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   324篇
  免费   1篇
  国内免费   2篇
安全科学   4篇
废物处理   11篇
环保管理   22篇
综合类   101篇
基础理论   72篇
环境理论   1篇
污染及防治   84篇
评价与监测   13篇
社会与环境   15篇
灾害及防治   4篇
  2023年   2篇
  2022年   5篇
  2021年   5篇
  2019年   3篇
  2018年   4篇
  2017年   10篇
  2016年   11篇
  2015年   8篇
  2014年   8篇
  2013年   15篇
  2012年   15篇
  2011年   13篇
  2010年   8篇
  2009年   16篇
  2008年   19篇
  2007年   19篇
  2006年   10篇
  2005年   16篇
  2004年   15篇
  2003年   11篇
  2002年   12篇
  2001年   6篇
  2000年   5篇
  1999年   2篇
  1998年   4篇
  1997年   6篇
  1996年   2篇
  1995年   3篇
  1994年   6篇
  1992年   3篇
  1989年   3篇
  1977年   3篇
  1970年   2篇
  1964年   2篇
  1962年   2篇
  1958年   2篇
  1955年   2篇
  1952年   3篇
  1931年   3篇
  1930年   6篇
  1929年   2篇
  1925年   1篇
  1924年   1篇
  1923年   6篇
  1922年   3篇
  1921年   2篇
  1920年   1篇
  1919年   1篇
  1917年   1篇
  1913年   2篇
排序方式: 共有327条查询结果,搜索用时 31 毫秒
151.
The recognition of the hazards to young children of low-level lead intoxication and the widespread distribution of lead in the urban environment have resulted in massive federal, state, and local lead awareness and abatement programs. Two of the most significant exposure routes of lead to young children are the soils and dusts found within the child's home. Most state and federal lead abatement programs deal with lead-based paint contamination but often do not address the issue of soft-surface contamination, such as that of carpets, furniture, and draperies. Carpets can be a reservoir of contaminated soils and dusts; currently, there exists no standard method to test carpeted surfaces for lead contamination. This paper describes a study that uses X-ray fluorescence (XRF) to test carpeted surfaces for lead contamination. XRF technology is the standard technology used in lead-based paint testing and is known to be an accurate technique to test for lead in soils. This study uses a controlled laboratory atmosphere to evaluate this technology; the objectives are to determine: (1) a lower limit of detection for the instrument; and (2) whether soil loading levels can be differentiated by XRF using trace elements also present in the soil. Results indicate that XRF can easily differentiate soil loading levels (g soil/m2 carpet). The lower limit of detection of soil lead concentration on the carpet is a function of both soil lead concentration and soil loading; therefore, lead loading (mg Pb/m2) is a better indicator of detection limit than soil lead concentration. Lead loading detection levels from 108–258 mg Pb/m2 were obtained, as compared to a level of 10 000 mg/m2 (1 mg/cm2) for lead on painted surfaces as required by theLead-Based Paint Poisoning Prevention Act. XRF technology has the potential to be a fast, inexpensive screening technique for the evaluation of lead contamination on carpeted surfaces.  相似文献   
152.
153.
154.
In the first tier risk assessment (RA) of pesticides, risk for aquatic communities is estimated by using results from standard laboratory tests with algae, daphnids and fish for single pesticides such as herbicides, fungicides, and insecticides. However, fungi as key organisms for nutrient cycling in ecosystems as well as multiple pesticide applications are not considered in the RA. In this study, the effects of multiple low pesticide pulses using regulatory acceptable concentrations (RACs) on the dynamics of non-target aquatic fungi were investigated in a study using pond mesocosm. For that, fungi colonizing black alder (Alnus glutinosa) leaves were exposed to multiple, low pulses of 11 different pesticides over a period of 60 days using a real farmer''s pesticide application protocol for apple cropping. Four pond mesocosms served as treatments and 4 as controls. The composition of fungal communities colonizing the litter material was analyzed using a molecular fingerprinting approach based on the terminal Restriction Fragment Length Polymorphism (t-RFLP) of the fungal Internal Transcribed Spacer (ITS) region of the ribonucleic acid (RNA) gene(s). Our data indicated a clear fluctuation of fungal communities based on the degree of leaf litter degradation. However significant effects of the applied spraying sequence were not observed. Consequently also degradation rates of the litter material were not affected by the treatments. Our results indicate that the nutrient rich environment of the leaf litter material gave fungal communities the possibility to express genes that induce tolerance against the applied pesticides. Thus our data may not be transferred to other fresh water habitats with lower nutrient availability.  相似文献   
155.
Objective: In Sweden, a joint action method called SMADIT is in use, where the police quickly offer help from the social services or the dependency care and treatment service to suspected drink drivers. The objective of this article is to analyze the experiences of suspected drink drivers who accepted the offer of help and what it meant for them. The knowledge can be used to improve procedures and consultations. Furthermore, it can allow the basic premises of the method to be examined; for example, the importance of offering help quickly.

Methods: To enable comparisons over time, in-depth interviews were conducted with 12 suspected drink drivers on 2 occasions with 1 year between.

Results: To varying degrees the informants knew about their alcohol problems but were unsure whether they would have sought help by themselves. Therefore, the original ideas of the method with an initial contact with the social services or the dependency care and treatment service within 24 h was found to be important. However, the results also showed that some of the informants needed some time before the first meeting because they were in shock from the drink driving incident or in need of sleep. Therefore, the drink driver's situation and individual wishes always have to be considered. The article also shows that an encouraging attitude among the police, the social services, and the dependency care and treatment service is important for the success of the SMADIT method.

The informants are satisfied with the method and in retrospect the incident and the SMADIT offer of help are described as a turning point in their lives. One year after being offered help the informants were no longer focused solely on the personal consequences of drink driving, as they were shortly after the incident. Instead, they had gained insights into the harm they could have done to other road users when they drove while drunk.

Conclusions: One conclusion from this article is that SMADIT, as an innovative method that can be deployed more rapidly than other alcohol-impaired driving countermeasures, should be considered as a good complement to conventional methods to deal with drink driving. Based on the results, we recommend a trial of the joint action method against drink driving in other jurisdictions.  相似文献   

156.
Environmental Science and Pollution Research - Benzimidazoles are anthelmintics frequently used in sheep farming due to the high susceptibility of these animals to parasitic diseases. Sheep excreta...  相似文献   
157.
158.
159.
Mats Braun 《环境政策》2019,28(6):1105-1123
ABSTRACT

The East-West divide within the EU over climate policy has been frequently discussed. There is a tendency in the literature to focus on Poland and ignore the other countries in the central and eastern European region. Here it is argued that the institutionalised cooperation between the four countries in the Visegrad Group (the Czech Republic, Hungary, Poland and Slovakia) provides a crucial component for an understanding of how the participating countries approach EU climate negotiations. Here it is suggested that the group is important as a bargaining coalition but also as a reference point for the development of shared ‘Visegrad’ norms in the field. This is based on a case study of the Czech Republic’s approach to the 2014 negotiations on the 2030 climate and energy framework and the country’s cooperation with the other Visegrad countries on the issue.  相似文献   
160.
For a quantitative estimate of the ozone effect on vegetation reliable models for ozone uptake through the stomata are needed. Because of the analogy of ozone uptake and transpiration it is possible to utilize measurements of water loss such as sap flow for quantification of ozone uptake. This technique was applied in three beech (Fagus sylvatica) stands in Switzerland. A canopy conductance was calculated from sap flow velocity and normalized to values between 0 and 1. It represents mainly stomatal conductance as the boundary layer resistance in forests is usually small. Based on this relative conductance, stomatal functions to describe the dependence on light, temperature, vapour pressure deficit and soil moisture were derived using multivariate nonlinear regression. These functions were validated by comparison with conductance values directly estimated from sap flow. The results corroborate the current flux parameterization for beech used in the DO3SE model.  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