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   364篇
  免费   4篇
  国内免费   4篇
安全科学   19篇
废物处理   9篇
环保管理   57篇
综合类   87篇
基础理论   54篇
污染及防治   109篇
评价与监测   21篇
社会与环境   11篇
灾害及防治   5篇
  2023年   3篇
  2022年   5篇
  2021年   19篇
  2020年   4篇
  2019年   6篇
  2018年   9篇
  2017年   13篇
  2016年   10篇
  2015年   15篇
  2014年   17篇
  2013年   25篇
  2012年   17篇
  2011年   29篇
  2010年   17篇
  2009年   19篇
  2008年   23篇
  2007年   18篇
  2006年   22篇
  2005年   17篇
  2004年   11篇
  2003年   13篇
  2002年   10篇
  2001年   4篇
  2000年   5篇
  1999年   3篇
  1998年   4篇
  1997年   3篇
  1996年   2篇
  1995年   4篇
  1994年   1篇
  1993年   3篇
  1992年   2篇
  1991年   3篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1984年   1篇
  1982年   1篇
  1981年   2篇
  1979年   1篇
  1978年   1篇
  1974年   1篇
  1971年   1篇
  1970年   1篇
  1966年   1篇
  1965年   1篇
  1964年   1篇
排序方式: 共有372条查询结果,搜索用时 31 毫秒
111.
This paper highlights some of the issues facing owner/operators when attempting to align personnel, procedures, and equipment to achieve cost effective and safe operating performance. Each issue is presented using simple and practical thoughts toward life, collected from fortune cookies consumed during the technical editing of CCPS's Guidelines for Safe and Reliable Instrumented Protective Systems (2007).  相似文献   
112.
The personal assessments of the current and expected future state of the environment by 3232 community respondents in 18 nations were investigated at the local, national, and global spatial levels. These assessments were compared to a ranking of each country's environmental quality by an expert panel. Temporal pessimism (“things will get worse”) was found in the assessments at all three spatial levels. Spatial optimism bias (“things are better here than there”) was found in the assessments of current environmental conditions in 15 of 18 countries, but not in the assessments of the future. All countries except one exhibited temporal pessimism, but significant differences between them were common. Evaluations of current environmental conditions also differed by country. Citizens' assessments of current conditions, and the degree of comparative optimism, were strongly correlated with the expert panel's assessments of national environmental quality. Aside from the value of understanding global trends in environmental assessments, the results have important implications for environmental policy and risk management strategies.  相似文献   
113.
The Aguadulce aquifer unit in southeastern Spain is a complex hydrogeological system because of the varied lithology of the aquifer strata and the variability of the processes that can take place within the unit. Factorial analysis of the data allowed the number of variables to be reduced to 3 factors, which were found to be related to such physico-chemical processes as marine intrusion and leaching of saline deposits. Variographic analysis was applied to these factors, culminating in a study of spatial distribution using ordinary kriging. Mapping of the factors allowed rapid differentiation of some of the processes that affect the waters of the Gador carbonate aquifer within the Aguadulce unit, without the need to recur to purely hydrogeochemical techniques. The results indicate the existence of several factors related to salinity: marine intrusion, paleowaters, and/or leaching of marls and evaporitic deposits. The techniques employed are effective, and the results conform to those obtained using hydrogeochemical methods (vertical records of conductivity and temperature, ion ratios, and others). The findings of this study confirm that the application of such analytical methods can provide a useful assessment of factors affecting groundwater composition.  相似文献   
114.
As the production of nanoparticles of ZnO, TiO2 and CuO is increasing, their (eco)toxicity to bacteria Vibrio fischeri and crustaceans Daphnia magna and Thamnocephalus platyurus was studied with a special emphasis on product formulations (nano or bulk oxides) and solubilization of particles. Our innovative approach based on the combination of traditional ecotoxicology methods and metal-specific recombinant biosensors allowed to clearly differentiate the toxic effects of metal oxides per se and solubilized metal ions. Suspensions of nano and bulk TiO2 were not toxic even at 20 g l(-1). All Zn formulations were very toxic: L(E)C50 (mg l(-1)) for bulk ZnO, nanoZnO and ZnSO4.7H2O: 1.8, 1.9, 1.1 (V. fischeri); 8.8, 3.2, 6.1 (D. magna) and 0.24, 0.18, 0.98 (T. platyurus), respectively. The toxicity was due to solubilized Zn ions as proved with recombinant Zn-sensor bacteria. Differently from Zn compounds, Cu compounds had different toxicities: L(E)C50 (mg l(-1)) for bulk CuO, nano CuO and CuSO4: 3811, 79, 1.6 (V. fischeri), 165, 3.2, 0,17 (D. magna) and 95, 2.1, 0.11 (T. platyurus), respectively. Cu-sensor bacteria showed that toxicity to V. fischeri and T. platyurus was largely explained by soluble Cu ions. However, for Daphnia magna, nano and bulk CuO proved less bioavailable than for bacterial Cu-sensor. This is the first evaluation of ZnO, CuO and TiO2 toxicity to V. fischeri and T. platyurus. For nano ZnO and nano CuO this is also a first study for D. magna.  相似文献   
115.
Lin AY  Yu TH  Lin CF 《Chemosphere》2008,74(1):131-141
This is a comprehensive study of the occurrence of antibiotics, hormones and other pharmaceuticals in water sites that have major potential for downstream environmental contamination. These include residential (hospitals, sewage treatment plants, and regional discharges), industrial (pharmaceutical production facilities), and agricultural (animal husbandries and aquacultures) waste streams. We assayed 23 Taiwanese water sites for 97 targeted compounds, of which a significant number were detected and quantified. The most frequently detected compounds were sulfamethoxazole, caffeine, acetaminophen, and ibuprofen, followed closely by cephalexin, ofloxacin, and diclofenac, which were detected in >91% of samples and found to have median (maximum) concentrations of 0.2 (5.8), 0.39 (24.0), 0.02 (100.4), 0.41 (14.5), 0.15 (31.4), 0.14 (13.6) and 0.083 (29.8) microg/L, respectively. Lincomycin and acetaminophen had high measured concentrations (>100 microg/L), and 35 other pharmaceuticals occurred at the microg/L level. These incidence and concentration results correlate well with published data for other worldwide locations, as well as with Taiwanese medication usage data, suggesting a human contamination source. Many pharmaceuticals also occurred at levels exceeding predicted no-effect concentrations (PNEC), warranting further investigation of their occurrence and fate in receiving waters, as well as the overall risks they pose for local ecosystems and human residents. The information provided here will also be useful for development of strategies for regulation and remediation.  相似文献   
116.
The vast majority of dry cleaners worldwide use the toxic chemical perchloroethylene (PCE), which is associated with a number of adverse health and environmental impacts. Professional wet cleaning was developed as a nontoxic alternative to PCE dry cleaning but has not been widely adopted as substitute technology. In the greater Los Angeles, CA, region, a demonstration project was set up to showcase this technology and evaluate its commercial viability by converting seven cleaners from PCE dry cleaning to professional wet cleaning. The demonstration site cleaners who switched to professional wet cleaning were able to maintain their level of service and customer base while lowering operating costs. The cleaners were able to transition to professional wet cleaning without a great degree of difficulty and expressed a high level of satisfaction with professional wet cleaning. Crucial to this success was the existence of the demonstration project, which helped to develop a supporting infrastructure for professional wet cleaning that had otherwise been lacking in the garment care industry.  相似文献   
117.
Actor-level data on large-scale commercial agriculture in Sub-Saharan Africa are scarce. The peculiar choice of transnational investing in African land has, therefore, been subject to conjecture. Addressing this gap, we reconstructed the underlying logics of investment location choices in a Bayesian network, using firm- and actor-level interview and spatial data from 37 transnational agriculture and forestry investments across 121 sites in Mozambique, Zambia, Tanzania, and Ethiopia. We distinguish four investment locations across gradients of resource frontiers and agglomeration economies to derive the preferred locations of different investors with varied skillsets and market reach (i.e., track record). In contrast to newcomers, investors with extensive track records are more likely to expand the land use frontier, but they are also likely to survive the high transaction costs of the pre-commercial frontier. We highlight key comparative advantages of Southern and Eastern African frontiers and map the most probable categories of investment locations.Supplementary informationThe online version contains supplementary material available at 10.1007/s13280-021-01682-z.  相似文献   
118.
119.
Although no precise figures are available, many congenital brain lesions arise from intrauterine disruption, frequently due to obstetric complications. The most common entities include intracranial hemorrhage, ischemic lesions, thrombosis of venous vessels and infections. Accurate prenatal diagnosis is possible in many of these cases. However, the findings may be subtle, particularly in the early stage of the disruptive process. Identification of these conditions requires therefore specific expertise, the combination of fetal neurosonography and magnetic resonance, and frequently there is a need for serial examinations. Targeted diagnostic imaging should be offered to obstetric patients with conditions predisposing to prenatal cerebral insults. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
120.
Discussions of municipal solid waste (MSW) management are influenced increasingly by the concept of the waste hierarchy which, broadly speaking, places landfill as the least acceptable option for dealing with MSW, followed by incineration, recycling, re-use and reduction at source. In this paper, we want to question the wisdom of applying the waste hierarchy in a region with a low population density. The hierarchy was first developed with reference to the high population density areas such as the core of the EU. However, in low population density areas the economics of the various approaches to MSW is likely to be quite different. As a result, the application of the hierarchy could place an undue economic burden on a region relative to the environmental benefits that might arise. We estimate the costs, both internal and external, of the various methods of dealing with MSW in an area with the appropriate population density, drawing on information from a wide variety of sources. We find that landfill is significantly cheaper than in high population density areas, even when account is taken of the associated externalities. In addition, it is generally cheaper than the alternative methods. As such, we conclude that landfill should not be shunned as a disposal method in low population density areas.  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