全文获取类型
收费全文 | 994篇 |
免费 | 26篇 |
国内免费 | 19篇 |
专业分类
安全科学 | 38篇 |
废物处理 | 34篇 |
环保管理 | 170篇 |
综合类 | 147篇 |
基础理论 | 245篇 |
环境理论 | 4篇 |
污染及防治 | 265篇 |
评价与监测 | 94篇 |
社会与环境 | 34篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 8篇 |
2022年 | 6篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 22篇 |
2017年 | 18篇 |
2016年 | 31篇 |
2015年 | 23篇 |
2014年 | 18篇 |
2013年 | 87篇 |
2012年 | 49篇 |
2011年 | 63篇 |
2010年 | 42篇 |
2009年 | 53篇 |
2008年 | 59篇 |
2007年 | 79篇 |
2006年 | 65篇 |
2005年 | 48篇 |
2004年 | 53篇 |
2003年 | 42篇 |
2002年 | 35篇 |
2001年 | 29篇 |
2000年 | 17篇 |
1999年 | 13篇 |
1998年 | 17篇 |
1997年 | 8篇 |
1996年 | 18篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 2篇 |
1990年 | 8篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1954年 | 3篇 |
1948年 | 2篇 |
1941年 | 1篇 |
1939年 | 2篇 |
1919年 | 1篇 |
1914年 | 1篇 |
排序方式: 共有1039条查询结果,搜索用时 62 毫秒
1.
2.
3.
4.
The feasibility of using U.K. coal-fired power station waste materials for artificial reef production is being examined. in June, 1989, an experimental artificial reef was constructed in Poole Bay, off the central south coast of the U.K., using three different mixtures of pulverised fuel ash (PFA), flue gas desulphurisation (FGD) gypsum and slurry, stabilized with cement and formed into blocks. Fifty tonnes of 40 × 20 × 20 cm blocks were formed into eight conical reef units replicating three different PFA/gypsum mixtures and one concrete control. the reef structure is 10m below chart datum on a flat sandy sea-bed.
Combustion of coal concentrates the heavy metal content in the resultant ash. the purpose of stabilization of the ash as blocks is twofold: to immobilize heavy metals (or other components) and to provide hard substratum for the attachment of organisms. to examine the effectiveness of this stabilization and hence the environmental compatibility of the block materials, heavy metal (Cd, Cr, Cu, Pb, Mn, Ni, Zn) content of the blocks has been monitored routinely over two years, to determine leaching rates. Sectional profiles indicate partial replacement of calcium content by magnesium. Associated with this there has also been some redistribution of heavy metals. Only in the case of cadmium has there been a detectable loss from the surface of blocks. Chromium and manganese concentrations appear to have increased. the metal content of the reef epibiota (including ascidians, Ascidia mentula; hydroids, Halecium spp.; bryozoans, Bugula spp. and red algae) growing on the ash blocks has been compared to that of epibiota attached to the concrete controls and surrounding sea-bed. to date no evidence of excess bioaccumulation of metals has been detected.
The physical integrity of the ash reef blocks has been maintained. There is evidence that the blocks are increasing in compressive strength.
An indication of the fishery enhancement potential of the experimental structure is given by the presence of eight commercially fished species (crustaceans and molluscs) including lobsters (Homarus gammarus). 相似文献
Combustion of coal concentrates the heavy metal content in the resultant ash. the purpose of stabilization of the ash as blocks is twofold: to immobilize heavy metals (or other components) and to provide hard substratum for the attachment of organisms. to examine the effectiveness of this stabilization and hence the environmental compatibility of the block materials, heavy metal (Cd, Cr, Cu, Pb, Mn, Ni, Zn) content of the blocks has been monitored routinely over two years, to determine leaching rates. Sectional profiles indicate partial replacement of calcium content by magnesium. Associated with this there has also been some redistribution of heavy metals. Only in the case of cadmium has there been a detectable loss from the surface of blocks. Chromium and manganese concentrations appear to have increased. the metal content of the reef epibiota (including ascidians, Ascidia mentula; hydroids, Halecium spp.; bryozoans, Bugula spp. and red algae) growing on the ash blocks has been compared to that of epibiota attached to the concrete controls and surrounding sea-bed. to date no evidence of excess bioaccumulation of metals has been detected.
The physical integrity of the ash reef blocks has been maintained. There is evidence that the blocks are increasing in compressive strength.
An indication of the fishery enhancement potential of the experimental structure is given by the presence of eight commercially fished species (crustaceans and molluscs) including lobsters (Homarus gammarus). 相似文献
5.
Smith PN Cobb GP Godard-Codding C Hoff D McMurry ST Rainwater TR Reynolds KD 《Environmental pollution (Barking, Essex : 1987)》2007,150(1):41-64
Here we review mechanisms and factors influencing contaminant exposure among terrestrial vertebrate wildlife. There exists a complex mixture of biotic and abiotic factors that dictate potential for contaminant exposure among terrestrial and semi-terrestrial vertebrates. Chemical fate and transport in the environment determine contaminant bioaccessibility. Species-specific natural history characteristics and behavioral traits then play significant roles in the likelihood that exposure pathways, from source to receptor, are complete. Detailed knowledge of natural history traits of receptors considered in conjunction with the knowledge of contaminant behavior and distribution on a site are critical when assessing and quantifying exposure. We review limitations in our understanding of elements of exposure and the unique aspects of exposure associated with terrestrial and semi-terrestrial taxa. We provide insight on taxa-specific traits that contribute, or limit exposure to, transport phenomenon that influence exposure throughout terrestrial systems, novel contaminants, bioavailability, exposure data analysis, and uncertainty associated with exposure in wildlife risk assessments. Lastly, we identify areas related to exposure among terrestrial and semi-terrestrial organisms that warrant additional research. 相似文献
6.
7.
8.
Frede Ø. Andersen Michael Jørgensen Henning S. Jensen 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):465-474
One of the methods to diminish the internal phosphorus (P) loading is inactivation of P by aluminum (Al). After addition of
Al to lake water an Al(OH)3 floc is formed, which settles to the bottom and initially form a lid on the sediment surface. The effects of Chironomus
plumosus larvae on sediment nutrient fluxes and P binding-sites in the sediment after addition of Al were tested. C.
plumosus larvae were added to sediment cores in which sediment–water fluxes of nutrients were measured four times. After one month,
the sediment was sectioned with depth and P fractions were measured by sequential chemical extraction. The chironomids created
burrows through the Al layer which caused a significantly increased efflux of P from the Al treated sediment, because the
P had only limited contact to the added Al. The chironomids also affected the P fractions in the sediment by their bioturbating
activity. Thus, they caused increased Al concentrations in the upper part of the Al treated sediment. This created an enhanced
contact between Al and P in the upper 7 cm of the sediment and, as a result, an increased binding of P to Al and a lowered
porewater P. The DIP efflux is therefore expected to be lowered after the initial phase. Al had no effects on the nitrogen
fluxes, but the chironomids enhanced the release, and decreased the release or increased the uptake by the sediments. 相似文献
9.
This study examines 45 cases of trisomy 13 and 59 cases of trisomy 18 and reports an algorithm to identify pregnancies with a fetus affected by trisomy 13 or 18 by a combination of maternal age fetal nuchal translucency (NT) thickness, and maternal serum free β-hCG and PAPP-A at 11–14 weeks of gestation. In this mixed trisomy group the median MoM NT was increased at 2.819, whilst the median MoMs for free β-hCG and PAPP-A were reduced at 0.375 and 0.201 respectively. We predict that with the use of the combined trisomy 13 and 18 algorithm and a risk cut-off of 1 in 150 will for a 0.3% false positive rate allow 95% of these chromosomal defects to be identified at 11–14 weeks. Such algorithms will enhance existing first trimester screening algorithms for trisomy 21. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
10.
The coastal water of northeast Taiwan island, called 'Yin-Yang Hai' for its distinct yellow colour compared with blue offshore water, was investigated from 1989 to 1990 by the authors. Biological study showed the dominant species of plankton to be Copepoda, Cladocera, planktonic eggs and Diatoma. Dominant species of benthos were young crabs, Amphipoda and Annelida, with Amphipoda usually occurring in heavily polluted areas. Heavy metal data showed that the concentration of copper was high. the copper and iron concentration in algae of the intertidal zone was also high. the concentrations of iron and copper in inshore water were also higher than in offshore water. By comparison of the pH and salinity distribution of this area, we conclude that this coastal water has been polluted by acid waste water from coastal industry. the suspended solids concentration in sea water is high. Flocculation occurring at the boundary of fresh and saline water might be a reason for the distinct yellow colour of the water of this area. Further study is required. 相似文献