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   161篇
  免费   10篇
  国内免费   1篇
安全科学   7篇
废物处理   1篇
环保管理   28篇
综合类   25篇
基础理论   67篇
污染及防治   26篇
评价与监测   7篇
社会与环境   9篇
灾害及防治   2篇
  2023年   3篇
  2022年   4篇
  2021年   2篇
  2020年   3篇
  2019年   3篇
  2018年   4篇
  2017年   4篇
  2016年   12篇
  2015年   7篇
  2014年   12篇
  2013年   11篇
  2012年   8篇
  2011年   2篇
  2010年   8篇
  2009年   10篇
  2008年   10篇
  2007年   9篇
  2006年   7篇
  2005年   4篇
  2004年   6篇
  2003年   3篇
  2002年   4篇
  2001年   6篇
  2000年   2篇
  1999年   3篇
  1997年   2篇
  1995年   3篇
  1994年   3篇
  1989年   3篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   4篇
  1984年   2篇
  1979年   1篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
  1972年   1篇
排序方式: 共有172条查询结果,搜索用时 31 毫秒
41.
42.
The three largest water utilities in the Washington, D.C., metropolitan area (WMA) rely on the Potomac River and its reservoirs for water supply. These utilities have committed to a periodic review of the system's adequacy to meet future demands. In 1990, 1995, 2000, and again in 2004 (for publication in 2005) the utilities requested that the Interstate Commission on the Potomac River Basin (ICPRB) conduct a 20‐year water demand and resource adequacy study to fulfill this need. The selection of the five‐year interval provides multiple benefits. It allows regular updates and incorporation of recent demographic forecasts, and it increases visibility and understanding of the adequacy of the region's water resources. It also provides adequate time to conduct research on the physical system and to incorporate modifications based on this research into subsequent studies. The studies and lessons learned are presented in this case study of the WMA. The work has been a natural outgrowth of a long history of cooperative water supply planning and management among the main WMA water utilities and ICPRB.  相似文献   
43.
44.
45.
Molecular approaches to microbiological monitoring: fecal source detection   总被引:1,自引:0,他引:1  
Molecular methods are useful both to monitor natural communities of bacteria, and to track specific bacterial markers in complex environments. Length-heterogeneity polymerase chain reaction (LH-PCR) and terminal restriction fragment length polymorphism (T-RFLP) of 16S rDNAs discriminate among 16S rRNA genes based on length polymorphisms of their PCR products. With these methods, we developed an alternative indicator that distinguishes the source of fecal pollution in water. We amplify 16S rRNA gene fragments from the fecal anaerobic genus Bacteroides with specific primers. Because Bacteroides normally resides in gut habitats, its presence in water indicates fecal pollution. Molecular detection circumvents the complexities of growing anaerobic bacteria. We identified Bacteroides LH-PCR and T-RFLP ribosomal DNA markers unique to either ruminant or human feces. The same unique fecal markers were recovered from polluted natural waters. We cloned and sequenced the unique markers; marker sequences were used to design specific PCR primers that reliably distinguish human from ruminant sources of fecal contamination. Primers for more species are under development. This approach is more sensitive than fecal coliform assays, is comparable in complexity to standard food safety and public health diagnostic tests, and lends itself to automation and high-throughput. Thus molecular genetic markers for fecal anaerobic bacteria hold promise for monitoring bacterial pollution and water quality.  相似文献   
46.
Survey participants (N=175) were drawn from six branches of a major British supermarket chain. Employees from three branches, who had been selected for transfer to new stores, were surveyed before and after relocation to examine the impact of this transition on individual well‐being. A comparison sample of employees, drawn from similar stores but not involved in relocation, was also surveyed. Cross‐sectional multiple regression analyses found that psychological distress was related to both work demands and personal characteristics (gender, neuroticism, locus of control, and social desirability response). Furthermore, path analysis revealed that after controlling for prior symptom levels, distress during the relocation period was predicted independently by the relocation and by work demands. Although in the present study it was not possible to account for differences in outcomes between new and comparison store employees in terms of changes in measured work characteristics, the negative impact of relocation was found to be buffered by perceptions of control and social support. Additionally, the impact of high work demands was buffered by Type B personal characteristics. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   
47.
Phosphorus (P) runoff from manure can lead to eutrophication of surface water and algae growth. This study evaluates the impacts of alternative P reduction practices on dairy farm net returns and on potential P runoff. The P control practices include dairy herd nutrient management, crop nutrient management, and runoff and erosion control. Four farms representative of dairies in the Virginia Shenandoah Valley are simulated including dairies with and without supplementary broiler enterprises and with average and below average land area. A mathematical programming model was developed to predict farm production and net returns and the GLEAMS model was used to predict potential P runoff. The farms are evaluated under four scenarios: Scenario 1, no constraint on P runoff with access to crop nutrient, runoff and erosion control strategies but no access to dairy herd nutrient control strategies; Scenario 2, no constraint on P runoff with access to all crop and dairy herd nutrient control strategies; Scenario 3, constraint on P runoff with access to crop nutrient, runoff and erosion control strategies but no access to dairy herd nutrient control strategies; and Scenario 4, constraint on P runoff with access to all crop and dairy herd nutrient control strategies. Under Scenario 2, the herd nutrient control strategies increase milk output per cow and net returns on both farms and reduce P content of manure and P runoff. Under Scenario 3, limiting P runoff reduces farm returns by 1 and 3% on the average and small farms, respectively. Under Scenario 4, the P runoff constraint is less costly, reducing returns by less than 1% on both farms. Animal nutrient control strategies should be an important part of pollution control policies and programs for livestock intensive watersheds.  相似文献   
48.
We evaluated the conservation attitudes of the local villagers living adjacent to the Kalakad-Mundanthurai Tiger Reserve in southern India 6 years after implementation of a World Bank funded eco-development project. We assessed attitudes towards three facets of conservation: the tiger, an emblematic species signifying India's commitment to wildlife conservation; the forest, a principle source of fuel-wood and other products; and the Forest Department, which manages the forest. More specifically we predicted that (i) attitudes would be an effective predictor of resource use interest in the forest and (ii) benefits obtained from the EDP would create more favorable attitudes towards conservation and the protected area employees. Twelve villages located within 3 km from the reserve boundary were chosen and 2-3% of the households interviewed with regard to their attitudes towards these three facets of conservation, their household resource use patterns, wealth, sex, age and length of residency. We found significant associations between wealth, sex, age and both tiger and forest conservation. Providing benefits has not changed the underlying attitudes of the communities. The poorer sections of society, whether receiving benefits or not, tended to support tiger conservation because conserving wildlife did not affect their livelihood in any way, whereas both the rich and poor had misgivings about forest conservation due to dependency on forest products. We conclude that the eco-development project has not effectively addressed the most important of the local concerns.  相似文献   
49.
50.
Climate compatible development (CCD) has emerged as a new concept that bridges climate change adaptation, mitigation and community-based development. Progress towards CCD requires multi-stakeholder, multi-sector working and the development of partnerships between actors who may not otherwise have worked together. This creates challenges and opportunities that require careful examination at project and institutional levels and necessitates the sharing of experiences between different settings. In this paper, we draw on the outcomes from a multi-stakeholder workshop held in Mozambique in 2012, the final in a series of activities in a regional project assessing emerging CCD partnerships across southern Africa. The workshop involved policymakers, researchers and representatives from NGOs and the private sector. We employ a content analysis of workshop notes and presentations to identify the progress and challenges in moving four case study countries (the Democratic Republic of the Congo, Mozambique, Zambia and Zimbabwe) towards CCD pathways, by exploring experiences from both project and policy levels. To advance institutional support for the development of successful CCD policies, practices and partnerships, we conclude that there is a need for: (a) institutional development at the national level to strengthen coordination and more clearly define roles and responsibilities across sectors, based on the identification of capacity and knowledge gaps; (b) partnership development, drawing on key strengths and competences of different stakeholders and emphasising the roles of the private sector and traditional authorities; (c) learning and knowledge-sharing through national and regional fora; and (d) development of mechanisms that permit more equitable and transparent distribution of costs and benefits. These factors can facilitate development of multi-stakeholder, multi-level partnerships that are grounded in community engagement from the outset, helping to translate CCD policy statements into on-the-ground action.  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