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   917篇
  免费   8篇
  国内免费   15篇
安全科学   27篇
废物处理   53篇
环保管理   94篇
综合类   143篇
基础理论   204篇
环境理论   2篇
污染及防治   302篇
评价与监测   55篇
社会与环境   58篇
灾害及防治   2篇
  2023年   3篇
  2022年   15篇
  2021年   17篇
  2020年   8篇
  2019年   8篇
  2018年   29篇
  2017年   36篇
  2016年   36篇
  2015年   31篇
  2014年   30篇
  2013年   93篇
  2012年   47篇
  2011年   73篇
  2010年   56篇
  2009年   55篇
  2008年   66篇
  2007年   53篇
  2006年   47篇
  2005年   31篇
  2004年   29篇
  2003年   31篇
  2002年   19篇
  2001年   8篇
  2000年   6篇
  1999年   6篇
  1998年   8篇
  1997年   9篇
  1996年   4篇
  1995年   12篇
  1994年   2篇
  1993年   4篇
  1991年   4篇
  1990年   3篇
  1987年   2篇
  1981年   3篇
  1965年   7篇
  1964年   3篇
  1963年   4篇
  1962年   9篇
  1961年   11篇
  1960年   1篇
  1958年   2篇
  1957年   1篇
  1956年   1篇
  1954年   1篇
  1947年   1篇
  1942年   1篇
  1941年   2篇
  1938年   1篇
  1932年   1篇
排序方式: 共有940条查询结果,搜索用时 15 毫秒
621.
The present global environmental crisis is demanding serious rather than superficial changes within the cultural assumptions of human-to-human and human-to-nature relationships. In this sense, education is one of the strongest tools to model our future and a key factor of cultural change. One of the principal aims of Education for Sustainable Development (ESD) is to develop cognitive and affective skills that affect people's values, such as empathy and critical thinking. Together with compromise and responsibility towards a group, it is possible to build new values and ways to interact with both people and the environment. In the present study we used positive psychology principles in creating teaching interventions to empower empathy and critical thinking through an ESD programme at a Chilean primary school. The results show that an intervention of this kind helps to harmoniously build reflective thinking and empathy within students. This enables them to achieve important changes in their disposition to make sound personal and environmental decisions, and prepares them to positively meet imposing present and future challenges.  相似文献   
622.
Analyses of social structures in baleen whales are rare, and so far, they are thought to consist of mostly short and unstable associations. We investigated the association patterns of individual humpback whales from a summer feeding aggregation in the Gulf of St. Lawrence from 1997 to 2005. Photo-identified animals were sexed using genetic methods and were grouped into five categories: juvenile males/females, mature males and lactating/non-lactating females. We calculated half-weight association indices within and between the groups and found that 45% of the observation showed single animals and another 45% small groups (two to three) consisting mainly of mature animals besides lactating females. Using permutation tests, we found evidence for long-term associations between mature males and non-lactating females as well as among non-lactating females. Standardised lagged association rates revealed that these male–female groups disassociated quickly over about 2 weeks, whereas associations increased again towards the beginning of the breeding season. Non-lactating females of similar age engaged in multi-seasonal stable pairs for up to six consecutive feeding seasons; no mature male–female association was observed in consecutive years. The females with the most stable and long-term associations also had the highest reproductive output. While the risk of predation could not explain these long-term bonds, feeding cooperation seemed the most plausible explanation for group forming behaviour during the summer months.  相似文献   
623.
For a number of phthalates and especially for di(2-ethylhexyl)phthalate (DEHP), surprisingly high house dust concentrations are reported in the literature. Therefore, the uptake of the most prominent compounds DEHP and di-n-butylphthalate (DnBP) from plasticized indoor materials into house dust samples of different organic content has been experimentally determined. The experiments have been performed within 45 days which is sufficient for the more volatile phthalate (DnBP) to reach equilibrium conditions. DnBP reaches considerably higher concentrations in the chamber air compared to real room measurements and, thus, also elevated dust concentrations. In contrast, the mass transfer of DEHP in the dust via the gas phase was significantly lower. However, small chamber experiments showed elevated mass transfer of DEHP in case of direct contact between emission source and sink. This aspect is experimentally determined using an plasticized PVC polymer with and without direct contact to house dust. A transfer into the dust could be observed in dependence of the initial concentration in the material. However, the results do not allow the differentiation between the two uptake mechanisms via capillary forces and contact to the material’s boundary layer. The results illustrate that the reasons for elevated DEHP concentrations in dust indoors can be traced back to direct contact of source and sink, abrasion from the source, and transport via airborne particles.  相似文献   
624.
Anaerobic digestion of residual materials from animals and crops offers an opportunity to simultaneously produce bioenergy and plant fertilizers at single farms and in farm communities where input substrate materials and resulting digested residues are shared among member farms. A surplus benefit from this practice may be the suppressing of propagules from harmful biological pests like weeds and animal pathogens (e.g. parasites). In the present work, batch experiments were performed, where survival of seeds of seven species of weeds and non-embryonated eggs of the large roundworm of pigs, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37 °C) and thermophilic (55 °C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55 °C) was very clear as complete mortality, irrespective of weed species, was reached after less than 2 days. At mesophilic conditions, seeds of Avena fatua, Sinapsis arvensis, Solidago canadensis had completely lost germination ability, while Brassica napus, Fallopia convolvulus and Amzinckia micrantha still maintained low levels (~1%) of germination ability after 1 week. Chenopodium album was the only weed species which survived 1 week at substantial levels (7%) although after 11 d germination ability was totally lost. Similarly, at 55 °C, no Ascaris eggs survived more than 3 h of incubation. Incubation at 37 °C did not affect egg survival during the first 48 h and it took up to 10 days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites and weeds so that the digestates can be applied without risking spread of these pests.  相似文献   
625.
626.
Green waste is increasingly extracted from the material recycling chain and, as a result of the financial subsidy arising from the German renewable energy law for the generation of energy from renewable raw materials; it is fed into the energy recovery process in biomass power stations. A reduction in climate relevant gases is also linked to the material recovery of green waste – in particular when using composts gained from the process as a new raw material in different types of potting compost and plant culture media as a replacement for peat. Unlike energy recovery, material valorisation is not currently subsidised. Through the analysis of material and energy valorisation methods for green waste, with particular emphasis on primary resource consumption and CO2-balance, it could be determined that the use of green waste for energy generation and its recovery for material and peat replacement purposes can be considered to be on a par. Based on energy recovery or material oriented scenarios, it can be further deduced that no method on its own will achieve the desired outcome and that a combination of recycling processes is more likely to lead to a significant decrease of greenhouse gas emissions.  相似文献   
627.
We propose the wildlife premium mechanism as an innovation to conserve endangered large vertebrates. The performance‐based payment scheme would allow stakeholders in lower‐income countries to generate revenue by recovering and maintaining threatened fauna that can also serve as umbrella species (i.e., species whose protection benefits other species with which they co‐occur). There are 3 possible options for applying the premium: option 1, embed premiums in a carbon payment; option 2, link premiums to a related carbon payment, but as independent and legally separate transactions; option 3, link premiums to noncarbon payments for conserving ecosystem services (PES). Each option presents advantages, such as incentive payments to improve livelihoods of rural poor who reside in or near areas harboring umbrella species, and challenges, such as the establishment of a subnational carbon credit scheme. In Kenya, Peru, and Nepal pilot premium projects are now underway or being finalized that largely follow option 1. The Kasigau (Kenya) project is the first voluntary carbon credit project to win approval from the 2 leading groups sanctioning such protocols and has already sold carbon credits totaling over $1.2 million since June 2011. A portion of the earnings is divided among community landowners and projects that support community members and has added over 350 jobs to the local economy. All 3 projects involve extensive community management because they occur on lands where locals hold the title or have a long‐term lease from the government. The monitoring, reporting, and verification required to make premium payments credible to investors include transparent methods for collecting data on key indices by trained community members and verification of their reporting by a biologist. A wildlife premium readiness fund would enable expansion of pilot programs needed to test options beyond those presented here. Mejora de la Conservación, Servicios del Ecosistema y Calidad de Vida Local Mediante un Mecanismo de Compensación de Vida Silvestre  相似文献   
628.
This paper examines a first version of a Comprehensive Action Determination Model (CADM) of ecological behaviour that incorporates intentional, normative, situational, and habitual influences on environmentally friendly behaviour. The main assumptions of the theory of planned behaviour (TPB), the norm-activation model (NAM), the theoretical concept of habit and the ipsative theory of behaviour were integrated into a comprehensive model. The model was tested using a structural equation modelling approach on a sample of 389 students in the domain of travel mode choice and compared to established less comprehensive models (TPB, NAM and a combination of both). The results show that all compared models had a good to excellent model fit and explained a substantial amount of variation in travel mode choice. The CADM, however, explained the greatest degree of variation as compared with the other models, at 65%. Subjective and objective situational constraints were responsible for most of the variation in travel mode choice in the CADM, but intentions and habits also had a significant impact. The influence of social and personal norms was mediated by habits and intention, while habits moderated the relationship between intention and behaviour. The importance of the CADM as a framework for other domains of ecological behaviour is also discussed.  相似文献   
629.
This paper attempts to replicate a safety climate model originally tested in Australia to assess its applicability in a different context: namely, across production workers in 22 medium-sized metal processing organizations in Austria. The model postulates that safety knowledge and safety motivation mediate the relation between safety climate on the one hand and safety compliance and participation on the other. Self-report data from 1075 employees were analyzed using structural equation modeling (SEM). The results of the replication study largely confirmed the original safety climate model. However, in addition to indirect effects, direct links between safety climate and actual safety behavior were found.  相似文献   
630.
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