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   11913篇
  免费   109篇
  国内免费   89篇
安全科学   336篇
废物处理   443篇
环保管理   1648篇
综合类   2117篇
基础理论   3134篇
环境理论   7篇
污染及防治   2975篇
评价与监测   741篇
社会与环境   625篇
灾害及防治   85篇
  2022年   106篇
  2021年   99篇
  2020年   80篇
  2019年   95篇
  2018年   165篇
  2017年   143篇
  2016年   222篇
  2015年   194篇
  2014年   269篇
  2013年   884篇
  2012年   359篇
  2011年   499篇
  2010年   409篇
  2009年   479篇
  2008年   523篇
  2007年   520篇
  2006年   456篇
  2005年   420篇
  2004年   353篇
  2003年   365篇
  2002年   352篇
  2001年   472篇
  2000年   346篇
  1999年   210篇
  1998年   131篇
  1997年   157篇
  1996年   163篇
  1995年   191篇
  1994年   192篇
  1993年   159篇
  1992年   132篇
  1991年   169篇
  1990年   163篇
  1989年   157篇
  1988年   115篇
  1987年   114篇
  1986年   118篇
  1985年   91篇
  1984年   108篇
  1983年   110篇
  1982年   118篇
  1981年   108篇
  1980年   96篇
  1979年   112篇
  1978年   73篇
  1977年   76篇
  1975年   76篇
  1973年   72篇
  1972年   65篇
  1967年   66篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
401.
In urine-diverting toilets, urine and faeces are collected separately so that nutrient content can be recycled unmixed. Faeces should be sanitized before use in agriculture fields due to the presence of possible enteric pathogens. Composting of human faeces with food waste was evaluated as a possible method for this treatment. Temperatures were monitored in three 78-L wooden compost reactors fed with faeces-to-food waste substrates (F:FW) in wet weight ratios of 1:0, 3:1 and 1:1, which were observed for approximately 20 days. To achieve temperatures higher than 15 degrees C above ambient, insulation was required for the reactors. Use of 25-mm thick styrofoam insulation around the entire exterior of the compost reactors and turning of the compost twice a week resulted in sanitizing temperatures (>or=50 degrees C) to be maintained for 8 days in the F:FW=1:1 compost and for 4 days in the F:FW=3:1 compost. In these composts, a reduction of >3 log(10) for E. coli and >4 log(10) for Enterococcus spp. was achieved. The F:FW=1:0 compost, which did not maintain >or=50 degrees C for a sufficiently long period, was not sanitized, as the counts of E. coli and Enterococcus spp. increased between days 11 and 15. This research provides useful information on the design and operation of family-size compost units for the treatment of source-separated faeces and starchy food residues, most likely available amongst the less affluent rural/urban society in Uganda.  相似文献   
402.
Solid waste management is one of the most challenging issues in urban cities, which are facing a serious pollution problem due to the generation of huge quantities of solid waste. This paper presents an assessment of the existing situation of municipal solid waste management (MSWM) in major cities in India. The quantity and composition of MSW vary from place to place, and bear a rather consistent correlation with the average standard of living. Extensive field investigations were carried out for quantification, analysis of physical composition, and characterization of MSW in each of the identified cities. The MSW management status (per the MSW Rules, 2000) has also been assessed, and an action plan for better management has been formulated; both are presented in this paper. Studies carried out in 59 selected cities in India have revealed that there are many shortcomings in the existing practices used in managing the MSW. These shortcomings pertain mainly to inadequate manpower, financial resources, implements, and machinery required for effectively carrying out various activities for MSWM. To overcome the deficiencies in the existing MSWM systems, an indicative action plan has been presented incorporating strategies and guidelines. Based on this plan, municipal agencies can prepare specific action plans for their respective cities.  相似文献   
403.
Pollution and health risks generated by improper solid waste management are important issues concerning environmental management in developing countries. In most cities, the use of open dumps is common for the disposal of wastes, resulting in soil and water resource contamination by leachate in addition to odors and fires. Solid waste management infrastructure and services in developing countries are far from achieving basic standards in terms of hygiene and efficient collection and disposal. This paper presents an overview of current municipal solid waste management in Rasht city, Gilan Province, Iran, and provides recommendations for system improvement. The collected data of different MSW functional elements were based on data from questionnaires, visual observations of the authors, available reports and several interviews and meetings with responsible persons. Due to an increase in population and changes in lifestyle, the quantity and quality of MSW in Rasht city has changed. Lack of resources, infrastructure, suitable planning, leadership, and public awareness are the main challenges of MSW management of Rasht city. However, the present situation of solid waste management in this city, which generates more than 400tons/d, has been improved since the establishment of an organization responsible only for solid waste management. Source separation of wastes and construction of a composting plant are the two main activities of the Rasht Municipality in recent years.  相似文献   
404.

Introduction

There are many factors that influence older adults' travel choices. This paper explores the associations between mode of travel choice for a short trip and older adults' personal characteristics.

Methods

This study included 406 drivers over the age of 64 who were enrolled in a large integrated health plan in the United States between 1991 and 2001. Bivariate analyses and generalized linear modeling were used to examine associations between choosing to walk or drive and respondents' self-reported general health, physical and functional abilities, and confidence in walking and driving.

Results

Having more confidence in their ability to walk versus drive increased an older adult's likelihood of walking to make a short trip by about 20% (PR = 1.22; 95% CI: 1.06-1.40), and walking for exercise increased the likelihood by about 50% (PR = 1.53; 95% CI = 1.22-1.91). Reporting fair or poor health decreased the likelihood of walking, as did cutting down on the amount of driving due to a physical problem.

Discussion

Factors affecting a person's decision to walk for exercise may not be the same as those that influence their decision to walk as a mode of travel. It is important to understand the barriers to walking for exercise and walking for travel to develop strategies to help older adults meet both their exercise and mobility needs. Impact on Industry: Increasing walking over driving among older adults may require programs that increase confidence in walking and encourage walking for exercise.  相似文献   
405.
Turnover potentially leads to a new individual being selected into a work team. This study investigated the safety-specific trust which team members place in their organisation’s selection and induction processes, and related this to the perceived risk from new employees. The research was conducted with teams working in forest harvesting, an occupation which has high-turnover, high risk and a high accident rate. Results indicate that trust in induction processes was negatively correlated with perceived risk from a new employee. Team members also engaged in a number of safety ensuring behaviours when a new individual joined the team, and these were related to the level of perceived risk, and how much they cared about their team members’ safety. It is argued that trust in the safety-specific characteristics of an organisation’s selection and induction process may have negative consequences for safety.  相似文献   
406.
Sinkings of fishing vessels, when accompanied by human loss, are accidents which lead to a great social upheaval, especially in the local area where they occur. In order to avoid or reduce these accidents, national governments must include in their legislation for this sector the appropriate safety measures. These resources and their distribution must be assigned in accordance with the needs of the accidentality, this requiring a detailed knowledge of the concentration of accidentality of a country’s fishing sector. In this context, the aim of the present work is twofold: first, to formulate a methodology for the fishing sector of a country, allowing the inequalities in the concentration of sinking accidents to be analysed; and second, to apply this methodology to the Spanish fishing fleet. Thus, two indices are constructed per region and type of fishing, for two variables: fishermen and vessels. Results are obtained both for the concentration of accidents and the associated Lorenz curves. An increase in the inequality in the spatial and functional distribution of these accidents is verified.  相似文献   
407.
408.
Jonathan M. H. Green  Gemma R. Cranston  William J. Sutherland  Hannah R. Tranter  Sarah J. Bell  Tim G. Benton  Eva Blixt  Colm Bowe  Sarah Broadley  Andrew Brown  Chris Brown  Neil Burns  David Butler  Hannah Collins  Helen Crowley  Justin DeKoszmovszky  Les G. Firbank  Brett Fulford  Toby A. Gardner  Rosemary S. Hails  Sharla Halvorson  Michael Jack  Ben Kerrison  Lenny S. C. Koh  Steven C. Lang  Emily J. McKenzie  Pablo Monsivais  Timothy O’Riordan  Jeremy Osborn  Stephen Oswald  Emma Price Thomas  David Raffaelli  Belinda Reyers  Jagjit S. Srai  Bernardo B. N. Strassburg  David Webster  Ruth Welters  Gail Whiteman  James Wilsdon  Bhaskar Vira 《Sustainability Science》2017,12(2):319-331
Delivering access to sufficient food, energy and water resources to ensure human wellbeing is a major concern for governments worldwide. However, it is crucial to account for the ‘nexus’ of interactions between these natural resources and the consequent implications for human wellbeing. The private sector has a critical role in driving positive change towards more sustainable nexus management and could reap considerable benefits from collaboration with researchers to devise solutions to some of the foremost sustainability challenges of today. Yet opportunities are missed because the private sector is rarely involved in the formulation of deliverable research priorities. We convened senior research scientists and influential business leaders to collaboratively identify the top forty questions that, if answered, would best help companies understand and manage their food-energy-water-environment nexus dependencies and impacts. Codification of the top order nexus themes highlighted research priorities around development of pragmatic yet credible tools that allow businesses to incorporate nexus interactions into their decision-making; demonstration of the business case for more sustainable nexus management; identification of the most effective levers for behaviour change; and understanding incentives or circumstances that allow individuals and businesses to take a leadership stance. Greater investment in the complex but productive relations between the private sector and research community will create deeper and more meaningful collaboration and cooperation.  相似文献   
409.
Regional Environmental Change - The spatial distribution of forests in Europe represents the legacy of centuries of human land use decisions. Due to the limited availability of historical data,...  相似文献   
410.
In the present context of global change and search for sustainability, we detected a gap between restoration and society: local communities are usually only considered as threats or disturbances when planning for restoration. To bridge this gap, we propose a landscape design framework for planning riparian rehabilitation in an urban–rural gradient. A spatial multi-criteria analysis was used to assess the priority of riversides by considering two rehabilitation objectives simultaneously—socio-environmental and ecological—and two sets of criteria were designed according to these objectives. The assessment made it possible to identify 17 priority sites for riparian rehabilitation that were associated with different conditions along the gradient. The double goal setting enabled a dual consideration of citizens, both as beneficiaries and potential impacts to rehabilitation, and the criteria selected incorporated the multi-dimensional nature of the environment. This approach can potentially be adapted and implemented in any other anthropic–natural interface throughout the world.  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