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   370篇
  免费   3篇
  国内免费   4篇
安全科学   13篇
废物处理   12篇
环保管理   58篇
综合类   96篇
基础理论   55篇
环境理论   1篇
污染及防治   119篇
评价与监测   7篇
社会与环境   16篇
  2022年   4篇
  2021年   13篇
  2019年   4篇
  2018年   6篇
  2017年   7篇
  2016年   13篇
  2015年   9篇
  2014年   10篇
  2013年   40篇
  2012年   17篇
  2011年   17篇
  2010年   19篇
  2009年   5篇
  2008年   19篇
  2007年   11篇
  2006年   22篇
  2005年   10篇
  2004年   5篇
  2003年   10篇
  2002年   12篇
  2001年   7篇
  1998年   3篇
  1997年   5篇
  1995年   4篇
  1994年   3篇
  1993年   3篇
  1992年   4篇
  1991年   4篇
  1990年   3篇
  1989年   3篇
  1988年   2篇
  1985年   3篇
  1983年   2篇
  1982年   3篇
  1981年   5篇
  1980年   5篇
  1978年   3篇
  1966年   2篇
  1964年   3篇
  1962年   6篇
  1961年   2篇
  1959年   3篇
  1958年   5篇
  1957年   3篇
  1956年   3篇
  1955年   2篇
  1931年   2篇
  1924年   3篇
  1916年   3篇
  1913年   2篇
排序方式: 共有377条查询结果,搜索用时 664 毫秒
361.
362.
A 6-month field intercomparison study on precipitation measurements was performed at Schagerbrug near the west coast in the Netherlands. Twenty bulk sampling systems and two wet-only samplers were evaluated on accuracy, sampling strategy and performance under field conditions. Bulk precipitation fluxes of NO3-, NH4+, H+ and Kjeldahl-N generally could be determined with a greater accuracy than bulk precipitation fluxes of SO4(2-), Na+, Cl-, Mg2+, Ca2+, Alkalinity and H+. Bulk precipitation fluxes of K+ generally had the lowest accuracy. Only 20% of the sampling systems differed less than 10% from the best estimate, whereas most systems (60%) differed more than 20% from the best estimate. The inaccuracy induced by the sampling system appeared to be much larger than that resulting from the analysis of the samples by different laboratories as determined by ring-tests.  相似文献   
363.
364.
365.
Abstract: For a number of years, best management practices (BMPs) have been implemented within the Town Brook watershed as part of a watershed wide effort to reduce phosphorus losses to the New York City water supply reservoirs. Currently, there are no quantitative indications of the effectiveness of these practices at the watershed scale. Additionally, work is needed to evaluate management practice solutions for costs in relation to effectiveness. In this study we develop a methodology for evaluating management solutions to determine the best way(s) to select and place management practices so that pollutant removal targets are met at minimum cost. The study combines phosphorus losses as simulated by the Soil and Water Assessment Tool (SWAT), management practice effectiveness estimates from a predeveloped characterization tool, and practice costs in optimizations using a genetic algorithm. For a user defined target phosphorus removal (60 percent for this study), optimization favors nutrient management plans, crop rotations, contour strip cropping, and riparian forest buffers; the most cost effective scenario achieves a cost effectiveness of 24/kg phosphorus removal per year compared to the 34/kg phosphorus removal per year associated with the current basic implementation scheme. The study suggests that there is a need to evaluate potential solutions prior to implementation and offers a means of generating and evaluating the solutions.  相似文献   
366.
Hepatitis A is the most common among all hepatitis worldwide in spite of an efficient vaccine and improved hygiene. Shellfish-borne outbreaks are still of major concern causing hundreds of cases and huge economical losses in the present context of global food trade. Hepatitis A virus (HAV) is a unique picornavirus with many differences in its molecular biology including both its incapacity to induce the inhibition of the cellular protein synthesis and a highly biased and deoptimized codon usage with respect the cell. The final goal of this intriguing strategy seems to be the need for a fine-tuning control of the translation kinetics, particularly at the capsid coding region, and the underlying mechanism is the use of a right combination of common and rare codons to allow a regulated ribosome traffic rate thus ensuring the proper protein folding. Capsid folding is critical to warrant a high environmental stability for a virus transmitted through the fecal–oral route with long extracorporeal periods.  相似文献   
367.
368.
In recent years, construction safety has been a hot topic in Hong Kong. The Government of the Hong Kong Special Administrative Region (HKSAR) has launched different safety measures to improve the prevailing safety performance of the construction industry. The Pay for Safety Scheme (PFSS) has emerged as one of the major safety initiatives launched within the public sector construction industry since 1996. It aims to encourage the safety awareness by taking the contractor’s pricing for safety-related items out from the consideration of competitive bidding. The objective is to provide a concise review of the prevailing application of PFSS in Hong Kong in general, and to identify and analyse the key benefits of PFSS in construction through an industry-wide empirical questionnaire survey in particular. Altogether, 145 industrial practitioners who have derived extensive hands-on experience with the PFSS construction projects participated in the survey to indicate their levels of agreement to those 14 key benefits identified which were measured and analysed by factor analysis. The results of factor analysis indicated that the 14 individual benefits of implementing PFSS were consolidated under four underlying factors: (1) Enhancing safety climate and attitude; (2) Promoting effective safety-related communication; (3) Streamlining the safety procedures; and (4) Ensuring adequate safety training. A wider application of PFSS should be encouraged with a view to achieving better safety performance within the industry. It is recommended that a similar scheme to PFSS currently applied in Hong Kong may be developed for implementation in other regions or countries for international comparisons.  相似文献   
369.
The ecosystem service concept is recognized as a useful tool to support sustainability in decision-making. In this study, we collaborated with actors in the Helge å catchment, southern Sweden, in an iterative participatory ecosystem service assessment. Through workshops and interviews, we jointly decided which ecosystem services to assess and indicators to use in order to achieve a sense of ownership and a higher legitimacy of the assessment. Subsequently, we explored the landscape-level interactions between the 15 assessed services, and found that the area can be described using three distinct ecosystem service bundles. The iterative, participatory process strengthened our analysis and created a shared understanding and overview of the multifunctional landscape around Helge å among participants. Importantly, this allowed for the generated knowledge to impact local strategic sustainability planning. With this study, we illustrate how similar processes can support local decision-making for a more sustainable future.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01378-w) contains supplementary material, which is available to authorized users.  相似文献   
370.
Nature-based solutions (NBS), understood as actions that use ecosystem processes to address societal needs, can play important roles to future-proof river landscape development for people and nature. However, knowledge gaps exist how NBS can be planned and implemented at landscape scales. This Special Issue brings together insights and experiences from studies of assessing, planning, and implementing NBS in river landscapes in Europe and beyond. It addresses three research fields: (i) NBS effects, looking at the effectiveness of NBS to achieve ecological, social, and/or economic outcomes, (ii) NBS planning, focusing on approaches for planning and designing NBS, and (iii) NBS governance, relating to governance and business models for implementation. The twelve contributions deliver evidence on how NBS outperform conventional, rather technical solutions, provide guidance and tools to operationalize the NBS concept into practice, and showcase successful governance models of NBS in different contexts. The editorial ends with an outlook on further research needs.  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