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991.
Traffic speeds associated with implementation of 80 mph speed limits on West Texas rural interstates
Richard Retting Author Vitae Ivan Cheung Author Vitae 《Journal of Safety Research》2008,39(5):529-534
Problem
In 2006 Texas raised the daytime speed limit for passenger vehicles on segments of I-10 and I-20 from 75 to 80 mph. Methods: Traffic speeds were measured before and 3, 12, and 16 months after the limit was changed. Results: During the 16-month period following the speed limit increase, mean speeds of passenger vehicles on I-20 increased by 9 mph relative to the comparison road, where no speed limit change occurred and traffic speeds declined. On I-10 mean speeds increased by 4 mph relative to the comparison road. Limiting the analysis to the month before the speed limit change and 1 year later, the proportion of drivers exceeding 80 mph was 18 times higher on I-20 and 2 times higher on I-10. Discussion: The smaller speed increases on I-10 may be related to its proximity to the U.S. border with Mexico. Highly visible border patrol activity coincided with posting of the higher speed limit. Long-term monitoring in other states suggests that traffic speeds in Texas are likely to continue to increase. Impact on Industry: The present study adds to the wealth of evidence that increased speed limits lead to increased travel speeds. The primary countermeasures to reduce the risk of speed-related crashes include highly visible police traffic enforcement and the use of speed cameras accompanied by publicity. 相似文献992.
Meng PJ Lee HJ Wang JT Chen CC Lin HJ Tew KS Hsieh WJ 《Environmental pollution (Barking, Essex : 1987)》2008,156(1):67-75
Before 2001, the ecological protection area in the Kenting National Park (KTNP), southern Taiwan, was poorly described. In this study, a set of four-year data (2001-2004) of seawater qualities at 19 sampling sites around the Nanwan Bay in the KTNP was used to explore anthropogenic impacts to ecological environment, especially coral reefs. The parameters of water quality were analyzed immediately after collection. The results showed that higher values of nutrients and suspended solids were attributed to the higher run-off around Nanwan Bay. The fluxes of nutrients and suspended solids were consistently correlated to rainfall. Hence, equations were developed to calculate nutrient fluxes and suspended solids by using only rainfall data. Our results show that suspended solids and ammonia were the dominant factors leading to the drop in coral coverage. In summary, the water quality in the intertidal zone of Nanwan Bay has been degraded and required greater attention. 相似文献
993.
Comparison of regression coefficient and GIS-based methodologies for regional estimates of forest soil carbon stocks 总被引:4,自引:0,他引:4
Campbell JE Moen JC Ney RA Schnoor JL 《Environmental pollution (Barking, Essex : 1987)》2008,152(2):267-273
Estimates of forest soil organic carbon (SOC) have applications in carbon science, soil quality studies, carbon sequestration technologies, and carbon trading. Forest SOC has been modeled using a regression coefficient methodology that applies mean SOC densities (mass/area) to broad forest regions. A higher resolution model is based on an approach that employs a geographic information system (GIS) with soil databases and satellite-derived landcover images. Despite this advancement, the regression approach remains the basis of current state and federal level greenhouse gas inventories. Both approaches are analyzed in detail for Wisconsin forest soils from 1983 to 2001, applying rigorous error-fixing algorithms to soil databases. Resulting SOC stock estimates are 20% larger when determined using the GIS method rather than the regression approach. Average annual rates of increase in SOC stocks are 3.6 and 1.0 million metric tons of carbon per year for the GIS and regression approaches respectively. 相似文献
994.
Tkacz B Moody B Castillo JV Fenn ME 《Environmental pollution (Barking, Essex : 1987)》2008,155(3):409-425
Some of the greatest forest health impacts in North America are caused by invasive forest insects and pathogens (e.g., emerald ash borer and sudden oak death in the US), by severe outbreaks of native pests (e.g., mountain pine beetle in Canada), and fires exacerbated by changing climate. Ozone and N and S pollutants continue to impact the health of forests in several regions of North America. Long-term monitoring of forest health indicators has facilitated the assessment of forest health and sustainability in North America. By linking a nationwide network of forest health plots with the more extensive forest inventory, forest health experts in the US have evaluated current trends for major forest health indicators and developed assessments of future risks. Canada and Mexico currently lack nationwide networks of forest health plots. Development and expansion of these networks is critical to effective assessment of future forest health impacts. 相似文献
995.
996.
The input of acidity to Swedish forest soils through forestry between 1955 and 2010 is compared with the acid input from atmospheric deposition. Depending on region, input of acidity from forestry was the minor part (25–45%) of the study period’s accumulated acid input but is now the dominating source (140–270 molc ha−1 year−1). The net uptake of cations due to the increase in standing forest biomass, ranged between 35 and 45% of the forestry related input of acidity while whole-tree harvesting, introduced in the late 1990s, contributed only marginally (< 2%). The geographical gradient in acid input is reflected in the proportion of acidified soils in Sweden but edaphic properties contribute to variations in acidification sensitivity. It is important to consider the acid input due to increases in standing forest biomass in acidification assessments since it is long-term and quantitatively important.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01540-y. 相似文献
997.
998.
Environmental education and financial support of nature conservation are considered among the primary components of the environmentalist
dimension of ecotourism. The potential of environmental education calls for enhancing visitor environmental knowledge and
prompting change of visitor behavior. The present study addressed the evaluation of the environmentalist dimension of ecotourism
in the Dadia Forest Reserve. The first objective of the research was to study the influence of variables determined prior
to the visit, namely, visitor and visit characteristics, visitor environmental information sources, visitor pro-environmental
behavior, and visitation goals, on variables determined during the visit, that is, visitor participation in and satisfaction
from ecotourism activities. The second objective was to study the effect of selected variables on visitor knowledge and behavior
intentions. Visitor participation in and satisfaction from ecotourism activities were primarily controlled by visit characteristics.
Levels of visitor knowledge were quite satisfactory; however, coherence among knowledge items was rather loose. On the other
hand, behavior intention items revealed the highest possible degree of coherence, which should be attributed to the pervasive
influence of visitor satisfaction from watching birds at the Bird Observatory within the Dadia Forest Reserve. Ecotourism
activities, during which the main part of environmental knowledge was offered, exerted no effect on visitor knowledge; all
the same, they significantly influenced visitor behavior intentions. Overall, visitor behavior intentions revealed a considerable
potential of financing environmental protection and providing voluntary work in the frame of the environmental management
of the Dadia Forest Reserve. 相似文献
999.
1000.