全文获取类型
收费全文 | 760篇 |
免费 | 3篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 17篇 |
废物处理 | 25篇 |
环保管理 | 68篇 |
综合类 | 402篇 |
基础理论 | 95篇 |
污染及防治 | 113篇 |
评价与监测 | 24篇 |
社会与环境 | 23篇 |
出版年
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 18篇 |
2014年 | 12篇 |
2013年 | 23篇 |
2012年 | 13篇 |
2011年 | 24篇 |
2010年 | 19篇 |
2009年 | 24篇 |
2008年 | 20篇 |
2007年 | 29篇 |
2006年 | 24篇 |
2005年 | 27篇 |
2004年 | 14篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 16篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1990年 | 6篇 |
1985年 | 6篇 |
1975年 | 5篇 |
1967年 | 8篇 |
1966年 | 14篇 |
1965年 | 9篇 |
1964年 | 12篇 |
1963年 | 16篇 |
1962年 | 9篇 |
1961年 | 16篇 |
1959年 | 9篇 |
1958年 | 10篇 |
1957年 | 7篇 |
1956年 | 13篇 |
1955年 | 16篇 |
1954年 | 17篇 |
1939年 | 12篇 |
1938年 | 8篇 |
1937年 | 5篇 |
1934年 | 5篇 |
1933年 | 6篇 |
1932年 | 6篇 |
1930年 | 5篇 |
1929年 | 5篇 |
1926年 | 5篇 |
1914年 | 5篇 |
排序方式: 共有767条查询结果,搜索用时 31 毫秒
51.
Karl Ceulemans Steven Compernolle Jozef Peeters Jean-François Müller 《Atmospheric environment (Oxford, England : 1994)》2010,44(40):5434-5442
BOREAM, a detailed model for the gas-phase oxidation of α-pinene and its subsequent formation of Secondary Organic Aerosol (SOA), is tested against a large set of SOA yield measurements obtained in dark ozonolysis experiments. For the majority of experiments, modelled SOA yields are found to agree with measured yields to within a factor 2. However, the comparisons point to a general underestimation of modelled SOA yields at high temperatures (above 30 °C), reaching an order of magnitude or more in the worst cases, whereas modelled SOA yields are often overestimated at lower temperature (by a factor of about 2). Comparisons of results obtained using four different vapour pressure prediction methods indicate a strong sensitivity to the choice of the method, although the overestimated temperature dependence of the yields is found in all cases. Accounting for non-ideality of the aerosol mixture (based on an adapted UNIFAC method) has significant effects, especially at low yields. Our simulations show that the formation of oligomers through the gas-phase reactions of Stabilised Criegee Intermediates (SCI) with other molecular organic products could increase the SOA yield significantly only at very low relative humidity (below 1%). Further tests show that the agreement between model and measurements is improved when the ozonolysis mechanism includes additional production of non-volatile compounds. 相似文献
52.
53.
Fukushima fallout in Northwest German environmental media 总被引:1,自引:0,他引:1
Traces of short- and long-lived fallout isotopes (131I, 134Cs and 137Cs) were found in environmental samples collected in Northwest Germany (rain water, river sediment, soil, grass and cow milk) from March to May 2011, following the radioactivity releases after the nuclear accident in Fukushima, Japan. The measured concentrations are consistent with reported concentrations in air, amount of rainfall and expected values applying simple radioecological models. The [134Cs]/[137Cs] ratio reported for air (about 1) allows for discrimination between “recent” and “old” 137Cs. Expected 136Cs values fell below the detection limits of the instrumentation, despite large sample masses and long counting times. 相似文献
54.
55.
56.
Amid growing concern about the conservation of renewable natural resources, the process, extent and symptoms of their degradation are examined with specific reference to the Upper Pokhara Valley. Based on a household survey, field observations, informal deliberations and land use analysis, the results of this study reveal that forests and grazing land have been subject to increasing degradation caused by demographic, socioeconomic and institutional factors. The intensity of degradation varies by watershed. In particular, rainfed pakho land on steep slopes is under the severe threat of accelerating soil erosion, despite the construction of terraces. This calls for the formulation of a comprehensive natural resource conservation strategy which should be based on a framework comprising an integrated population control programme, planned land use changes and institutional reforms . 相似文献
57.
Ensuring that new buildings do not interfere with the recreational and protective functions of the natural system and that the buildings will be useful long enough to protect the investment are among long-term solutions to coastal erosion. We propose that coastal cliff management districts be established for management of eroding high relief shorelines. Such districts would include an imminent failure zone, in which bluff retreat is possible at any time; a migration zone, which allows for long-term shoreline retreat; and a stability control zone in which activities affecting bluff erosion are restricted. Procedures are described for delineating these zones based on geomorphic criteria. If these land use controls are implemented, some shorefront development can be accommodated while retaining valuable characteristics of the natural system. 相似文献
58.
The levels of three toxaphene indicator compounds were determined in individual lots of herring, redfish, Greenland halibut and farmed salmon. Concentration levels of the three marine fish species were characterised by a right-skewed frequency distribution whereas residue concentrations in farmed salmon were normally distributed. The toxaphene concentrations in the edible part of redfish, herring and Greenland halibut were found to be positively correlated to the sizes and thus to age. As results show, for representative sampling of a landed catch, not more than 10 individual fishes from typical size classes of a lot are necessary for a pooled sample. 相似文献
59.
60.
Various N fertilizer sources are available for lawn turf. Few field studies, however, have determined the losses of nitrate (NO(3)-N) from lawns receiving different formulations of N fertilizers. The objectives of this study were to determine the differences in NO(3)-N leaching losses among various N fertilizer sources and to ascertain when losses were most likely to occur. The field experiment was set out in a completely random design on a turf typical of the lawns in southern New England. Treatments consisted of four fertilizer sources with fast- and slow-release N formulations: (i) ammonium nitrate (AN), (ii) polymer-coated sulfur-coated urea (PCSCU), (iii) organic product, and (iv) a nonfertilized control. The experiment was conducted across three years and fertilized to supply a total of 147 kg N ha(-1) yr(-1). Percolate was collected with zero-tension lysimeters. Flow-weighted NO(3)-N concentrations were 4.6, 0.57, 0.31, and 0.18 mg L(-1) for AN, PCSCU, organic, and the control, respectively. After correcting for control losses, average annual NO(3)-N leaching losses as a percentage of N applied were 16.8% for AN, 1.7% for PCSCU, and 0.6% for organic. Results indicate that NO(3)-N leaching losses from lawn turf in southern New England occur primarily during the late fall through the early spring. To reduce the threat of NO(3)-N leaching losses, lawn turf fertilizers should be formulated with a larger percentage of slow-release N than soluble N. 相似文献