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   501篇
  免费   7篇
  国内免费   4篇
安全科学   8篇
废物处理   25篇
环保管理   82篇
综合类   56篇
基础理论   77篇
环境理论   1篇
污染及防治   172篇
评价与监测   53篇
社会与环境   33篇
灾害及防治   5篇
  2023年   6篇
  2022年   17篇
  2021年   29篇
  2020年   10篇
  2019年   7篇
  2018年   21篇
  2017年   20篇
  2016年   22篇
  2015年   15篇
  2014年   19篇
  2013年   46篇
  2012年   32篇
  2011年   39篇
  2010年   30篇
  2009年   32篇
  2008年   26篇
  2007年   23篇
  2006年   23篇
  2005年   17篇
  2004年   10篇
  2003年   4篇
  2002年   11篇
  2001年   5篇
  2000年   7篇
  1999年   4篇
  1998年   7篇
  1997年   3篇
  1996年   1篇
  1995年   4篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1989年   2篇
  1987年   1篇
  1985年   1篇
  1984年   2篇
  1982年   1篇
  1981年   5篇
  1980年   3篇
  1979年   1篇
  1978年   1篇
排序方式: 共有512条查询结果,搜索用时 770 毫秒
221.
Wang  Hui  Chen  Zijian  Walker  Tony R.  Wang  Yinggang  Luo  Qing  Wu  Hao  Wang  Xiaoxu 《Environmental geochemistry and health》2022,44(10):3639-3654
Environmental Geochemistry and Health - Characteristics, profile composition, ecological and human health risk of polycyclic aromatic hydrocarbons in surface dust collected from Shenyang city,...  相似文献   
222.
223.
224.
As sustainability considerations increasingly dominate the technology development debate worldwide, practical approaches to assess environmental performance of innovations have been warranted. The present study (Part 1) introduces Ambitec-Life Cycle, a method derived from Ambitec-Agro for considering life cycle thinking in the environmental performance evaluation (EPE) of agro-industrial innovations. An agro-industrial innovation case study related to residue recycling is presented, revealing steps in the product life cycle where opportunities are best for technological improvements. In Part 2 (this issue) of this study, a methodological approach for considering the environmental vulnerability of watersheds and to integrate this analysis in EPE methods is presented. This approach is applied to Ambitec-Life Cycle and to the same residue case study, allowing the identification of performance indicators with greater potential to cause impacts at the studied watersheds.  相似文献   
225.
226.
ABSTRACT: Riparian zones perform a variety of biophysical functions that can be managed to reduce the effects of land use on instream habitat and water quality. However, the functions and human uses of riparian zones vary with biophysical factors such as landform, vegetation, and position along the stream continuum. These variations mean that “one size fits all” approaches to riparian management can be ineffective for reducing land use impacts. Thus riparian management planning at the watershed scale requires a framework that can consider spatial differences in riparian functions and human uses We describe a pilot riparian zone classification developed to provide such a framework for riparian management in two diverse river systems in the Waikato region of New Zealand. Ten classes of riparian zones were identified that differed sufficiently in their biophysical features to require different management. Generic “first steps” and “best practical” riparian management recommendations and associated costs were developed for each riparian class. The classification aims to not only improve our understanding of the effectiveness of riparian zone management as a watershed management tool among water managers and land owners, but to also provide a basis for deciding on management actions.  相似文献   
227.
Pereira Filho, Augusto J., Richard E. Carbone, John E. Janowiak, Phillip Arkin, Robert Joyce, Ricardo Hallak, and Camila G.M. Ramos, 2010. Satellite Rainfall Estimates Over South America – Possible Applicability to the Water Management of Large Watersheds. Journal of the American Water Resources Association (JAWRA) 46(2):344-360. DOI: 10.1111/j.1752-1688.2009.00406.x Abstract: This work analyzes high-resolution precipitation data from satellite-derived rainfall estimates over South America, especially over the Amazon Basin. The goal is to examine whether satellite-derived precipitation estimates can be used in hydrology and in the management of larger watersheds of South America. High spatial-temporal resolution precipitation estimates obtained with the CMORPH method serve this purpose while providing an additional hydrometeorological perspective on the convective regime over South America and its predictability. CMORPH rainfall estimates at 8-km spatial resolution for 2003 and 2004 were compared with available rain gauge measurements at daily, monthly, and yearly accumulation time scales. The results show the correlation between satellite-derived and gauge-measured precipitation increases with accumulation period from daily to monthly, especially during the rainy season. Time-longitude diagrams of CMORPH hourly rainfall show the genesis, strength, longevity, and phase speed of convective systems. Hourly rainfall analyses indicate that convection over the Amazon region is often more organized than previously thought, thus inferring that basin scale predictions of rainfall for hydrological and water management purposes have the potential to become more skillful. Flow estimates based on CMORPH and the rain gauge network are compared to long-term observed average flow. The results suggest this satellite-based rainfall estimation technique has considerable utility. Other statistics for monthly accumulations also suggest CMORPH can be an important source of rainfall information at smaller spatial scales where in situ observations are lacking.  相似文献   
228.
This work reports on an analysis of the cyto- and genotoxicity of poly(lactide-co-glycolide) polymer nanoparticles, in an attempt to evaluate their mutagenic effects. Fibroblast (3T3) and human lymphocyte cell cultures were exposed to solutions containing three different concentrations of nanoparticles (5.4, 54 and 540 μg/mL, polymer mass/volume of solution). The nanoparticles were characterized in terms of their hydrodynamic diameters, zeta potentials and polydispersity indices. The morphology of the particles was determined by atomic force microscopy. The PLGA nanospheres presented a size of 95 nm, a zeta potential of −20 mV and a spherical morphology. Cellular viability assays using fibroblast cells showed no significant alterations compared with the negative control. A cytogenetic analysis of human lymphocyte cells showed no significant changes in the mitotic index in relation to the control, indicating that in the concentration range tested, the particles used in the experimental models did not present cyto- or genotoxicity. For the tests conducted in this work we can conclude that biodegradable and biocompatible PLGA nanospheres are not toxic in the cell cultures tested (fibroblast and lymphocyte cells) and in the range of concentrations employed. The results provide new information concerning the toxic effects of particles produced using PLGA.  相似文献   
229.
Conservation planning tends to focus on protecting species’ ranges or landscape connectivity but seldom both—particularly in the case of diverse taxonomic assemblages and multiple planning goals. Therefore, information on potential trade-offs between maintaining landscape connectivity and achieving other conservation objectives is lacking. We developed an optimization approach to prioritize the maximal protection of species’ ranges, ecosystem types, and forest carbon stocks, while also including habitat connectivity for range-shifting species and dispersal corridors to link protected area. We applied our approach to Sabah, Malaysia, where the state government mandated an increase in protected-area coverage of approximately 305,000 ha but did not specify where new protected areas should be. Compared with a conservation planning approach that did not incorporate the 2 connectivity features, our approach increased the protection of dispersal corridors and elevational connectivity by 13% and 21%, respectively. Coverage of vertebrate and plant species’ ranges and forest types were the same whether connectivity was included or excluded. Our approach protected 2% less forest carbon and 3% less butterfly range than when connectivity features were not included. Hence, the inclusion of connectivity into conservation planning can generate large increases in the protection of landscape connectivity with minimal loss of representation of other conservation targets.  相似文献   
230.
This study aims to show how principal component analysis (PCA) can be used to identify redundant measurements in air quality monitoring networks. The minimum number of air quality monitoring sites in Oporto Metropolitan Area (Oporto-MA) was evaluated using PCA and then compared to the one settled by the legislation. Nine sites, monitoring NO2, O3 and PM10, were selected and the air pollutant concentrations were analysed from January 2003 to December 2005. PCA was applied to the data corresponding to the first two years that were divided into annual quarters to verify the persistence of the PCA results. The number of principal components (PCs) was selected by applying two criteria: Kaiser (PCs with eigenvalues greater than 1) and ODV90 (PCs representing at least 90% of the original data variance). Each pollutant was analysed separately. The two criteria led to different results. Using Kaiser criterion for the eight analysed periods, two PCs were selected in: (i) five periods for O3 and PM10; and (ii) six periods for NO2. These PCs had important contributions of the same groups of monitoring sites. The percentage of the original data variance contained in the selected PCs using this criterion was always below 90%. Thus, the results obtained using ODV90 were considered with more confidence. Using this criterion, only five monitoring sites for NO2, three for O3 and seven for PM10 were needed to characterize the region. The number of monitoring sites for NO2 and O3 was in agreement with what was established by the legislation. However, for PM10, Oporto-MA needed two more monitoring sites. To validate PCA results, statistical models were determined to estimate air pollutant concentrations at removed monitoring sites using the concentrations measured at the remaining monitoring sites. These models were applied to a year's data. The good performance obtained by the models showed that the monitoring sites selected by the procedure presented in this study were enough to infer the air pollutant concentrations in the region defined by the initial monitoring sites. Additionally, the air pollutant analysers corresponding to the redundant measurements can be installed in non-monitored regions, allowing the enlargement of the air quality monitoring 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