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   773篇
  免费   11篇
  国内免费   21篇
安全科学   66篇
废物处理   35篇
环保管理   176篇
综合类   131篇
基础理论   202篇
环境理论   3篇
污染及防治   109篇
评价与监测   52篇
社会与环境   22篇
灾害及防治   9篇
  2023年   6篇
  2022年   8篇
  2021年   9篇
  2020年   9篇
  2019年   18篇
  2018年   12篇
  2017年   30篇
  2016年   32篇
  2015年   23篇
  2014年   23篇
  2013年   49篇
  2012年   31篇
  2011年   47篇
  2010年   26篇
  2009年   39篇
  2008年   49篇
  2007年   41篇
  2006年   47篇
  2005年   33篇
  2004年   23篇
  2003年   33篇
  2002年   25篇
  2001年   12篇
  2000年   13篇
  1999年   10篇
  1998年   12篇
  1997年   14篇
  1996年   7篇
  1995年   11篇
  1994年   8篇
  1993年   14篇
  1992年   6篇
  1991年   10篇
  1990年   3篇
  1989年   8篇
  1988年   8篇
  1987年   8篇
  1986年   2篇
  1985年   9篇
  1984年   5篇
  1983年   2篇
  1982年   6篇
  1981年   6篇
  1980年   5篇
  1979年   6篇
  1978年   4篇
  1977年   1篇
  1975年   2篇
排序方式: 共有805条查询结果,搜索用时 218 毫秒
1.
2.
This paper demonstrates the potential for induced preference experiments to test previously unverified explanations of observed behavior in contingent valuation surveys. The NOAA Panel on Contingent Valuation called for experimental evidence on potential biases in the double referendum format. We test Carson, Groves, and Machina's (Incentives and informational properties of preference questions, Plenary address to the European Association of Resource and Environmental Economists, Oslo, Norway, June 1999) simple cost uncertainty and weighted averaging explanations of inconsistent responses to follow-up offers in such double referenda against a baseline of certainty and truthful preference revelation. The results find evidence to support the Weighted Average hypothesis. Results regarding the cost uncertainty hypothesis are more ambiguous and merit further investigation.  相似文献   
3.
The Countryside and Rights of Way Act 2000 places a duty on highways and national park authorities to establish local access forums (LAFs), to advise on the improvement of public access to land for the purposes of open air recreation and enjoyment. This paper examines these proposals in the context of recent academic and political debates about deliberative democracy, and empirical research on the nature and practice of existing access liaison groups and forums. While demonstrating that the proposed LAFs are consistent with contemporary constructs of participative, if not deliberative democracy, the paper argues that most existing groups and forums fall short of this ideal, in a number of significant respects. The paper proceeds to discuss the extent to which the draft regulations for LAFs in England and Wales address these issues, and concludes by questioning the extent to which such consultative arrangements can contribute to new forms of local governance.  相似文献   
4.
5.
6.
Analytical chemistry is an important tier of environmental protection and has been traditionally linked to compliance and/or exposure monitoring activities for environmental contaminants. The adoption of the risk management paradigm has led to special challenges for analytical chemistry applied to environmental risk analysis. Namely, methods developed for regulated contaminants may not be appropriate and/or applicable to risk management scenarios. This paper contains examples of analytical chemistry applied to risk management challenges broken down by the analytical approach and analyte for some selected work in our laboratory. Specific techniques discussed include stable association complex electrospray mass spectrometry (cESI-MS), gas chromatography-mass spectrometry (GC-MS), split-flow thin cell (SPLITT) fractionation and matrix-assisted laser desorption time of flight mass spectrometry (MALDI-ToF-MS). Specific analytes include haloacetic acids (HAA9), perchlorate, bromate, triazine degradation products, metal-contaminated colloids and Cryptosporidium parvum oocysts.  相似文献   
7.
Mercury is released to the environment from various anthropogenic and natural sources. This work is a compilation of mercury emissions from anthropogenic sources in Ontario, Canada. The goal of our study was to identify all sources of mercury, and develop an emission inventory of anthropogenic mercury in Ontario. The result of our investigation revealed that combustion of fossil fuels and emissions from landfill sites are two primary sources of mercury to the atmosphere. Other sources of significance are emissions from waste incinerators, various industrial activities, and cement production. Total mercury emission in Ontario is estimated as 4100 kg per year.  相似文献   
8.
Chorionic villus sampling (CVS) with either transcervical catheters or transabdominal needles is a widely-accepted method for prenatal diagnosis. However, there exists a small subset of patients in whom sampling is difficult or impossible with either route because of individual anatomic variations. A new method of chorionic villus biopsy has been developed to circumvent these problems, utilizing transvaginal chorionic needle aspiration guided by an intravaginal ultrasound probe. This technique was performed successfully in 15 patients in whom villi could not be obtained by either of the conventional methods. This method now makes CVS possible in essentially all women regardless of their uterine anatomy or placental placement; it may also prove useful for very early chorionic sampling.  相似文献   
9.
10.
Iniencephaly is an uncommon, but not rare, lesion involving a fusion between the posterior occipital bone and the cervical spine. Many cases are associated with other cranio-cervical abnormalities and anencephaly, and most are associated with other structural abnormalities. The prognosis is thought to be dismal. We describe a male infant, one of twins, who was diagnosed prenatally as having iniencephaly. The child was born without complication and has grown and thrived. This is the fourth patient with long-term survival with iniencephaly. We recommend that non-directive counselling be applied when presenting the findings of iniencephaly to parents.  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