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   10345篇
  免费   37篇
  国内免费   4篇
安全科学   42篇
废物处理   887篇
环保管理   1324篇
综合类   1038篇
基础理论   3260篇
环境理论   4篇
污染及防治   1844篇
评价与监测   1039篇
社会与环境   935篇
灾害及防治   13篇
  2023年   7篇
  2022年   10篇
  2021年   16篇
  2020年   16篇
  2019年   20篇
  2018年   1493篇
  2017年   1394篇
  2016年   1221篇
  2015年   158篇
  2014年   36篇
  2013年   65篇
  2012年   489篇
  2011年   1381篇
  2010年   725篇
  2009年   639篇
  2008年   910篇
  2007年   1267篇
  2006年   46篇
  2005年   44篇
  2004年   53篇
  2003年   77篇
  2002年   113篇
  2001年   24篇
  2000年   19篇
  1999年   13篇
  1998年   18篇
  1997年   8篇
  1996年   8篇
  1995年   6篇
  1994年   3篇
  1993年   6篇
  1992年   6篇
  1991年   10篇
  1990年   5篇
  1989年   4篇
  1986年   6篇
  1984年   13篇
  1983年   9篇
  1981年   2篇
  1972年   2篇
  1971年   2篇
  1961年   3篇
  1959年   2篇
  1958年   2篇
  1957年   5篇
  1955年   5篇
  1954年   2篇
  1940年   2篇
  1935年   2篇
  1926年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Eero Asmala  Laura Saikku 《Ambio》2010,39(2):126-135
Ongoing eutrophication is changing the Baltic Sea ecosystem. Aquaculture causes relatively small-scale nutrient emissions, but local environmental impact may be considerable. We used substance flow analysis (SFA) to identify and quantify the most significant flows and stocks of nitrogen (N) and phosphorus (P) related to rainbow trout aquaculture in Finland. In 2004–2007, the input of nutrients to the system in the form of fish feed was 829 t N year−1 and 115 t P year−1. Around one-fifth of these nutrients ended up as food for human consumption. Of the primary input, 70% ended up in the Baltic Sea, directly from aquaculture and indirectly through waste management. The nutrient cycle could be closed partially by using local fish instead of imported fish in rainbow trout feed, thus reducing the net load of N and P to a fraction.  相似文献   
952.
953.
The Fallacies of Concurrent Climate Policy Efforts   总被引:1,自引:0,他引:1  
Marian Radetzki 《Ambio》2010,39(3):211-222
Climate policy has assumed an extreme degree of urgency in the international debate in recent years. This article begins by taking a critical look at the scientific underpinnings of the efforts to stabilize the climate. It points to several serious question marks on the purported relationship between greenhouse gas emissions and global warming, and expresses distrust about claims of impending catastrophes related to rising sea levels, hurricanes, and spread of infectious disease. It then reviews the concurrent climate policy efforts and concludes that they are incoherent, misguided and unduly costly, and that they have so far had no perceptible impact on anthropogenic greenhouse gas emissions. The exceedingly ambitious policy plans currently under preparation suffer from similar fallacies. For these reasons, but also because of the remaining scientific doubts and the exorbitant costs that have to be incurred, skepticism is expressed about the preparedness to implement the climate policy plans currently on the table.  相似文献   
954.
955.
Southern Chile encompasses one of the most extensive fjord regions of the world, the Patagonia, currently exposed to natural and anthropogenic perturbations. These fjord ecosystems provide important services to humans, which have not been adequately measured and valued. As a consequence, ecosystem services are commonly ignored in public policy design and in the evaluation of development projects. Here we tackle questions that are highly relevant for the nation’s development, namely (1) understanding fjord functioning, and (2) developing management strategies based on ecosystem services, in order to secure simultaneous and adequate use of these ecosystems which area influenced by ecological (e.g., biogeochemical) and productive (e.g., aquaculture, fisheries) processes. We also seek to strengthen the analysis of fjord ecosystem value from the economical (including coastal zoning), socio-cultural, institutional, and governmental points of view. In addition, the investigation of current and future effects of climate change on this large region offers a unique opportunity to understand the social and economic consequences of a global phenomenon at local to regional scales. Biogeochemical and socio-economic models will be used to simulate future scenarios under a gamut of management options.  相似文献   
956.
During 19–20 October 2009, the Royal Swedish Academy of Sciences arranged the international symposium Energy 2050 in Stockholm. The symposium was held in association with the Swedish EU presidency in autumn 2009. Internationally renowned scientists assessed the energy issue in a broad perspective, with particular emphasis on the possibilities of a fossil-free future. The symposium focused on key topics emanating from the in-depth energy studies carried through by the Academy´s Energy Committee since 2005. The world community is facing a challenge of historic proportions to define a new energy paradigm based on fossil-energy substitutes. This article gives an overview of the current global energy situation (2007) and of the technologies which have the major potential for supplying energy up to year 2050 without jeopardizing the CO2 emission targets.  相似文献   
957.
958.
For many years, the planning and management of terrestrial areas has been supported by a detailed knowledge of the distribution of habitats and their associated species. However, the detailed mapping of biological resources in extent coastal areas, such as the Norwegian coastal zone, is unrealistic due to its enormous coastline. Here, we present a useful and feasible approach and a set of simple, cost-effective methods which are suitable for providing a broad-scale overview of marine habitats and fish resources. This approach was developed in conjunction with a pioneer study conducted along the southern coast of the Skagerrak, where we combined knowledge gathered from local fishermen with scientific knowledge of important species and nature types to establish a coastal sea mapping program. GIS modeling tools were used in both the mapping program and to integrate local and scientific knowledge into digital maps made available to local area management. This multi-faceted approach, which combines local knowledge and scientific methods, provides valuable information with respect to marine biodiversity, and has been used extensively by local environmental management.  相似文献   
959.
Carbon dioxide emissions have accelerated since the signing of the Kyoto Protocol. This discouraging development may partly be blamed on accelerating world growth and on lags in policy instruments. However, it also raises serious question concerning whether policies to reduce CO2 emissions are as effective as generally assumed. In recent years, a considerable number of studies have identified various feedback mechanisms of climate policies that often erode, and occasionally reinforce, their effectiveness. These studies generally focus on a few feedback mechanisms at a time, without capturing the entire effect. Partial accounting of policy feedbacks is common in many climate scenarios. The IPCC, for example, only accounts for direct leakage and rebound effects. This article attempts to map the aggregate effects of different types of climate policy feedback mechanisms in a cohesive framework. Controlling feedback effects is essential if the policy measures are to make any difference on a global level. A general conclusion is that aggregate policy feedback mechanisms tend to make current climate policies much less effective than is generally assumed. In fact, various policy measures involve a definite risk of ‘backfiring’ and actually increasing CO2 emissions. This risk is particularly pronounced once effects of climate policies on the pace of innovation in climate technology are considered. To stand any chance of controlling carbon emissions, it is imperative that feedback mechanisms are integrated into emission scenarios, targets for emission reduction and implementation of climate policy. In many cases, this will reduce the scope for subsidies to renewable energy sources, but increase the scope for other measures such as schemes to return carbon dioxide to the ground and to mitigate emissions of greenhouse gases from wetlands and oceans. A framework that incorporates policy feedback effects necessitates rethinking the design of the national and regional emission targets. This leads us to a new way of formulating emission targets that include feedback effects, the global impact target. Once the full climate policy feedback mechanisms are accounted for, there are probably only three main routes in climate policy that stand a chance of mitigating global warming: (a) returning carbon to the ground, (b) technological leaps in zero-emission energy technology that make it profitable to leave much carbon in the ground even in Annex II countries and (c) international agreements that make it more profitable to leave carbon in the ground or in forests.  相似文献   
960.
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