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   908篇
  免费   12篇
  国内免费   11篇
安全科学   39篇
废物处理   32篇
环保管理   207篇
综合类   122篇
基础理论   229篇
环境理论   1篇
污染及防治   203篇
评价与监测   67篇
社会与环境   24篇
灾害及防治   7篇
  2023年   6篇
  2022年   9篇
  2021年   8篇
  2020年   17篇
  2019年   13篇
  2018年   15篇
  2017年   12篇
  2016年   21篇
  2015年   18篇
  2014年   29篇
  2013年   84篇
  2012年   36篇
  2011年   56篇
  2010年   30篇
  2009年   42篇
  2008年   44篇
  2007年   68篇
  2006年   36篇
  2005年   31篇
  2004年   28篇
  2003年   30篇
  2002年   32篇
  2001年   26篇
  2000年   15篇
  1999年   13篇
  1998年   11篇
  1997年   13篇
  1996年   12篇
  1995年   7篇
  1994年   14篇
  1993年   13篇
  1992年   7篇
  1991年   6篇
  1990年   10篇
  1989年   12篇
  1988年   6篇
  1987年   9篇
  1986年   5篇
  1985年   6篇
  1984年   8篇
  1983年   4篇
  1982年   4篇
  1981年   12篇
  1980年   5篇
  1979年   6篇
  1978年   4篇
  1977年   4篇
  1975年   8篇
  1974年   5篇
  1972年   3篇
排序方式: 共有931条查询结果,搜索用时 15 毫秒
211.
Richards SA  Johnson EA 《Ecology》2007,88(6):1582-1586
To study forest dynamics without relying on the space-for-time substitution, one must be able to follow a population or stand of trees back or forward in time. The method of stand reconstruction looks back in time by aging all the live trees and aging and dating the time of death of dead standing and fallen trees. However, dead trees are lost by decomposition so the record becomes increasingly incomplete with passage of time. Here we present a model of the passage of trees from dead standing to dead decomposed but still datable to completely decomposed and thus undatable or lost. We then generalize a method for calculating the falling rate of dead trees originally proposed in 1985 by A. P. Gore, E. A. Johnson, and H. P. Lo. We do this by removing the assumption that no trees are lost by decomposition, i.e., by using the decomposition rate. Finally, in the most important result, the model allows estimation of how far back a good estimate of the numbers in the population can be made if the decomposition rates are known.  相似文献   
212.
Environmental monitoring is increasingly shifting toward a set of systems that describe changes in real time. In ecology specifically, a series of challenges have prevented the rollout of real-time monitoring for features such as biodiversity change or ecosystem service provision. Conservation culturomics, a field concerned with interactions between people and nature, is well placed to demonstrate how monitoring might move toward a network of real-time platforms, given its existence exclusively in the digital realm. We examined a set of considerations associated with the development of real-time monitoring platforms for conservation culturomics and introduce a near real-time platform for the Species Awareness Index, a global index of changing biodiversity awareness derived from the rate of change in page views for species on Wikipedia. This platform will update automatically each month, operating in near real time ( https://joemillard.shinyapps.io/Real_time_SAI/ ). There are plans to make the underlying data queryable via an application programing interface independent of the platform. The real-time Species Awareness Index will represent the first real-time and entirely automated conservation culturomic platform and one of the first real-time platforms in the discipline of ecology. Real-time monitoring for culturomics can provide insight into human–nature interactions as they play out in the physical realm and provide a framework for the development of real-time monitoring in ecology. Real-time monitoring metrics can be processed on private virtual machines and hosted on publicly available cloud services. Conservation now needs an online, real-time observatory that can evolve with the structure of the web.  相似文献   
213.
Infectious disease surveillance has become an international top priority due to the perceived risk of bioterrorism. This is driving the improvement of real-time geo-spatial surveillance systems for monitoring disease indicators, which is expected to have many benefits beyond detecting a bioterror event. West Nile Virus surveillance in New York State (USA) is highlighted as a working system that uses dead American Crows (Corvus brachyrhynchos) to prospectively indicate viral activity prior to human onset. A cross-disciplinary review is then presented to argue that this system, and infectious disease surveillance in general, can be improved by complementing spatial cluster detection of an outcome variable with predictive “risk mapping” that incorporates spatiotemporal data on the environment, climate and human population through the flexible class of generalized linear mixed models.
Glen D. JohnsonEmail:
  相似文献   
214.
215.
216.
217.
218.
219.
220.
Innovative cities are essential for the economic growth and development of countries. At the same time, however, social and environmental problems related to city growth can be serious threats to the full realisation of the socio-economic contribution that cities can make. City environments thus often provide both new problems and the creative and diverse environments, which make it possible to solve them. The question of whether or not sustainable development is possible largely will be answered in cities. This is also the case for problems related to waste management. Landfills may be located in the countryside, but if a country is to reduce environmental costs, the results will rest on the innovation power of cities. In this paper it is argued that the notion of a 'system of innovation' is helpful in understanding the factors that shape the processes of innovation and that determine the extent to which environmental problems may be solved. In this context, institutional innovation and political innovation as compared to technical innovation are of special importance.  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