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   385篇
  免费   22篇
  国内免费   5篇
安全科学   37篇
废物处理   10篇
环保管理   97篇
综合类   44篇
基础理论   124篇
环境理论   2篇
污染及防治   51篇
评价与监测   26篇
社会与环境   16篇
灾害及防治   5篇
  2023年   9篇
  2022年   4篇
  2021年   8篇
  2020年   14篇
  2019年   11篇
  2018年   21篇
  2017年   15篇
  2016年   26篇
  2015年   19篇
  2014年   17篇
  2013年   28篇
  2012年   35篇
  2011年   26篇
  2010年   14篇
  2009年   27篇
  2008年   22篇
  2007年   20篇
  2006年   21篇
  2005年   13篇
  2004年   7篇
  2003年   10篇
  2002年   8篇
  2001年   3篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1996年   4篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1986年   1篇
  1985年   1篇
  1982年   1篇
  1981年   5篇
  1980年   5篇
  1977年   2篇
  1976年   1篇
  1975年   1篇
  1970年   1篇
排序方式: 共有412条查询结果,搜索用时 31 毫秒
201.
202.
203.
204.
205.

Objective

This study explored the care experiences of parents whose pregnancy was diagnosed with a fatal fetal anomaly following the legalisation of termination of pregnancy in 2019 in Ireland.

Methods

A qualitative study using in-depth semi-structured interviews and interpretative phenomenological analysis was undertaken. Purposeful sampling was used to recruit 10 parents, six women and four of their male partners. Parents recruited included those who terminated and continued the pregnancy.

Results

Three superordinate themes were identified: ‘Attachment and coping’, ‘There's no place for you in the pregnancy world’ and ‘Consistency of quality care’. Parents shared the different approaches and level of attachment to their baby that supported their coping. Regardless of the level of attachment, many parents benefited from the acts of remembrance. Parents expressed how they no longer felt they belonged in the ‘pregnancy world’ and described a need for healthcare professionals to recognise their loss and create a safe and supportive environment in which they could share their grief. Despite this, parents' accounts highlighted variations and inconsistencies in care and service provision.

Conclusion

Our study highlighted parents' need for consistent, well communicated, and comprehensive care, which encourages an individualised perinatal palliative care approach to meet parental needs.  相似文献   
206.
Regional Environmental Change - Mountain forests provide a wide range of ecosystem services (ES, e.g., timber production, protection from natural hazards, maintaining biodiversity) and are...  相似文献   
207.
Montgomery RA  Reich PB  Palik BJ 《Ecology》2010,91(12):3641-3655
In ecological communities, the outcome of plant-plant interactions represents the net effect of positive and negative interactions occurring above and below ground. Untangling these complex relationships can provide a better understanding of mechanisms that underlie plant-plant interactions and enhance our ability to predict population, community, and ecosystem effects of biotic interactions. In forested ecosystems, tree seedlings interact with established vegetation, but the mechanisms and outcomes of these interactions are not well understood. To explore such mechanisms, we manipulated above- and belowground interactions among tree seedlings, shrubs, and trees and monitored seedling survival and growth of six species (Pinus banksiana, Betula papyrifera, P. resinosa, Quercus rubra, P. strobus, and Acer rubrum) in mature pine-dominated forest in northern Minnesota, USA. The forest had a moderately open canopy and sandy soils. Understory manipulations were implemented in the forest interior and in large gaps and included removal of shrubs (no interactions), tieback of shrubs (belowground), removal of shrubs with addition of shade (aboveground), and unmanipulated shrubs (both below- and aboveground). We found that shrubs either suppressed or facilitated seedling survival and growth depending on the seedling species, source of interaction (e.g., above- or belowground), and ecological context (e.g., gap or forest interior). In general, shrubs strongly influenced survival and growth in gaps, with more modest effects in the forest interior. In gaps, the presence of shrub roots markedly decreased seedling growth and survival, supporting the idea that belowground competition may be more important in dry, nutrient-poor sites. Shrub shade effects were neutral for three species and facilitative for the other three. Facilitation was more likely for shade-tolerant species. In the forest interior, shrub shade negatively affected seedling survival for the most shade-intolerant species. For several species the net effect of shrubs masked the existence of both positive and negative interactions above and below ground. Our results highlight the complexity of plant-plant interactions, demonstrate that outcomes of these interactions vary with the nature of resource limitation and the ecophysiology of the species involved, and suggest that ecological theory that rests on particular notions of plant-plant interactions (e.g., competition) should consider simultaneous positive and negative interactions occurring above and below ground.  相似文献   
208.
Individuals under stress and those of intrinsically low quality may have insufficient resources to invest in developing equally on both sides. Such individuals may thus display higher levels of fluctuating asymmetry (FA)—small, random departures from perfect bilateral symmetry. These small deviations from symmetry are often less than 1 % of trait size, similar to variation in symmetry generated by measurement error. Studies regarding FA must thoroughly assess measurement error if reliable conclusions regarding FA and fitness parameters are to be drawn. Although many studies regarding facial symmetry in humans have been conducted, few have been carried out on non-human primates. The primary aim of this study was to assess whether facial FA in a non-human primate, the olive baboon (Papio anubis) can be reliably measured from digital photographs. Facial FA was measured in three sets of bilaterally symmetrical landmarks from digital images of 35 olive baboons at Gashaka-Gumti National Park, Nigeria. Measurement error was found to be low indicating a high level of reliability based on comparisons of values from two photos of the same individual (r?=?0.85). Measurement error was found to be related to the size of the face. This suggests that orientation error increases in large faces and could potentially influence FA scores. These findings highlight the need for FA studies to measure and control error caused by orientation and position of subjects if FA is to be of utility to behavioural ecology and conservation (e.g. if FA reflects whether individuals in a population are suffering from environmental or genetic stress).  相似文献   
209.
The use of signals across multiple sensory modalities in communication is common in animals and plants. Determining the information that each signal component conveys has provided unique insights into why multimodal signals evolve. However, how these complex signals are assessed by receivers will also influence their evolution, a hypothesis that has received less attention. Here, we explore multimodal signal assessment in a closely related complex of island flycatchers that have diverged in visual and acoustic signals. Using field experiments that manipulated song and plumage colour, we tested if song, a possible long-range signal, is assessed before plumage colour in conspecific recognition. We find that divergent song and colour are assessed in sequence, and this pattern of sequential assessment is likely mediated by habitat structure and the extent of differences in signal characteristics. A broad survey of the literature suggests that many organisms from a wide range of taxa sequentially assess multimodal signals, with long-range signals attracting conspecifics for further assessment of close-range signals. Our results highlight the need to consider how signals are assessed when understanding multimodal signal evolution. Finally, given the results of our field experiments indicating sequential assessment of divergent song and colour in the recognition of conspecifics, we discuss the consequences of multimodal signal divergence for the origin of species, as changes in signals across different sensory modalities may influence the evolution of premating reproductive isolation.  相似文献   
210.
Weather, climate, and flood predictions are incorporated into human decisions in a wide variety of situations, including decisions related to hazardous hydrometeorological events. This article examines ethical aspects of such predictions and decisions, focusing on the case of the 1997 Red River flood in Grand Forks, North Dakota and East Grand Forks, Minnesota (US). The analysis employs a formal ethical framework and analytical method derived from medical and business ethics. The results of the analysis highlight issues related to forecast generation, communication of forecast meaning and uncertainty, responsibility for the use of forecasts in decision making, and trade-offs between the desire for forecast certainty and the risk of missed events. Implications of the analysis for the broader arenas of weather, climate, and flood prediction and disaster management are also discussed.  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