird point count surveys. After accounting for other biological drivers, landscape context mediated the effect of local farm management on H:L and body condition. Local diversification practices were associated with reduced individual stress in intensive agricultural landscapes but increased it in landscapes surrounded by relatively more seminatural area. Feathers grew more slowly in landscapes dominated by strawberry production, suggesting that nutritional condition was lower here than in landscapes with more crop types and seminatural areas. We found scant evidence that species richness, abundance, occurrence, or diversity metrics were correlated with the individual's physiological stress, suggesting that reliance on these metrics may obscure the impacts of management on species persistence. Our findings underscore the importance of considering landscape context when designing local management strategies to promote wildlife conservation.  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