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   278篇
  免费   0篇
安全科学   2篇
废物处理   6篇
环保管理   8篇
综合类   125篇
基础理论   45篇
污染及防治   67篇
评价与监测   11篇
社会与环境   12篇
灾害及防治   2篇
  2021年   3篇
  2018年   8篇
  2017年   4篇
  2015年   7篇
  2014年   13篇
  2013年   7篇
  2012年   6篇
  2011年   5篇
  2010年   13篇
  2009年   12篇
  2008年   8篇
  2007年   9篇
  2006年   8篇
  2005年   7篇
  2004年   6篇
  2003年   8篇
  2002年   6篇
  1998年   7篇
  1996年   7篇
  1995年   3篇
  1993年   4篇
  1979年   2篇
  1971年   2篇
  1969年   2篇
  1966年   3篇
  1965年   5篇
  1964年   2篇
  1963年   7篇
  1962年   4篇
  1961年   3篇
  1960年   2篇
  1959年   5篇
  1958年   5篇
  1957年   3篇
  1956年   10篇
  1955年   7篇
  1954年   3篇
  1953年   3篇
  1952年   2篇
  1950年   2篇
  1949年   2篇
  1947年   2篇
  1942年   2篇
  1940年   2篇
  1939年   4篇
  1934年   3篇
  1933年   2篇
  1929年   2篇
  1925年   2篇
  1918年   2篇
排序方式: 共有278条查询结果,搜索用时 15 毫秒
191.
Regional Environmental Change - This article describes the design of a new model-based assessment framework to identify and analyse possible future trajectories of agricultural development and...  相似文献   
192.
A new unstructured mesh coastal water and air quality model has been developed that includes species transport, nonlinear decay, by-product formation, and mass-exchange between sea and atmosphere. The model has been programmed with a graphical user interface and is applicable to coastal seawater, lakes, and rivers. Focused on species conversion and interaction with the atmosphere, the water and air quality model follows a modular approach. It is a compatible module which simulates distributions based on fluid dynamic field data of underlying existing hydrodynamic and atmospheric simulations. Nonlinear and spline approximations of decay and growth kinetics, by-product formation, and joint sea–atmosphere simulation have been embedded. The Windows application software includes functions allowing error analysis concerning mesh and finite volume approximation. In this work, a submerged residual chlorine cooling water discharge and halogenated matter by-product formation has been simulated. An error analysis has been carried out by varying vertical meshing, time-steps and comparing results based on explicit and implicit finite volume approximation. The new model has been named 3D Simulation for Marine and Atmospheric Reactive Transport, in short 3D SMART.  相似文献   
193.
Environmental Science and Pollution Research - Historical industrial activities at the Horn Richterwil, on the shore of Lake Zurich (Switzerland), caused widespread metal contamination on land and...  相似文献   
194.
Ozone (O3) fluxes above a temperate mountain grassland were measured by means of the eddy covariance (EC) method using a slow-response O3 analyser. The resultant flux loss was corrected for by a series of transfer functions which model the various sources of high- and, in particular, low-pass filtering. The resulting correction factors varied on average between 1.7 and 3.5 during night and daytime, respectively. A cospectral analysis confirmed the accuracy of this approach. O3 fluxes were characterised by a comparatively large random uncertainty, which during daytime typically amounted to 60%. EC O3 fluxes were compared against O3 flux measurements made concurrently with the flux-gradient (FG) method. The two methods generally agreed well, except for a period between sunrise and early afternoon, when the FG method was suspected of being affected by the presence of photochemical sources/sinks. O3 flux magnitudes and deposition velocities determined with the EC method compared nicely with the available literature from grassland studies. We conclude that our understanding of the causes and consequences of various sources of flux loss (associated with any EC system) has sufficiently matured so that also less-than-ideal instrumentation may be used in EC flux applications, albeit at the cost of relatively large empirical corrections.  相似文献   
195.
The pHstat-procedure is a method to examine the pH-dependent mobilisation of heavy metals and other pollutants from solids. The metals in such extracts are usually determined by atomic absorption (AAS) or by emission spectrometry (ICP-OES). The obtained values present the total amount of mobilized metals. A statement concerning the effect-oriented true toxicity of the extract, respective of the examined solid, is not possible. A combined effect-oriented procedure, such as a the bioaluminescence-inhibition test with luminescence bacteria enables a precise statement about the ecotoxicity of solids. A variation of the inhibition test (addition of EDTA) indicates the main binding forms of heavy metals and the part of inhibition caused by organic material.  相似文献   
196.
197.
Marine protected areas (MPAs) are attaining increasing importance in the management of marine ecosystems. They are effective for conservation in tropical and subtropical areas (mainly coral and rocky reefs), but it is debated whether they are useful in the management of migratory fish stocks in open temperate regions. World War II created a large marine area within which commercial fishing was prevented for 6 years. Here we analyse scientific trawl data for three important North Sea gadoids, collected between 1928 and 1958. Using statistical models to summarise the data, we demonstrate the potential of MPAs for expediting the recovery of over-exploited fisheries in open temperate regions. Our age-structured data and population models suggest that wild fish stocks will respond rapidly and positively to reductions in harvesting rates and that the numbers of older fish in a population will react before, and in much greater proportion, than their younger counterparts in a kind of Mexican wave. Our analyses demonstrate both the overall increase in survival due to the lack of harvesting in the War and the form of the age-dependent wave in numbers. We conclude that large closed areas can be very useful in the conservation of migratory species from temperate areas and that older fish benefit fastest and in greater proportion. Importantly, any rise in spawning stock biomass may also not immediately result in better recruitment, which can respond more slowly and hence take longer to contribute to higher future harvestable biomass levels.  相似文献   
198.
199.
Regional Environmental Change - Land use and spatial patterns which reflect social-ecological legacies control ecosystem service (ES) supply. Yet, temporal changes in ES bundles associated with...  相似文献   
200.
Abstract

The National Oceanic and Atmospheric Administration recently sponsored the New England Forecasting Pilot Program to serve as a “test bed” for chemical forecasting by providing all of the elements of a National Air Quality Forecasting System, including the development and implementation of an evaluation protocol. This Pilot Program enlisted three regional-scale air quality models, serving as prototypes, to forecast ozone (O3) concentrations across the northeastern United States during the summer of 2002. A suite of statistical metrics was identified as part of the protocol that facilitated evaluation of both discrete forecasts (observed versus modeled concentrations) and categorical forecasts (observed versus modeled exceedances/nonexceedances) for both the maximum 1-hr (125 ppb) and 8-hr (85 ppb) forecasts produced by each of the models. Implementation of the evaluation protocol took place during a 25-day period (August 5–29), utilizing hourly O3 concentration data obtained from over 450 monitors from the U.S. Environment Protection Agency’s Air Quality System network.  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