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   6篇
  国内免费   1篇
安全科学   14篇
废物处理   10篇
环保管理   27篇
综合类   63篇
基础理论   59篇
环境理论   2篇
污染及防治   119篇
评价与监测   15篇
社会与环境   21篇
灾害及防治   1篇
  2022年   4篇
  2021年   5篇
  2020年   5篇
  2019年   5篇
  2018年   9篇
  2017年   18篇
  2016年   6篇
  2015年   15篇
  2014年   9篇
  2013年   22篇
  2012年   11篇
  2011年   21篇
  2010年   13篇
  2009年   13篇
  2008年   14篇
  2007年   21篇
  2006年   10篇
  2005年   9篇
  2004年   18篇
  2003年   23篇
  2002年   9篇
  2001年   9篇
  2000年   2篇
  1999年   7篇
  1998年   3篇
  1997年   2篇
  1995年   3篇
  1994年   4篇
  1993年   2篇
  1992年   6篇
  1991年   3篇
  1989年   3篇
  1988年   1篇
  1983年   1篇
  1982年   1篇
  1981年   3篇
  1979年   2篇
  1978年   1篇
  1975年   1篇
  1974年   1篇
  1962年   3篇
  1960年   1篇
  1959年   1篇
  1956年   1篇
  1953年   1篇
  1949年   1篇
  1922年   2篇
  1920年   1篇
  1918年   1篇
  1913年   1篇
排序方式: 共有331条查询结果,搜索用时 46 毫秒
81.
Mitigation and Adaptation Strategies for Global Change - This paper was published on March 2017, Volume 22, Issue 3, 469–483pp, titled “Identification of structural breaks in the forest...  相似文献   
82.
83.
84.
Statistical prediction is a tool and aim in ecology and wildlife management and conservation. A prediction may either be supported by or contradicted by observations of an unknown set of observations. A contradiction occurs if the prediction is not included within the range of the unknown observations, i.e. the prediction misses the cloud of observations completely. Mixed-effects models, frequently used for statistical assessment of clustered data, carry information needed for calculating the probability of such contradictions. Here we present a new versatile statistic, the probability of contradiction (P (Contra)), that describes how often we would anticipate a new cluster of observations contradicting our predictions. Some benefits of P (Contra) are: (1) easy to calculate and intuitive interpretation, (2) comparability between datasets, (3) inclusion of residual correlation, (4) summary of the multitude of information from mixed models into one statistics, and (5) applicable to local mixed-effect models.  相似文献   
85.
Objective: Norway introduced a “Vision Zero” strategy in 2001, using multiple approaches, aiming toward a future in which no one will be killed or seriously injured in road traffic crashes (RTCs). Official statistics show that the number of fatally injured road users has declined substantially from 341 deaths in 2000 to 117 in 2015. In-depth crash investigations of all fatal RTCs started in Norway in 2005. The aim of this study was to investigate whether fatal crash characteristics, vehicle safety features, and prevalence of drugs and/or alcohol among fatally injured drivers and riders has changed during 2005–2015, accompanying the reduction in road fatalities.

Methods: Data on all car/van drivers and motorcycle/moped riders fatally injured in RTCs during 2005–2015 were extracted from Norwegian road traffic crash registries and combined with forensic toxicology data.

Results: The proportion of cars and motorcycles with antilock braking systems and cars with electronic stability control, increased significantly during the study period. The prevalence of nonuse of seat belts/helmets and speeding declined among both fatally injured drivers and riders. In addition, the prevalence of alcohol declined, though no significant change in the total prevalence of other substances was noted.

Conclusion: The observed changes toward more safety installations in cars and motorcycles and lower prevalence of driver-related risk factors like alcohol use, speeding, and nonuse of seat belts/helmets among fatally injured drivers/riders may have contributed to the decrease in road traffic deaths.  相似文献   

86.
Perfluoroalkyl substances (PFASs) in food and water from Faroe Islands   总被引:1,自引:1,他引:0  
Diet and drinking water are suggested to be major exposure pathways for perfluoroalkyl substances (PFASs). In this study, food items and water from Faroe Islands sampled in 2011/2012 were analyzed for 11 perfluoroalkyl carboxylic acids (PFCAs) and 4 perfluoroalkane sulfonic acids (PFSAs). The food samples included milk, yoghurt, crème fraiche, potatoes, fish, and fish feed, and the water samples included surface water and purified drinking water. In total, nine PFCAs and four PFSAs were detected. Generally, the levels of PFAS were in the lower picogram per gram range. Perfluorobutanoic acid was a major contributor to the total PFASs concentration in water samples and had a mean concentration of 750 pg/L. Perfluoroundecanoic acid (PFUnDA) was predominating in milk and wild fish with mean concentrations of 170 pg/g. Perfluorooctane sulfonic acid (PFOS) was most frequently detected in food items followed by PFUnDA, perfluorononanoic acid, and perfluorooctanoic acid (PFOA). Levels of PFUnDA and PFOA exceeded those of PFOS in milk and fish samples. Prevalence of long-chain PFCAs in Faroese food items and water is confirming earlier observations of their increase in Arctic biota. Predominance of short-chain and long-chain homologues indicates exposure from PFOS and PFOA replacement compounds.  相似文献   
87.
88.
Abstract: The occurrence of vascular plants was surveyed on 207 islands (size range 0.01–390.2 ha, number of plant species 1–449) offshore from the city of Helsinki in the Baltic Sea to examine the conservation value of these islands. We calculated a rarity score for each species (1/number of islands occupied by the species) and a biodiversity score for each island (sum of the rarity scores of each species present on the island). Positive correlations between species number and biodiversity score (r s = 0.97, p < 0.001) and between biodiversity score and island area (r s = 0.87, p < 0.001) indicated that these parameters are heavily dependent on island size. With the goal of including at least one occurrence (island) of all plant species, an iterative selection algorithm chose a set of 41 islands whose average size (29.3 ha) was four times the average size of all existing islands (7.0 ha). Strong nestedness ( N < 54) explains the concentration of plant species diversity on large islands. An operational strategy for selection of sites for protection is to complement the set produced by a selection algorithm with target species not yet included (e.g., endangered species with several occurrences). Comprehensive mapping and analysis of a taxonomic group will help integrate conservation biology into land-use planning and increase the quality of the networks of protected areas.  相似文献   
89.
90.
Thiobacilli may either attack coal-contained pyrite directly or contribute to its oxidation via catalysing the oxidation of ferrous salts by oxygen dissolved in water. The part played by either of the above mechanisms during pyrite removal from hard coals is discussed. This is followed by a review of experiments meant to identify the influence of coal rank, grain size, pyrite genesis and content, on pyrite removal efficiency over time. The paper reports on experiments to determine the seepage rate of the nutritive solution with bacteria, termed “biopulp”, in coal heaps. Investigations into the alteration of coal properties due to pyrite removal are dealt with. Concluding, plant dimensions and the costs of pyrite removal, as derived from two designs of relevant plants, are presented.  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