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   260篇
  免费   5篇
  国内免费   1篇
安全科学   7篇
废物处理   24篇
环保管理   26篇
综合类   43篇
基础理论   33篇
污染及防治   81篇
评价与监测   29篇
社会与环境   23篇
  2023年   10篇
  2022年   22篇
  2021年   19篇
  2020年   7篇
  2019年   13篇
  2018年   17篇
  2017年   12篇
  2016年   19篇
  2015年   10篇
  2014年   5篇
  2013年   16篇
  2012年   18篇
  2011年   20篇
  2010年   5篇
  2009年   8篇
  2008年   6篇
  2007年   8篇
  2006年   7篇
  2005年   12篇
  2004年   2篇
  2003年   8篇
  2002年   4篇
  2001年   4篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1995年   2篇
  1992年   2篇
  1983年   1篇
  1977年   2篇
  1971年   2篇
  1960年   1篇
排序方式: 共有266条查询结果,搜索用时 15 毫秒
81.
Regional Environmental Change - This paper examines barriers and opportunities for climate change adaptation in an urban coastal setting where adaptation is in its infancy. It draws on a diagnostic...  相似文献   
82.
Environmental Science and Pollution Research - Roundup Transorb® (RDT) is a glyphosate-based herbicide commonly used in agricultural practices worldwide. This herbicide exerts negative effects...  相似文献   
83.
84.
Several species of Tenebrionidae are stored-grain pests. Since they belong to a specious family, the systematics of these beetles is still in doubt. In insects, spermatogenesis and the spermatozoa exhibit great diversity, and are therefore commonly used in phylogenetic and taxonomic analyses. During the spermatogenetic process in these organisms, the cells originating from a single spermatogonium develop synchronically in groups referred to as cysts. At the end of this process, there is usually only one sperm bundle per cyst, with all the cells in the same orientation. This paper details the spermiogenesis of the tenebrionid beetles Tenebrio molitor, Zophobas confusa, Tribolium castaneum and Palembus dermestoides using whole mount and histological sections of the cysts. In these species, spermatogenesis is similar to that which occurs in most insects. However, during spermiogenesis, the nuclei of the spermatids migrate to two opposite regions at the periphery of the cyst, leading to the uncommon formation of two bundles of spermatozoa per cyst. This feature is possibly an apomorphy for Tenebrionidae.  相似文献   
85.
Sustainable production and biodiversity conservation can be mutually supportive in providing multiple ecosystem services to farmers and society. This study aimed to determine the contribution of agroforestry systems, as tested by family farmers in the Brazilian Rainforest region since 1993, to tree biodiversity and evaluated farmers’ criteria for tree species selection. In addition, long-term effects on microclimatic temperature conditions for coffee production and chemical and biological soil characteristics at the field scale were compared to full-sun coffee systems. A floristic inventory of 8 agroforests and 4 reference forest sites identified 231 tree species in total. Seventy-eight percent of the tree species found in agroforests were native. The variation in species composition among agroforests contributed to a greater γ-diversity than α-diversity. Monthly average maximum temperatures were approximately 6 °C higher in full-sun coffee than in agroforests and forests. Total soil organic C, N mineralization and soil microbial activity were higher in forests than in coffee systems, whereas the chemical and biological soil quality in agroforests did not differ significantly from full-sun coffee after 13 years. Given its contribution to the conservation of biodiversity and its capacity to adapt coffee production to future climate change, coffee agroforestry offers a promising strategy for the area.  相似文献   
86.
87.
Few systems have been described in which herbivore-induced root volatiles mediate attraction of entomopathogenic nematodes (EPNs), and they only concern root damage inflicted by chewing insects. EPNs, especially Heterorhabditis indica and Steinernema carpocapsae, are potential biological control agents of sugarcane spittlebug (Mahanarva fimbriolata) populations. Here, we investigated the response of these two species of EPNs to sugarcane root volatiles damaged by M. fimbriolata nymphs in a belowground six-arm olfactometer. We also examined changes on root volatile profile in response to herbivory of sugarcane spittlebug nymphs. Results showed that both EPN species did not discriminate between odors of undamaged sugarcane and moistened sand (blank). However, when EPNs were exposed to odors of spittlebug-damaged and undamaged sugarcane roots, both species significantly preferred odors of spittlebug-damaged roots. Headspace collection followed by GC–MS analyses showed no qualitative difference (total of 11 compounds) between volatile profiles of spittlebug-damaged and undamaged sugarcane roots. In contrast to the previous studies involving feeding by root chewing insects, our root volatile analysis did not reveal any up-regulation resulting from sugarcane spittlebug damage, but the down-regulation of the terpenes dihydromyrcenol and β-isomethyl ionone when compared with the profile of undamaged sugarcane roots. Here, we propose alternative explanations for the EPN attraction to spittlebug-damaged roots as it is unlikely that reduced concentrations of the volatiles play a role in this interaction. Further studies are necessary to determine the key compounds of the root volatile emission to enhance biological control efficacy with EPNs against M. fimbriolata in sugarcane.  相似文献   
88.
This work presents a time series strategy for detection, location and quantification of leaks in large pipeline systems. The technology has two active components, which operate sequentially: the Detector and the Localizer. The Detector continuously screens real-time data, searching for any anomalies such as leaks, which are detected (or not) depending on their size and position. The Detector is based on auto-regressive multi-input/multi-output (MIMO) ARX predictors with one input filter. Subsequent to successful leak detection, the Localizer is launched to diagnose the leak via estimation of its parameters – diameter and location – using recorded data on a Search Time Window that includes information in the neighborhood of the instant of detection. The Localizer is also an ARX predictor, but with two input processors, the first is a filter for dynamic plant inputs and the second filter processes “parameter signals” of active leaks. The Localizer is developed beforehand via model identification with plant data under the action of known, artificially simulated, leaks. It is, therefore, able to recognize an active pattern of leak parameters, by maximizing the adherence of its predictions to data in the Search Time Window. The proposed detection and location methods were successfully tested in simulated leak scenarios for an industrial naphtha pipeline.  相似文献   
89.
Environmental Management - Water level variation has an important role in the biology of fish species, driving behavior, feeding, and reproduction both in natural and modified environments. In...  相似文献   
90.
Environmental issues have been at the center of society's concerns for a long time. Recently, this kind of concern is growing even more due to the damage caused to the environment by electrical and electronic product waste. Based on this same concern, this work aimed to analyze, through a literature review, the production and treatment of electronic waste in today's world, with an emphasis on Brazil and China. The articles reviewed point to an increase in the production of this type of waste, in both Brazil and China, and reveal that the current processes of treatment of electronic waste mostly aim to obtain profit through the recovery of precious metals such as copper. This paper concluded that although Brazil is one of the major producers of e‐waste, more than 90% of its e‐waste has not had a proper final destination. This deficiency in e‐waste treatment in Brazil is mainly due to financial factors and the lack of a robust educational policy focused on the environment. Thus, this work suggests the implementation of an effective educational policy aimed at environmental conservation, as well as investments in research on recycling methods in Brazil, especially on the use of e‐waste as an aggregate in the manufacture of concrete.  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