全文获取类型
收费全文 | 242篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 5篇 |
废物处理 | 13篇 |
环保管理 | 14篇 |
综合类 | 128篇 |
基础理论 | 33篇 |
环境理论 | 2篇 |
污染及防治 | 34篇 |
评价与监测 | 4篇 |
社会与环境 | 12篇 |
出版年
2021年 | 3篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 6篇 |
2011年 | 9篇 |
2010年 | 4篇 |
2009年 | 9篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2003年 | 3篇 |
2002年 | 10篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 10篇 |
1998年 | 4篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1974年 | 3篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1967年 | 4篇 |
1966年 | 5篇 |
1965年 | 3篇 |
1964年 | 8篇 |
1963年 | 2篇 |
1962年 | 5篇 |
1961年 | 4篇 |
1960年 | 3篇 |
1959年 | 5篇 |
1958年 | 2篇 |
1957年 | 4篇 |
1956年 | 5篇 |
1955年 | 5篇 |
1954年 | 7篇 |
1953年 | 2篇 |
1952年 | 4篇 |
1948年 | 2篇 |
1943年 | 2篇 |
1941年 | 3篇 |
1936年 | 3篇 |
1930年 | 2篇 |
1928年 | 3篇 |
排序方式: 共有245条查询结果,搜索用时 46 毫秒
31.
32.
Although the implementation of wastewater treatment plants (WWTP) has dramatically increased the quality of surface waters in urbanized areas, WWTPs can still discharge noticeable amounts of solutes and particles to recipient streams. Although the fate of WWTP nutrients has received considerable attention, transport and in-stream transformation of sewage-derived particulate organic matter (SDPOM) have not. To investigate the transport and transformation of SDPOM in recipient streams, we experimentally injected fluorescently labeled SDPOM into a headwater stream and tracked its downstream fate at baseflow. Most SDPOM disappeared from the streamwater within a 160-m long reach with an average deposition velocity of 0.14 mm s(-1). We further coupled hydrometric measurements of specific water fluxes through the streambed interface with a mixing model to estimate streambed oxygen removal, and found significantly higher oxygen removal in the deposition (0.75 g O2 m(-2) d(-1)) than in the downstream post-deposition (0.36 g O2 m(-2) d(-1)) subreach. Contrary to our expectations, we did not detect any apparent effect of SDPOM deposition on streambed clogging. Our results show the capacity of a recipient stream to retain SDPOM and to reduce its downstream export, and thus contribute to a better understanding of ecosystem services of human-altered streams. 相似文献
33.
34.
There is a general consensus that most of today’s nonvenomous snakes are descendants of venomous snakes that lost their venomous
capabilities secondarily. This implies that the evolutionary history of venomous snakes and their venom apparatus should be
older than the current evidence from the fossil record. We compared some of the oldest-known fossil snake fangs from the Lower
Miocene of Germany with those of modern viperids and elapids and found their morphology to be indistinguishable from the modern
forms. The primary function of recent elapid and viperid snake fangs is to facilitate the extremely rapid, stab-like application
of highly toxic venoms. Our findings therefore indicate that the other components of the venom-delivery system of Early Miocene
vipers and elapids were also highly developed, and that these snakes used their venom in the same way as their modern relatives.
Thus, the fossil record supports the view that snakes used their venoms to rapidly subdue prey long before the mid-Tertiary
onset of the global environmental changes that seem to have supported the successful radiation of venomous snakes. 相似文献
35.
Monitoring of iodinated X-ray contrast media in surface water 总被引:1,自引:0,他引:1
A monitoring programme was carried out in order to determine iodinated X-ray contrast media (ICM) in the River Danube and to investigate the raw water quality for drinking water production at Langenau waterworks. The study revealed that the maximum concentrations of ICM (over 500 ng l(-1) for diatrizoic acid and iopamidol) were found in 2h-composite samples taken from the downstream of the Ulm/Neu-Ulm metropolitan area. By means of a concentration profile over one month the highest ICM concentrations were observed on weekdays. The extended data evaluation with principal component analysis shows that the upstream and downstream samples had different pattern of variations in ICM concentration and also demonstrates a clear change in ICM composition by the discharge of municipal wastewater. In addition to load profiles of ICM, time-dependent plots of principal component 1 exhibited peaks, indicating a short-term discharge of ICM between the two sampling sites. In conclusion, a point source for ICM contamination between the sampling sites in Ulm upstream and Leipheim downstream seems to be the reasonable explanation for peak ICM concentrations. Due to the observed high variations of ICM concentrations in river, the evaluation of natural waters by means of a single analysis is not representative. 相似文献
36.
37.
Huber Florian Korotenko Ekaterina Šyc Michal Fellner Johann 《Journal of Material Cycles and Waste Management》2021,23(1):394-401
Journal of Material Cycles and Waste Management - Bottom ash is the main solid residue from municipal solid waste incineration (MSWI). The material can be utilised in the construction industry but... 相似文献
38.
Summary. Analysis of South-East Asian troidine swallowtails revealed high variability in the content of aristolochic acids among individuals.
The presence or absence of these compounds depends on the Aristolochia species available as food plant for the larvae. Only one plant species (Aristolochia philippinensis) contained a high concentration of aristolochic acids, while other species from various localities contained none or only
marginal amounts. Whether aristolochic acids have a distinct function in chemical defense of these swallowtails is still an
open question.
Received 11 December 2000; accepted 4 August 2001. 相似文献
39.
40.