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   133篇
  免费   1篇
  国内免费   3篇
安全科学   1篇
废物处理   5篇
环保管理   10篇
综合类   12篇
基础理论   51篇
污染及防治   38篇
评价与监测   15篇
社会与环境   5篇
  2023年   2篇
  2022年   6篇
  2021年   2篇
  2018年   9篇
  2017年   5篇
  2016年   4篇
  2015年   2篇
  2014年   3篇
  2013年   21篇
  2012年   11篇
  2011年   6篇
  2010年   8篇
  2009年   7篇
  2008年   5篇
  2007年   7篇
  2006年   3篇
  2005年   7篇
  2004年   10篇
  2003年   3篇
  2002年   2篇
  2001年   4篇
  2000年   3篇
  1999年   1篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
  1984年   1篇
排序方式: 共有137条查询结果,搜索用时 15 毫秒
101.
From 1994 to 2003, daily air concentrations of particle-bound polycyclic aromatic hydrocarbons (PAHs) and carbon monoxide (CO) were regularly monitored at two traffic-oriented sampling sites (A and B) in urban Genoa, Italy. The data were used to estimate effects on air quality in real situations due to progressive substitution of EURO-0 vehicles, started in 1993, with less-polluting vehicles (EURO-1, EURO-2), mainly gasoline vehicles with a catalyst. PAH profile classification and diagnostic PAH ratios were used to identify 345 samples of predominantly traffic origin. At both sites, CO and PAH daily concentrations decreased exponentially with time and the apparent half-life values calculated were 6.3 and 5.5 for CO and 3.7 and 3.5 years for PAHs at sites A and B, respectively. At site A, monitored for traffic intensity, multiple regression analyses confirmed that daily PAH and CO concentrations were positively correlated with the number of non-catalytic vehicles estimated to cross this site during sampling and negatively correlated with seasonal variables (air temperature, ozone concentration, relative air humidity). The reduction in air pollution estimated for complete substitution of non-catalytic gasoline vehicles was 89% for BaP, 85% for total PAHs and 69% for CO.  相似文献   
102.
Some flint lithic artifacts were discovered in the fissure fillings of the well-known Pirro Nord site (Apulia, Southern Italy). The lithic industry, composed by three cores and some flakes, has been found to be associated to an Early Pleistocene vertebrate fossil assemblage. The fossil association contains a wide range of micromammals, including Allophaiomys ruffoi and Episoriculus gibberodon and large mammals including Bison degiulii and Equus altidens together with African elements as the gelada baboon Theropithecus and the saber-toothed cat Megantereon whitei. It defines the latest Villafranchian chronological unit (Pirro Nord Faunal Unit) in the Western European mammal biochronology. The lithic industry of Pirro Nord represents the oldest occurrence of the genus Homo in Europe as it is attributable to a chronological interval between 1.3 and 1.7 Ma. This supports the hypothesis that the genus Homo, with Oldowaian technology, extended its range in Europe, probably from western Asia, during the first half of the Early Pleistocene. The new discovery from Pirro Nord changes the chronology of the first arrival of hominids in Europe and offers new perspectives in the debate about the human dispersal in the Early Pleistocene.  相似文献   
103.
104.
The courtship and mounting behaviour of tortoises is elaborate, and based on a multiple signalling system involving visual, olfactory and acoustic signals. Vocalizations related to mounting seem to be particularly significant because tortoises vocalize mainly at this time. Vocalizations and courtship behaviour may be costly for males, and if these costs increase differentially for different males, then the potential exists for vocalizations and displays to reveal male individual quality. In this correlative study, we analysed relationships between male mounting success and morphological and behavioural traits, particularly acoustic signals, exhibited by male marginated tortoises (Testudo marginata) during courtship, in a group of 94 individuals breeding in semi-natural enclosures. For each male, we estimated general body condition, courtship intensity and mounting success; calls of mounting males were recorded and four sonagraphic features were measured. Calls differed significantly among males, and two features varied according to body condition. Male mounting success significantly increased according to the male/female size-ratio, suggesting the existence of a size-based assortative mating. Mounting success was also highly correlated with courtship intensity, measured as number of bites and rams given to females before mounting, and with number of calls emitted during mounting. Finally, mounting success was negatively related to call duration. To our knowledge, this is the first study in which features of tortoise vocalizations are shown to convey reliable information about male quality in socio-sexual contexts.Communicated by T. Czeschlik  相似文献   
105.
106.
Non-random sex allocation may occur whenever the expected reproductive value of sons and daughters differs, as is the case when the sexes differ in susceptibility to environmental conditions or maternal effects (e.g. egg size and hatch order). Under such circumstances, covariation between egg and clutch characteristics and egg sex may be expected, and this covariation should vary with maternal state or ecological conditions. In this 2-year study (2007–2008), we examined sex allocation in relation to egg and clutch traits in the yellow-legged gull Larus michahellis, a species where male chicks are larger and more susceptible to harsh rearing conditions than female ones. In 2008, eggs were more likely male early in the season in two- but not three-egg clutches, and large eggs were more likely males late in the season. No egg/clutch traits predicted egg sex in 2007. Within-clutch egg mass asymmetry (the difference in egg mass between the first- and last-laid eggs) predicted sex in both years. In 2007, clutches with smaller egg mass variation were more likely to contain males, while in 2008 this relationship held for the last-laid egg and was reversed for the preceding egg(s). Laying order and sex of the previous egg did not predict egg sex, providing no evidence of sex-specific oocyte clustering. Thus, the relationships between egg sex and egg/clutch traits differed among years, suggesting a phenotypically plastic response of females to extrinsic conditions, and involved within-clutch egg mass asymmetry, a trait likely reflecting variation in maternal quality and/or reproductive tactics, which has been largely neglected in previous studies of sex allocation.  相似文献   
107.

Introduction  

In this work, we propose an innovative application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) as a methodological approach for the chemical characterisation of black crusts on stone monuments, associated with traditional micro-morphological (optical and scanning electron microscopy) and infrared spectroscopic techniques (FTIR).  相似文献   
108.
We analyze the invisibility of fisheries and inadequacy of fishers’ participation in the process of hydropower development in the Amazon, focusing on gaps between legally mandated and actual outcomes. Using Ostrom’s institutional design principles for assessing common-pool resource management, we selected five case studies from Brazilian Amazonian watersheds to conduct an exploratory comparative case-study analysis. We identify similar problems across basins, including deficiencies in the dam licensing process; critical data gaps; inadequate stakeholder participation; violation of human rights; neglect of fishers’ knowledge; lack of organization and representation by fishers’ groups; and lack of governmental structure and capacity to manage dam construction activities or support fishers after dam construction. Fishers have generally been marginalized or excluded from decision-making regarding planning, construction, mitigation, compensation, and monitoring of the social–ecological impacts of hydroelectric dams. Addressing these deficiencies will require concerted investments and efforts by dam developers, government agencies and civil society, and the promotion of inter-sectorial dialogue and cross-scale participatory planning and decision-making that includes fishers and their associations.  相似文献   
109.
110.
This research proposes an integrated framework to investigate human-dominated systems and provide a basic approach to urban and regional studies in which the multiple interactions between economic and ecological processes are considered as a whole. Humans generate patterns of land use, infrastructures and other settings and redistribute ecosystem functions as flows of energy and matter for self-maintenance. To understand these emerging interactions between humans and ecological processes, human activities (e.g. transformation processes, land conversions, use of resources) and biophysical agents such as geomorphology, climate and natural cycles need to be considered. Emergy Analysis (spelled with an “m”) is then used as an environmental accounting method to evaluate different categories of resource use with reference to their environmental cost. A case study of the Province of Cagliari (in the island of Sardinia, Italy) is reported and the procedure for allocating emergy flows, assigning them to districts and managing point data is discussed. Outcomes plotted on a map showed non-homogeneous spatial distribution of emergy flows throughout the region, suggesting the way ecosystem functions are affected and restructured by the human economy.  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