全文获取类型
收费全文 | 4935篇 |
免费 | 106篇 |
国内免费 | 74篇 |
专业分类
安全科学 | 233篇 |
废物处理 | 244篇 |
环保管理 | 1296篇 |
综合类 | 422篇 |
基础理论 | 1152篇 |
环境理论 | 5篇 |
污染及防治 | 1181篇 |
评价与监测 | 345篇 |
社会与环境 | 187篇 |
灾害及防治 | 50篇 |
出版年
2023年 | 22篇 |
2022年 | 21篇 |
2021年 | 47篇 |
2020年 | 32篇 |
2019年 | 60篇 |
2018年 | 72篇 |
2017年 | 93篇 |
2016年 | 117篇 |
2015年 | 117篇 |
2014年 | 112篇 |
2013年 | 565篇 |
2012年 | 181篇 |
2011年 | 259篇 |
2010年 | 196篇 |
2009年 | 189篇 |
2008年 | 272篇 |
2007年 | 272篇 |
2006年 | 246篇 |
2005年 | 172篇 |
2004年 | 189篇 |
2003年 | 192篇 |
2002年 | 175篇 |
2001年 | 85篇 |
2000年 | 111篇 |
1999年 | 100篇 |
1998年 | 80篇 |
1997年 | 65篇 |
1996年 | 76篇 |
1995年 | 75篇 |
1994年 | 64篇 |
1993年 | 68篇 |
1992年 | 74篇 |
1991年 | 46篇 |
1990年 | 53篇 |
1989年 | 46篇 |
1988年 | 38篇 |
1987年 | 42篇 |
1986年 | 44篇 |
1985年 | 42篇 |
1984年 | 47篇 |
1983年 | 50篇 |
1982年 | 41篇 |
1981年 | 55篇 |
1980年 | 48篇 |
1979年 | 23篇 |
1978年 | 24篇 |
1977年 | 21篇 |
1976年 | 13篇 |
1975年 | 15篇 |
1971年 | 13篇 |
排序方式: 共有5115条查询结果,搜索用时 33 毫秒
131.
A stain-based screening method was developed to screen different catalyst coatings for their germicidal activity. A Baclight dead/live bacteria viability kit (invitrogen, molecular probes) was used for staining the cell. The screening was carried out following a standard procedure. This included loading cell suspension to solid surface and maintaining contact for 30 min, then staining with a mixture containing dyes. The stained cells were observed using an epifluorescent microscope and photographed with a CCD camera under UV. Metal-doped TiO2 coatings on AI plates were prepared and tested for non-UV germicidal activity without using UV. It was tested using model microorganisms such as Bakers Yeast (Saccharomyces cerevisiae), Bacillus subtilis, Pseudomonas putida, and Escherichia coli. On the basis of the germicidal activity of catalyst and the degree of damage caused to the cells, the stained cells may appear green (viable), green with red or yellow nuclei and yellow (compromised) or red (nonviable). According to their stained color, cells were counted to calculate the percentage of dead, live, and compromised cells. Compromised cells are cells that grow very slowly after reculturing indicating a degree of reversible cell damage. Screening the germicidal activity using this staining method is accurate and efficient, and requires less time than the culture-based method. A modification to the procedure for measuring germicidal activity of rough surfaces or fibrous coatings was developed. Both TiO2 and metal-doped TiO2 (Ag, Pt, Au, Cu) possess non-UV based germicidal activity. The germicidal activity of TiO2 was found to be related with its wetting property and can be improved by UV irradiation before testing. It is not greatly affected by contact time, indicating a fast acting germicidal activity. 相似文献
132.
Thallium: a review of public health and environmental concerns 总被引:22,自引:0,他引:22
Thallium (Tl) is a rare but widely dispersed element. All forms of thallium are soluble enough to be toxic to living organisms. Thallium is more toxic to humans than mercury, cadmium, lead, copper or zinc and has been responsible for many accidental, occupational, deliberate, and therapeutic poisonings since its discovery in 1861. Its chemical behavior resembles the heavy metals (lead, gold and silver) on the one hand and the alkali metals (K, Rb, Cs) on the other. It occurs almost exclusively in natural waters as monovalent thallous cation. The solubility of thallous compounds is relatively high so that monovalent thallium is readily transported through aqueous routes into the environment. Tl can be transferred from soils to crops readily and accrues in food crops. The fascinating chemistry and high toxicity potential make thallium and its compounds of particular scientific interest and environmental concern. Thallium was detected in base-metal mining effluents. The conventional removal of heavy metals from wastewater has little effect on thallium. In this review, various treatment options and removal technologies are enumerated in order to protect the environment from thallium toxicity. 相似文献
133.
Key performance indicators (KPIs) are critical measures for determining the health of a manufacturing plant in relationship to the plant’s goals. In today’s competitive environment, manufacturers cannot be careless about their business; in fact, they must ensure that their KPIs are effective and use them to make improvements when necessary. This paper describes a method for suggesting improvements to a manufacturer’s KPIs, based on the results achieved from a workshop to score the KPI on a number of predefined criteria. The approach uses a prospect theory approach to weight the scoring. Different problem formulations were derived that allow for both recommendations for improvements and the recommendations for disinvestments to over-performing KPIs. The authors applied the developed approach to two workshop outputs, each from independent manufacturers, and the results highlighted the significant difference between the two manufacturers in terms of improvement priorities and KPI assessment. The optimal improvement suggestions were compared to those found through a fast heuristic. It was determined that given the underlying assumptions of the approach that the heuristic solutions were just as adequate as the optimal ones. 相似文献
134.
135.
136.
John Rice 《Journal of Environmental Planning and Management》2016,59(1):44-61
Recent climate change projections and a push towards a universal agreement on carbon emission reductions suggest that firms will need to respond to future regulatory changes. This paper employs an influencing strategies lens to examine how large-scale firms might respond to future climate change regulations. The study uses a structured qualitative methodology to explore and explicate the strategic responses from 21 international firms to the proposed emissions trading scheme outlined in Australia's Garnaut Climate Change Review. The results of the analysis show that firms can use pre-emptive influencing strategies in attempts to shape and mould regulatory design parameters, secure high levels of transitional economic support, and shift the balance of public policies and expenditure. Complementary defensive strategies may also target policy makers and regulators with some of the potential negative consequences of the new regulations. 相似文献
137.
Recreational Diving Impacts on Coral Reefs and the Adoption of Environmentally Responsible Practices within the SCUBA Diving Industry 总被引:1,自引:0,他引:1
138.
Benchmarking Optical/Thermal Satellite Imagery for Estimating Evapotranspiration and Soil Moisture in Decision Support Tools
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jan M.H. Hendrickx Richard G. Allen Al Brower Aaron R. Byrd Sung‐ho Hong Fred L. Ogden Nawa Raj Pradhan Clarence W. Robison David Toll Ricardo Trezza Todd G. Umstot John L. Wilson 《Journal of the American Water Resources Association》2016,52(1):89-119
Generally, one expects evapotranspiration (ET) maps derived from optical/thermal Landsat and MODIS satellite imagery to improve decision support tools and lead to superior decisions regarding water resources management. However, there is lack of supportive evidence to accept or reject this expectation. We “benchmark” three existing hydrologic decision support tools with the following benchmarks: annual ET for the ET Toolbox developed by the United States Bureau of Reclamation, predicted rainfall‐runoff hydrographs for the Gridded Surface/Subsurface Hydrologic Analysis model developed by the U.S. Army Corps of Engineers, and the average annual groundwater recharge for the Distributed Parameter Watershed Model used by Daniel B. Stephens & Associates. The conclusion of this benchmark study is that the use of NASA/USGS optical/thermal satellite imagery can considerably improve hydrologic decision support tools compared to their traditional implementations. The benefits of improved decision making, resulting from more accurate results of hydrologic support systems using optical/thermal satellite imagery, should substantially exceed the costs for acquiring such imagery and implementing the remote sensing algorithms. In fact, the value of reduced error in estimating average annual groundwater recharge in the San Gabriel Mountains, California alone, in terms of value of water, may be as large as $1 billion, more than sufficient to pay for one new Landsat satellite. 相似文献
139.
140.
As the cost of car ownership has skyrocketed, urban biking has experienced the largest share increase of any transportation mode, rising by 40% between the years 2000 and 2014. Growing attention is being paid to the potential local economic development impacts of urban neighbourhoods becoming more bike-friendly. It is now a green economic development strategy in cities as diverse as Chicago, New York City, Portland, and San Francisco to increase bicycling as a transportation mode. This paper reports the results of a survey of 2032 responses from faculty, staff, and students of a car-dependent, downtown university. We use a mixed methods approach, including data from the American Community Survey, to support our arguments and to inform potential savings and economic benefit calculations that can be achieved from bicycle infrastructure investments and anticipated redistributed spending patterns. We argue that urban biking results in a green dividend that promotes local community development and more importantly results in zero carbon emissions. 相似文献