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   284篇
  免费   15篇
  国内免费   17篇
安全科学   12篇
环保管理   121篇
综合类   44篇
基础理论   119篇
污染及防治   7篇
评价与监测   3篇
社会与环境   2篇
灾害及防治   8篇
  2023年   5篇
  2022年   1篇
  2021年   2篇
  2020年   4篇
  2019年   75篇
  2018年   5篇
  2017年   3篇
  2016年   6篇
  2015年   6篇
  2014年   15篇
  2013年   38篇
  2012年   33篇
  2011年   32篇
  2010年   22篇
  2009年   5篇
  2008年   19篇
  2007年   8篇
  2006年   11篇
  2005年   2篇
  2004年   6篇
  2003年   2篇
  2002年   2篇
  2001年   1篇
  2000年   3篇
  1999年   1篇
  1998年   2篇
  1996年   1篇
  1995年   2篇
  1993年   2篇
  1991年   1篇
  1973年   1篇
排序方式: 共有316条查询结果,搜索用时 203 毫秒
131.
介绍了一种基于AVR单片机的一种Internet联网智能安防报警主机的硬件及软件设计。安防报警主机以AVR系列的ATmega16单片机为控制核心,以ENC28J60作为Internet接口的以太网控制器控制芯片,当布防区域有警情或报警主机有异常发生时,可以即时通过Internet对预先设定报警服务主机进行报警。通过Internet,用户可以随时随地通过PC控制主机对远端报警主机进行布防、撤防及查询状态等控制。本报警主机具有组网方便、监测范围广、报警可靠性高等特点。  相似文献   
132.
Vlado Vivoda   《Resources Policy》2011,36(1):49-59
The aim of this paper is to assess the conditions that influence foreign direct investment in the mineral industries of China and India. The paper first surveys literature on the determinants of foreign direct investment to identify key conditions, under which host countries attract mining FDI. It then builds an evaluative framework which allows for comparative analysis. The paper then comparatively evaluates the performance of foreign investment regimes that govern mineral industries in China and India. Its findings show that the overall conditions for foreign mining investment in China and India are not favourable and that substantial policy, regulatory and other changes in both countries need to be made if more investment is to flow.  相似文献   
133.
Modelling ecological or environmental problems has potential to provide understanding of the causes of such problems and to indicate how to better manage them. Özesmi and Özesmi (2004) showed that cognitive or causal mapping can be used to develop maps of socio-ecological systems but these maps were based on stakeholders concerned with one ecosystem. This article shows how maps from a number of different dairy farmers in different locations, but each considering his or her own farm, can be used in meta analysis to make maps that represent how farmers think their farm ecosystem works. It also shows that the combination of causal mapping with the additional technique of Q method provides a useful solution to the practical problem of selecting from a sufficiently broad range of factors with potential to use in a map. Causal mapping in single or multiple locations contributes to the goal of using peoples’ knowledge of ecosystems to improve our understanding of socio-ecological systems.  相似文献   
134.
Two kinds of disparities pervade China and threaten its well-being. The first, regional disparities focus on levels of economic development, which vary considerably across China. The second is largely a corollary of the first, referring to mismatch in energy supply and demand, with some places suffering severe shortages while others are blessed with significant surpluses. Western China enjoys the dubious distinction of recording the country's lowest levels of economic development while, paradoxically, being blessed with plentiful reserves of energy and non-energy minerals. Turning those surplus resources to good account through transferring them to minerals and energy-hungry Eastern China is seen by policy-makers as something of a panacea. Not only will such a strategy significantly boost Western China's economic prospects, but it will eliminate the resource shortages currently constraining the East's vibrant growth. The issues of regional disparities, energy mismatches and transfers of these resources are discussed, with attention given to both spatial and time perspectives. The paper concludes with a cautious endorsement of the policy initiatives that promote the strategy of mineral transfers.  相似文献   
135.
According to Pindyck (2007) there are three important aspects of uncertainly in environmental economics: (1) the benefits and costs of environmental policy tend to be highly non-linear, (2) environmental policy tends to involve important irreversibilities, where investment in pollution abatement can impose an irreversible, sunk cost on society, and where certain pollutants can stay in the environment forever and build up to cause even more future harm in which case investment in abatement can cause an irreversible, sunk benefit to society, and (3) environmental policy involves long time horizons and yet the discount rate society should use is uncertain for determining the net present value of costs and benefits of pollution abatement. These same uncertainties also affect non-renewable, exhaustible, natural resource economics and in particular the use of the Hotelling rule: (1) the costs, benefits and transversality conditions of using the Hotelling rule can be highly non-linear, (2) the Hotelling rule involves important sunk cost irreversibilities, which will be explained here, and (3) the Hotelling rule can involve long time horizons with uncertain discount rates. All three of these problem make it extremely difficult for a market to use in any way the Hotelling rule, yet by the sheer number of articles in non-renewable natural resource economics, one would believe that it is the basis of all resource markets. In this article, we concentrate on the sunk cost irreversibilities of using the Hotelling rule. The idea of the Hotelling rule is to optimally store a non-renewable resource, but the optimization is highly dependent on the actual reserves that are available to extract. However, reserves of underground exhaustible resources are often unobservable at the beginning stages of extraction which makes using the Hotelling Rule difficult.  相似文献   
136.
Supply of some critical raw materials by European industry is becoming more and more difficult. After the case of natural textile fibres, in particular cotton, and timber, over the last few years the problem of rare earths (REs) availability has also risen. The 97% of the global supply of rare earth metals (REMs) is produced by China, that has recently done copious cuts of its exports, apparently in order to protect its environment. This fact has greatly increased the REs prices, causing tension and uncertainty among the world hi-tech markets. Many of these materials, in fact, have very few effective substitutes and low recycling rates too. In addition, their natural reserves of rare earths are concentrated in a small number of countries (China, Brazil, US, Russia, Democratic Republic of Congo). REMs are a group of 17 elements particularly used in many new electronic and advanced components: such as fuel cells, mobile phones, displays, hi-capacity batteries, permanent magnets for wind power generation, green energy devices, etc. Many analysts foresee much more requests in the next decades.  相似文献   
137.
There are frequent suggestions that countries specializing in mineral and energy extraction have a type of growth that is bad for the poor. Others claim that extraction-led growth is particularly good for the poor. Both claims are made without the support of substantial empirical evidence. This paper uses longitudinal data on income growth by quintile in 57 developed and developing countries to statistically assess how mineral and energy extraction has affected the relationship between growth and the poor. We can find no evidence that the data support either the claim that extraction-led growth is good for the poor or that extraction-led growth is bad for the poor. This finding does not rule out that extractive activity can have special positive or negative impacts on the poor in some countries or regions. Rather, it simply brings to light that such effects are not evident as a persistent statistical phenomenon in the national level data that are available, which may be why the debate tends to move along without resolution.  相似文献   
138.
Fuel and leasable minerals mined in the United States have historically been subject to federal royalties while locatable minerals have not. In recent years there have been multiple attempts to alter this policy and subject locatable minerals to federal royalties as well; most recently the preliminary 2012 Obama budget included a gross royalty on hard-rock mining on public lands. This paper analyzes the issue of imposing such federal royalties from both a legal and economic perspective. From a legal perspective, it is argued that the state of western property rights precludes royalties on currently extant claims so revenues from a royalty would not be realized for many years. From an economic perspective, it is argued that the effect on revenue would be smaller than one might anticipate due to such a royalty crowding out state levies or encouraging vertical disintegration on the part of mining firms to avoid much of the burden of the royalty.  相似文献   
139.
The social and environmental impacts of rapidly expanding coal and gas industries have generated high levels of public concern and there is increasing evidence of cumulative impacts. In the Bowen Basin of Queensland (Australia) water quality issues have triggered a collaborative response to coordinate monitoring efforts, integrate data and information and undertake regional analysis to inform landscape-scale management. Collaborative governance is promoted as a response to complex environmental problems, such as cumulative impacts. However, application of this approach to the resources and energy sectors remains a significant research gap. This paper reports the results of action research in the 2 years taken to negotiate the establishment of collaborative governance arrangements to address mine-water discharge impacts in the Bowen Basin. The long establishment phase has been required to refine objectives, build trust, develop governance mechanisms and secure resourcing commitments. The partnership established involves more than 20 organisations including regulators, resources and energy companies, agricultural industries and research organisations. The breadth of participating sectors is a significant innovation, but also represents a major challenge in establishing this model of regional environmental governance. Promising strategies adopted to manage these tensions have included neutral brokerage, facilitative leadership, establishing legitimacy of the collaboration and credibility of its reports. The case study provides a cautionary tale of the pursuit of the promise of ‘everyone working together’ to address cumulative impacts. Policy implications include the need for extended commitment and integration of collaborative and other responses.  相似文献   
140.
Platinum is increasingly used intentionally and non-intentionally in several applications. This has raised the concern about its future resources, emissions and losses during its life cycle. On the one hand, increasing platinum emissions might affect human health. On the other hand, the accumulated platinum in mineral waste, soil, landfill sites and construction materials as a result of the emissions, losses and the utilization of secondary materials can be seen as potential resources for platinum. This paper is aimed at (1) analyzing the long term impacts of the use of platinum intentionally and non-intentionally on its future demand and supply, release to the environment and accumulation in mineral waste, soil, landfill sites and construction materials and (2) quantifying the amount of platinum in secondary materials that would be available for platinum future supply. The analysis is carried out on a global level using a system dynamic model of platinum intentional and non-intentional flows and stocks. The analysis is based on four scenarios for the introduction of fuel cell vehicles (FCVs). The results show that platinum demand is increasing overtime in all scenarios at different rates and its identified resources are expected to deplete before the end of the century with or without the introduction of FCVs. The release of platinum to the environment and the accumulation in soil are expected to decrease when conventional ICE vehicles is replaced by FCVs. The amount of platinum accumulated in mineral waste, soil, landfill sites and construction materials by the time platinum is depleted are more than double its identified resources and would be potential resources for platinum that are available in different parts of the world. The methodology presented in this paper can be used in the assessment of other technologies and other metals.  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