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   636篇
  免费   13篇
  国内免费   11篇
安全科学   64篇
废物处理   17篇
环保管理   156篇
综合类   129篇
基础理论   150篇
污染及防治   91篇
评价与监测   31篇
社会与环境   18篇
灾害及防治   4篇
  2023年   7篇
  2022年   4篇
  2021年   13篇
  2020年   16篇
  2019年   6篇
  2018年   18篇
  2017年   15篇
  2016年   26篇
  2015年   17篇
  2014年   22篇
  2013年   46篇
  2012年   20篇
  2011年   41篇
  2010年   20篇
  2009年   27篇
  2008年   32篇
  2007年   28篇
  2006年   31篇
  2005年   29篇
  2004年   19篇
  2003年   22篇
  2002年   26篇
  2001年   14篇
  2000年   20篇
  1999年   6篇
  1998年   7篇
  1997年   5篇
  1996年   10篇
  1995年   11篇
  1994年   9篇
  1993年   6篇
  1992年   9篇
  1991年   8篇
  1990年   5篇
  1988年   8篇
  1987年   5篇
  1986年   3篇
  1985年   4篇
  1984年   2篇
  1983年   5篇
  1982年   6篇
  1981年   10篇
  1980年   6篇
  1979年   2篇
  1977年   3篇
  1974年   2篇
  1973年   3篇
  1970年   1篇
  1962年   1篇
  1956年   1篇
排序方式: 共有660条查询结果,搜索用时 169 毫秒
551.
This study examines the extent to which employee judgments about distributive and procedural justice predict job satisfaction, intent to stay and evaluation of supervision in Hong Kong. Distributive and procedural justice each plays a role in determining work outcomes of Hong Kong employees. However, some effects of these justice variables differ from results of previous studies in the United States (U.S.). First, in previous U.S. studies, procedural justice moderates the relationship of distributive justice with evaluation of supervision, but not with job satisfaction or intent to stay. For Hong Kong employees, procedural justice moderates the effects of distributive justice on job satisfaction and intent to stay, but not on evaluation of supervision. Second, previous U.S. studies have shown that procedural justice has a larger effect on work outcomes for women, while distributive justice has larger effects on outcomes for men. For Hong Kong employees, the effects of procedural and distributive justice are about the same for men and women. Differences in the effects of distributive and procedural justice between Hong Kong and the U.S. may reflect cultural dimensions, such as collectivism/individualism and power distance, as well as the relative availability of rewards for women in the work force. Practical implications and future research directions are discussed. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   
552.
Environment, Development and Sustainability - This paper explored the link between energy consumption and carbon emissions in North Africa through an Environmental Kuznets Curve (EKC) framework....  相似文献   
553.
Traditional high resolution mass spectrometry (HRMS) analysis for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) can be time consuming and expensive. Consequently, alternative methods are of great interest to regulatory agencies and others characterizing contaminated sites. One factor that hinders acceptance of alternative methods is a lack of performance information that assesses the alternative method's impacts on analytical results. The U.S. Environmental Protection Agency's Superfund Innovative Technology Evaluation Monitoring and Measurement Technologies Program (EPA SITE MMT) encourages the development and implementation of innovative and alternative monitoring methods by providing performance information on site characterization technologies. This paper presents a comparison of the results obtained from laboratory-based alternative approaches for screening sediment and soil samples for dioxin toxicity equivalents (TEQ(D/F)) to results obtained using traditional HRMS. The laboratory-based approaches included modifying the traditional HRMS analysis to make it more cost-effective (alternate 1613B), analyzing extracts that had been prepared for HRMS using low resolution mass spectrometry, and determining total organic carbon (TOC) content as an indicator of PCDD/F content. These comparisons demonstrated that TEQ(D/F) values generated using toxicity equivalency factors proposed by the World Health Organization in 1998 applied to alternate 1613B and LRMS analyses have a strong linear correlation to the TEQ(D/F) values derived in the same fashion from traditional HRMS analysis. These results would have placed >90% of the samples within the same concentration intervals using ranges of <0.05, 0.05-0.50, 0.50-5, and >5ng TEQ/g. Natural log transformed data for TOC had significantly weaker correlation to TEQ(D/F), indicating that TOC is not a reliable indicator of TEQ(D/F) concentrations.  相似文献   
554.
Abstract: We used experimental nests baited with California Quail (  Callipepla californica ) eggs or clay eggs to examine relative risks of nest predation in an agricultural landscape and in two large forest preserves in a south-temperate rainforest in Chile. The most common predators, as identified by marks on clay eggs, were a caracara (   Milvago chimango ), a blackbird ( Curaeus curaeus ), and rodents. Nest losses from predation were similar in large and small forest patches and lower in patches than in extensive forest. In general, predation risk was higher (and nest survival therefore lower) on forest edges than in forest interior, in short-grass pasture than in tall-grass pasture, in narrow corridors than in wide corridors, and on visible nests than on concealed nests. High predation risks in pasture habitat tended to increase the risk of nest predation in adjacent forest edges. For open-cup nesters, the risk of nest predation was relatively high in the present agricultural landscape, indicating that much of the available wooded habitat (  forest edges, narrow corridors) offers poor nesting habitat, although it may be suitable for foraging and traveling. The numerous bird-plant mutualisms in this landscape may be at risk if nesting success of the principal mutualists is consistently low.  相似文献   
555.
Abstract: We discuss several challenges encountered in peer review of Endangered Species Act listings and recovery plans, with particular attention to Meffe et al.'s (1998) statement on independent scientific review in natural resource management. First, Endangered Species Act listing documents and recovery plans pose a diverse array of scientific questions, and we suggest that overall effectiveness of peer review may be increased by segregating the critical issues and identifying specific reviewers for each issue. Some scientific reviewers may be unfamiliar with the decision standards prescribed by the Endangered Species Act and implementing policies. Unnecessary confusion could be prevented by providing reviewers with information about these standards and by requesting that reviewers clearly differentiate their assessment of decisions that must be based on available information from recommendations for future research. Short review periods constitute another constraint on careful review, but tight deadlines are fairly intractable in the context of the Endangered Species Act. We suggest that short time frames could be partially ameliorated by narrowing the scope of issues to be treated by each reviewer, and we discuss the issue of providing monetary compensation for efficient review. Finally, Endangered Species Act listing decisions and recovery planning may profit from more frequent peer review of intermediate analyses that precede publication of formal proposals or complete plans.  相似文献   
556.
To better understand the dynamics of contaminant uptake in outmigrant juvenile salmon in the Pacific Northwest, concentrations of polychlorinated biphenyls (PCBs), DDTs, polycylic aromatic hydrocarbons (PAHs) and organochlorine pesticides were measured in tissues and prey of juvenile chinook and coho salmon from several estuaries and hatcheries in the US Pacific Northwest. PCBs, DDTs, and PAHs were found in tissues (whole bodies or bile) and stomach contents of chinook and coho salmon sampled from all estuaries, as well as in chinook salmon from hatcheries. Organochlorine pesticides were detected less frequently. Of the two species sampled, chinook salmon had the highest whole body contaminant concentrations, typically 2--5 times higher than coho salmon from the same sites. In comparison to estuarine chinook salmon, body burdens of PCBs and DDTs in hatchery chinook were relatively high, in part because of the high lipid content of the hatchery fish. Concentrations of PCBs were highest in chinook salmon from the Duwamish Estuary, the Columbia River and Yaquina Bay, exceeding the NOAA Fisheries' estimated threshold for adverse health effects of 2400 ng/g lipid. Concentrations of DDTs were especially high in juvenile chinook salmon from the Columbia River and Nisqually Estuary; concentrations of PAH metabolites in bile were highest in chinook salmon from the Duwamish Estuary and Grays Harbor. Juvenile chinook salmon are likely absorbing some contaminants during estuarine residence through their prey, as PCBs, PAHs, and DDTs were consistently present in stomach contents, at concentrations significantly correlated with contaminant body burdens in fish from the same sites.  相似文献   
557.
Accurate records of high‐resolution rainfall fields are essential in urban hydrology, and are lacking in many areas. We develop a high‐resolution (15 min, 1 km2) radar rainfall data set for Charlotte, North Carolina during the 2001‐2010 period using the Hydro‐NEXRAD system with radar reflectivity from the National Weather Service Weather Surveillance Radar 1988 Doppler weather radar located in Greer, South Carolina. A dense network of 71 rain gages is used for estimating and correcting radar rainfall biases. Radar rainfall estimates with daily mean field bias (MFB) correction accurately capture the spatial and temporal structure of extreme rainfall, but bias correction at finer timescales can improve cold‐season and tropical cyclone rainfall estimates. Approximately 25 rain gages are sufficient to estimate daily MFB over an area of at least 2,500 km2, suggesting that robust bias correction is feasible in many urban areas. Conditional (rain‐rate dependent) bias can be removed, but at the expense of other performance criteria such as mean square error. Hydro‐NEXRAD radar rainfall estimates are also compared with the coarser resolution (hourly, 16 km2) Stage IV operational rainfall product. Stage IV is adequate for flood water balance studies but is insufficient for applications such as urban flood modeling, in which the temporal and spatial scales of relevant hydrologic processes are short. We recommend the increased use of high‐resolution radar rainfall fields in urban hydrology.  相似文献   
558.
Population viability analysis (PVA) is a powerful conservation tool, but it remains impractical for many species, particularly species with multiple, broadly distributed populations for which collecting suitable data can be challenging. A recently developed method of multiple-population viability analysis (MPVA), however, addresses many limitations of traditional PVA. We built on previous development of MPVA for Lahontan cutthroat trout (LCT) (Oncorhynchus clarkii henshawi), a species listed under the U.S. Endangered Species Act, that is distributed broadly across habitat fragments in the Great Basin (U.S.A.). We simulated potential management scenarios and assessed their effects on population sizes and extinction risks in 211 streams, where LCT exist or may be reintroduced. Conservation populations (those managed for recovery) tended to have lower extinction risks than nonconservation populations (mean = 19.8% vs. 52.7%), but not always. Active management or reprioritization may be warranted in some cases. Eliminating non-native trout had a strong positive effect on overall carrying capacities for LCT populations but often did not translate into lower extinction risks unless simulations also reduced associated stochasticity (to the mean for populations without non-native trout). Sixty fish or 5–10 fish/km was the minimum reintroduction number and density, respectively, that provided near-maximum reintroduction success. This modeling framework provided crucial insights and empirical justification for conservation planning and specific adaptive management actions for this threatened species. More broadly, MPVA is applicable to a wide range of species exhibiting geographic rarity and limited availability of abundance data and greatly extends the potential use of empirical PVA for conservation assessment and planning.  相似文献   
559.
The decision gym: decision insurance for organizations   总被引:1,自引:1,他引:0  
Conducting decision calisthenics can help an organization win competitive advantage through harnessing its tremendous knowledge, imagination, and staff experience. The paper explores how knowledge and experience mined and refined through innovative approaches like scenarios and war gaming can turn visionary ideas into successful, working realities. To fully appreciate the value of novel frameworks requires contextualizing their utility in what can be called the decision gym. The decision gym offers a way to build powerful consensus and commitment to decisions, methods to optimize processes, and a way to create, evaluate, and execute critical strategies in the face of heuristics and biases that can distort decision making.  相似文献   
560.
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