全文获取类型
收费全文 | 971篇 |
免费 | 18篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 34篇 |
废物处理 | 32篇 |
环保管理 | 173篇 |
综合类 | 113篇 |
基础理论 | 284篇 |
环境理论 | 1篇 |
污染及防治 | 243篇 |
评价与监测 | 68篇 |
社会与环境 | 42篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 27篇 |
2022年 | 32篇 |
2021年 | 13篇 |
2020年 | 12篇 |
2019年 | 28篇 |
2018年 | 22篇 |
2017年 | 32篇 |
2016年 | 39篇 |
2015年 | 24篇 |
2014年 | 42篇 |
2013年 | 77篇 |
2012年 | 35篇 |
2011年 | 82篇 |
2010年 | 52篇 |
2009年 | 42篇 |
2008年 | 46篇 |
2007年 | 55篇 |
2006年 | 59篇 |
2005年 | 32篇 |
2004年 | 32篇 |
2003年 | 36篇 |
2002年 | 33篇 |
2001年 | 19篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 15篇 |
1995年 | 5篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1965年 | 1篇 |
1941年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有996条查询结果,搜索用时 15 毫秒
191.
Objectives
Motorcycle registrations have risen in recent years. Although motorcyclist crash fatalities in 2009 were 16% lower than in 2008, they were double the number of deaths in 1997. The present study examined current motorcyclists’ travel patterns and views of motorcycle helmets and other safety topics.Methods
Motorcycle drivers were interviewed in a national telephone survey conducted in 2009. A weighted sample of 1,606 motorcyclists resulted from adjusting for the oversampling of those younger than 40 and those in the three states without a motorcycle helmet use law (Illinois, Iowa, New Hampshire). All analyses were based on the weighted sample, which was intended to result in a nationally representative sample of motorcyclists.Results
About one-quarter of respondents said they did not always wear helmets. Of these respondents, 57% said a law requiring helmet use would persuade them to do so, and 27% said nothing would. Ninety-four percent of respondents in states with universal helmet laws said they always ride helmeted, compared with about half of respondents in other states. About half of all respondents favored these laws. About three-quarters said they believe helmets keep riders safer, including two-thirds of respondents who oppose universal laws and almost half of drivers who rarely/never wear helmets. Drivers ages 18–29 and drivers of sport/unclad sport, sport touring, and super sport motorcycles were more likely to always wear helmets, support universal helmet laws, and believe helmets keep riders safer. About half of respondents said antilock braking systems (ABS) enhance safety and that they would get ABS on their next motorcycle. Less than one-quarter thought an airbag would protect a motorcyclist in a crash, and even fewer would consider getting one on their next motorcycle. Forty-three percent of motorcyclists said they had crashed at least once; 62% of the most recent crashes involved no vehicles besides the motorcycle. Respondents reported riding their motorcycles about 5,400 miles, on average, during the past year. Drivers ages 18–29 reported riding fewer miles, on average, than older drivers and more often rode at night and to/from work or school. Drivers of touring and sport touring motorcycles traveled more miles and took more long trips.Conclusions
Motorcyclists’ travel patterns and views vary widely, but there are distinct patterns by driver age and motorcycle type. Drivers who believe helmets keep riders safer are more likely to always wear them, but this belief appears insufficient to motivate some drivers to wear them. However, universal helmet laws appear effective in increasing helmet use. Many drivers are receptive to purchasing ABS on their next motorcycle.Impact on industry
States should be encouraged to enact universal helmet laws, and motorcycle manufacturers should be encouraged to offer ABS. 相似文献192.
193.
An electromigration transport model for non-reactive ion transport in unsaturated soil was developed and tested against laboratory experiments. This model assumed the electric potential field was constant with respect to time, an assumption valid for highly buffered soil, or when the electrode electrolysis reactions are neutralized. The model also assumed constant moisture contents and temperature with respect to time, and that electroosmotic and hydraulic transport of water through the soil was negligible. A functional relationship between ionic mobility and the electrolyte concentration was estimated using the chemical activity coefficient. Tortuosity was calculated from a mathematical relationship fitted to the electrical conductivity of the bulk pore water and soil moisture data. The functional relationship between ionic mobility, pore-water concentration, and tortuosity as a function of moisture content allowed the model to predict ion transport in heterogeneous unsaturated soils. The model was tested against laboratory measurements assessing anionic electromigration as a function of moisture content. In the test cell, a strip of soil was spiked with red dye No 40 and monitored for a 24-h period while a 10-mA current was maintained between the electrodes. Electromigration velocities predicted by the electromigration transport model were in agreement with laboratory experimental results. Both laboratory-measured and model-predicted dye migration results indicated a maximum transport velocity at moisture contents less than saturation due to competing effects between current density and tortuosity as moisture content decreases. 相似文献
194.
Roviello Valentina Gilhen-Baker Melinda Roviello Giovanni N. Lichtfouse Eric 《Environmental Chemistry Letters》2022,20(5):2729-2734
Environmental Chemistry Letters - 相似文献
195.
Morin-Crini Nadia Lichtfouse Eric Liu Guorui Balaram Vysetti Ribeiro Ana Rita Lado Lu Zhijiang Stock Friederike Carmona Eric Teixeira Margarida Ribau Picos-Corrales Lorenzo A. Moreno-Piraján Juan Carlos Giraldo Liliana Li Cui Pandey Abhishek Hocquet Didier Torri Giangiacomo Crini Grégorio 《Environmental Chemistry Letters》2022,20(4):2311-2338
Environmental Chemistry Letters - Water contamination by emerging contaminants is increasing in the context of rising urbanization, industrialization, and agriculture production. Emerging... 相似文献
196.
Dutta Deblina Arya Shashi Kumar Sunil Lichtfouse Eric 《Environmental Chemistry Letters》2022,20(2):971-974
Environmental Chemistry Letters - 相似文献
197.
C. Susmita Kumar S. P. Jeevan Chintagunta Anjani Devi Lichtfouse Eric Naik Bhojaraj P. Ramya Kumari Kalyani Kumar Sanjay 《Environmental Chemistry Letters》2022,20(3):2135-2164
Environmental Chemistry Letters - Climate change is predicted to cause severe loss in agricultural production by increasing disease epidemics and intensifying abiotic stresses. Therefore,... 相似文献
198.
Jabiol Jérémy Chauvet Eric Guérold François Bouquerel Jonathan Usseglio-Polatera Philippe Artigas Joan Margoum Christelle Le Dréau Matthieu Moreira Aurélie Mazzella Nicolas Gouy Véronique 《Environmental science and pollution research international》2022,29(20):29296-29313
Environmental Science and Pollution Research - Freshwater contamination by pesticides in agricultural landscapes is of increasing concern worldwide, with strong pesticide impacts on biodiversity,... 相似文献
199.
Climatic warming is associated with organisms breeding earlier in the season than is typical for their species. In some species, however, response to warming is more complex than a simple advance in the timing of all life history events preceding reproduction. Disparities in the extent to which different components of the reproductive phenology of organisms vary with climatic warming indicate that not all life history events are equally responsive to environmental variation. Here, we propose that our understanding of phenological response to climate change can be improved by considering entire sequences of events comprising the aggregate life histories of organisms preceding reproduction. We present results of a two-year warming experiment conducted on 33 individuals of three plant species inhabiting a low-arctic site. Analysis of phenological sequences of three key events for each species revealed how the aggregate life histories preceding reproduction responded to warming, and which individual events exerted the greatest influence on aggregate life history variation. For alpine chickweed (Cerastium alpinum), warming elicited a shortening of the duration of the emergence stage by 2.5 days on average, but the aggregate life history did not differ between warmed and ambient plots. For gray willow (Salix glauca), however, all phenological events monitored occurred earlier on warmed than on ambient plots, and warming reduced the aggregate life history of this species by 22 days on average. Similarly, in dwarf birch (Betula nana), warming advanced flower bud set, blooming, and fruit set and reduced the aggregate life history by 27 days on average. Our approach provides important insight into life history responses of many organisms to climate change and other forms of environmental variation. Such insight may be compromised by considering changes in individual phenological events in isolation. 相似文献
200.
Phenology: response, driver, and integrator. 总被引:1,自引:0,他引:1