全文获取类型
收费全文 | 891篇 |
免费 | 37篇 |
国内免费 | 58篇 |
专业分类
安全科学 | 134篇 |
废物处理 | 4篇 |
环保管理 | 285篇 |
综合类 | 205篇 |
基础理论 | 116篇 |
污染及防治 | 67篇 |
评价与监测 | 110篇 |
社会与环境 | 47篇 |
灾害及防治 | 18篇 |
出版年
2024年 | 3篇 |
2023年 | 20篇 |
2022年 | 26篇 |
2021年 | 39篇 |
2020年 | 28篇 |
2019年 | 20篇 |
2018年 | 23篇 |
2017年 | 26篇 |
2016年 | 34篇 |
2015年 | 27篇 |
2014年 | 31篇 |
2013年 | 47篇 |
2012年 | 37篇 |
2011年 | 56篇 |
2010年 | 31篇 |
2009年 | 59篇 |
2008年 | 65篇 |
2007年 | 59篇 |
2006年 | 32篇 |
2005年 | 32篇 |
2004年 | 26篇 |
2003年 | 21篇 |
2002年 | 26篇 |
2001年 | 14篇 |
2000年 | 17篇 |
1999年 | 23篇 |
1998年 | 12篇 |
1997年 | 8篇 |
1996年 | 10篇 |
1995年 | 10篇 |
1994年 | 18篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1973年 | 1篇 |
排序方式: 共有986条查询结果,搜索用时 968 毫秒
581.
国道318线二郎山西口至康定县城沿线地质灾害发育特征及治理对策 总被引:4,自引:0,他引:4
在川藏公路关键段二郎山西口至康定县城长74km的范围内,共发育滑坡34处、崩塌33处、泥石流43处,其发育密度分别达0.46,0.44和0.58个(条)/km。分析表明,上述地质灾害的分布与该地所赋存的地形地貌、地持构造及岩性条件等密切相关。 相似文献
582.
Fish and seafood are important contributions to a healthy diet, but also contain persistent organic pollutants (POPs) like polybrominated diphenylethers (PBDEs) and polychlorinated biphenyls (PCBs). Discrepancies have been found between intake and accumulated levels of POPs, where fish consumers have had similar levels of POPs to the general population. Similarly fish oil consumption has been found to reduce accumulation of POPs. This study examined the accumulation of BDE47 or PCB153 in mice fed diets with different nutritional composition, using female mice with pre-weanling pups exposed through gestation and lactation. A fish-based diet was compared to a standard casein-based rodent diet. All diets had low background levels of environmental contaminants and were spiked with BDE47 or PCB153 to levels representing a realistic (∼0.004 μmol kgbw−1 d) or a high dietary exposure (∼1.3 μmol kgbw−1 d). Accumulation of BDE47 or PCB153 in offspring tissues after 18 d lactation reflected the maternal exposure levels. However, the pups of dams fed a fish-based diet had consistently lower BDE47 accumulation in liver, fat and stomach than pups from casein-fed dams. Similarly the pups of dams fed a high dose of PCB153 in a fish diet also accumulated less PCB153 than pups of the dams fed a casein diet, although not significant. In conclusion, the fish based diets seemed to reduce transfer of BDE47 and PCB153 from dams to pups. The study highlights that in-depth knowledge about nutritional impact on toxicokinetics is of great interest to vulnerable consumers. 相似文献
583.
Assessment of risk to humans of bisphenol A in marine and freshwater fish from Pearl River Delta, China 总被引:1,自引:0,他引:1
Bisphenol A (BPA) is a high production-volume chemical used in the manufacture of a wide variety of consumer products. However it is also a ubiquitous contaminant that can interfere with endocrine systems of wildlife and humans. China is the “world factory” and the Pearl River Delta is the major manufacturing center and is consequently polluted. Concentrations of BPA in meats of marketable fish had not been previously reported for this region. In the study upon which we report here concentrations of BPA were determined in 20 common species of freshwater and marine fish, collected from markets in Hong Kong, SAR, China. A comprehensive analytical method based on SPE extraction and liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was developed, validated and applied. The method limit of detection (LOD) and limit of quantification (LOQ) were 0.5 and 1.25 ng g−1 dw, respectively. BPA was detected in 19 species of fish at concentrations, ranging from 0.5 to 2.0 ng g−1 ww. Average daily BPA intake per person ranged from 1.1 × 102 ng d−1 for marine fish and 2.2 × 102 ng d−1 for freshwater fish. Concentrations of BPA in fish from Hong Kong markets unlikely would be causing adverse population-level effects in humans. 相似文献
584.
585.
This study evaluated the impact of small boat traffic on reaction distances of Marbled Murrelets (Brachyramphus marmoratus), in the marine waters of Pacific Rim National Park Reserve, British Columbia, Canada. Observers on moving boats recorded the minimum distance the boat came to murrelets on the water, and any disturbance reaction (fly, dive, no reaction). Out of the 7500 interactions 11.7% flew, 30.8% dove and 58.1% exhibited no flushing reaction. Using a product-limit analysis, we developed curves for the proportion of Marbled Murrelets flushing (dive or flight) as a function of reaction distance. Overall, the majority of Marbled Murrelets waited until boats were within 40 m before reacting, with 25% of the population reacting at 29.2m. A stepwise Cox regression indicated that age, boat speed, and boat density (loaded in that order), significantly affected flushing response. More juveniles flushed than adults (70.1 versus 51.7%), but at closer distances. Faster boats caused a greater proportion of birds to flush, and at further distances (25% of birds flushed at 40 m at speeds > 29 kph versus 28m at speeds <12kph). A stepwise logistic regression on diving and flight responses indicated that birds tended to fly completely out of feeding areas at the approach of boats travelling >28.8 kph and later in the season (July and August). Other secondary variables included; boat density and time of day. Discussion focused on possible management actions such as the application of speed limits, set back distances, and exclusion of boat traffic to protect Marbled Murrelets. 相似文献
586.
Hemlock Woolly Adelgid (Adelges tsugae) is spreading across forests in eastern North America, causing mortality of eastern hemlock (Tsuga canadensis [L.] Carr.) and Carolina hemlock (Tsuga caroliniana Engelm.). The loss of hemlock from riparian forests in Great Smoky Mountains National Park (GSMNP) may result in significant
physical, chemical, and biological alterations to stream environments. To assess the influence of riparian hemlock stands
on stream conditions and estimate possible impacts from hemlock loss in GSMNP, we paired hardwood- and hemlock-dominated streams
to examine differences in water temperature, nitrate concentrations, pH, discharge, and available photosynthetic light. We
used a Geographic Information System (GIS) to identify stream pairs that were similar in topography, geology, land use, and
disturbance history in order to isolate forest type as a variable. Differences between hemlock- and hardwood-dominated streams
could not be explained by dominant forest type alone as forest type yields no consistent signal on measured conditions of
headwater streams in GSMNP. The variability in the results indicate that other landscape variables, such as the influence
of understory Rhododendron species, may exert more control on stream conditions than canopy composition. The results of this study suggest that the
replacement of hemlock overstory with hardwood species will have minimal impact on long-term stream conditions, however disturbance
during the transition is likely to have significant impacts. Management of riparian forests undergoing hemlock decline should,
therefore, focus on facilitating a faster transition to hardwood-dominated stands to minimize long-term effects on water quality. 相似文献
587.
Management effectiveness evaluation has been recognized as an important mechanism for both reporting on and improving protected
area management. The Convention on Biological Diversity’s program of work on protected areas calls on all countries to implement
such systems. In 2004, the first whole of system assessment of park management effectiveness, based on the IUCN-WCPA Management
Effectiveness Evaluation Framework, was undertaken in New South Wales, Australia as part of a State of the Parks reporting
requirement. This article describes the development of the State of the Parks assessment tool, its elements, and how it addresses
the management effectiveness difficulties associated with assessments conducted across an extensive and diverse range of park
types. The importance of engaging staff, at all levels, throughout the process is highlighted, as well as the adjustments
made to the assessment tool based on staff feedback. While some results are presented, the main purpose of the article is
to identify and discuss important procedural and methodological considerations. These include balancing quantitative and qualitative
assessment approaches, achieving a comprehensive understanding of the management processes, and responding to any problems
associated with assessments. 相似文献
588.
589.
Xiaojiang Tang Yang Bai Anh Duong Martyn T. Smith Laiyu Li Luoping Zhang 《Environment international》2009,35(8):1210-1224
Formaldehyde, an economically important chemical, is classified as a human carcinogen that causes nasopharyngeal cancer and probably leukemia. As China is the largest producer and consumer of formaldehyde in the world, the Chinese population is potentially at increased risk for cancer and other associated health effects. In this paper we review formaldehyde production, consumption, exposure, and health effects in China. We collected and analyzed over 200 Chinese and English documents from scientific journals, selected newspapers, government publications, and websites pertaining to formaldehyde and its subsequent health effects.Over the last 20 years, China's formaldehyde industry has experienced unprecedented growth, and now produces and consumes one-third of the world's formaldehyde. More than 65% of the Chinese formaldehyde output is used to produce resins mainly found in wood products — the major source of indoor pollution in China. Although the Chinese government has issued a series of standards to regulate formaldehyde exposure, concentrations in homes, office buildings, workshops, public places, and food often exceed the national standards. In addition, there have been numerous reports of formaldehyde-induced health problems, including poisoning and cancer. The lack of quality epidemiological studies and basic data on exposed populations emphasizes the need for more extensive studies on formaldehyde and its related health effects in China. 相似文献
590.
Evaluating the air quality impacts of the 2008 Beijing Olympic Games: On-road emission factors and black carbon profiles 总被引:3,自引:0,他引:3
Xing Wang Dane Westerdahl Lung Chi Chen Ye Wu Jiming Hao Xiaochuan Pan Xinbiao Guo K. Max Zhang 《Atmospheric environment (Oxford, England : 1994)》2009,43(30):4535-4543
The aggressive traffic interventions and emission control measures implemented to improve air quality during the 2008 Beijing Olympic Games created a valuable case study to evaluate the effectiveness of these measures on mitigating air pollution and protecting public health. In this paper, we report the results from our field campaign in summer 2008 on the on-road emission factors of carbon monoxide, black carbon (BC) and ultrafine particles (UFP) as well as the ambient BC concentrations. The fleet average emission factors for light-duty gasoline vehicles (LDGV) showed considerable reduction in the Olympic year (2008) compared to the pre-Olympic year (2007). Our measurement of Black Carbon (BC), a primary pollutant, at different elevations at the ambient site suggests consistent decrease in BC concentrations as the height increased near the ground level, which indicates that the nearby ground level sources, probably dominated by traffic, contributed to a large portion of BC concentrations in the lower atmospheric layer in Beijing during summertime. These observations indicate that people living in near ground levels experience higher exposures than those living in higher floors in Beijing. The BC diurnal patterns on days when traffic control were in place during the Olympic Games were compared to those on non-traffic-control days in both 2007 and in 2008. These patterns strongly suggest that diesel trucks are a major source of summertime BC in Beijing. The median BC concentration on Olympic days was 3.7 μg m−3, which was dramatically lower than the value on non-traffic-control days, indicating the effectiveness of traffic control regulations in BC reduction in Beijing. 相似文献