全文获取类型
收费全文 | 970篇 |
免费 | 20篇 |
国内免费 | 13篇 |
专业分类
安全科学 | 25篇 |
废物处理 | 71篇 |
环保管理 | 87篇 |
综合类 | 112篇 |
基础理论 | 215篇 |
污染及防治 | 353篇 |
评价与监测 | 81篇 |
社会与环境 | 51篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 10篇 |
2022年 | 50篇 |
2021年 | 51篇 |
2020年 | 17篇 |
2019年 | 23篇 |
2018年 | 52篇 |
2017年 | 46篇 |
2016年 | 68篇 |
2015年 | 42篇 |
2014年 | 65篇 |
2013年 | 92篇 |
2012年 | 65篇 |
2011年 | 64篇 |
2010年 | 47篇 |
2009年 | 46篇 |
2008年 | 61篇 |
2007年 | 46篇 |
2006年 | 35篇 |
2005年 | 17篇 |
2004年 | 20篇 |
2003年 | 13篇 |
2002年 | 20篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1972年 | 1篇 |
1965年 | 1篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1957年 | 1篇 |
1956年 | 2篇 |
1940年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有1003条查询结果,搜索用时 234 毫秒
951.
952.
953.
Water quality levels and loads of nutrients transported by the Agüera stream (northern Spain) were studied for a year to assess
the self-purification capacity of this system. The main villages produce an increase of nutrient concentrations and a degradation
of water quality. Nevertheless, the high retention capacity, especially for phosphate, allows the stream to recover its previous
levels of quality after a short reach. The retention of nutrients depends on a complex combination of the flow level, hydrologic
stability and the development of periphytic communities. 相似文献
954.
J. Paula 《Marine Biology》1989,100(3):309-312
Rhythms of larval release of the most abundant decapod crustaceans in the Mira Estuary, Portugal, were observed based on plankton samples made over consecutive ebbing tides during one lunar cycle in June 1986. Most species showed a semi-lunar rhythm of larval release, centered on crepuscular high tides around the quarter moons. The study suggests that the larval-releasing activity is connected to the hour of the high tide rather than to tidal amplitude. 相似文献
955.
Sabine Perch-Nielsen Ana Sesartic Matthias Stucki 《Environmental Science & Policy》2010,13(2):131-140
Greenhouse gas intensity is a ratio comparing the greenhouse gas (GHG) emissions of an activity or economic sector to the economic value it generates. In recent years, many countries have calculated the GHG intensity of their economic sectors as a basis for policy making. The GHG intensity of tourism, however, has not been determined since tourism is not measured as an economic sector in the national accounts. While for tourism-reliant countries it would be useful to know this quantity, a number of difficulties exist in its determination. In this study, we determine the GHG intensity of tourism's value added in Switzerland by means of a detailed bottom-up approach with the main methodological focus on how to achieve consistent system boundaries. For comparison, we calculate the tourism sector's GHG intensity for selected European countries using a simpler top-down approach. Our results show that the Swiss tourism sector is more than four times more GHG intensive than the Swiss economy on average. Of all tourism's sub-sectors, air transport stands out as the sector with by far largest emissions (80%) and highest GHG intensity. The results for other countries make similar, if not as pronounced, patterns apparent. We discuss the results and possible mitigation options against the background of the goal to prevent dangerous climate change. 相似文献
956.
Investigation at the scene of a crime begins with the search for clues. In the case of bloodstains, the most frequently used
reagents are luminol and reduced phenolphthalein (or phenolphthalin that is also known as the Kastle–Meyer colour test). The
limitations of these reagents have been studied and are well known. Household cleaning products have evolved with the times,
and new products with active oxygen are currently widely used, as they are considered to be highly efficient at removing all
kinds of stains on a wide range of surfaces. In this study, we investigated the possible effects of these new cleaning products
on latent bloodstains that may be left at a scene of a crime. To do so, various fabrics were stained with blood and then washed
using cleaning agents containing active oxygen. The results of reduced phenolphthalein, luminol and human haemoglobin tests
on the washed fabrics were negative. The conclusion is that these new products alter blood to such an extent that it can no
longer be detected by currently accepted methods employed in criminal investigations. This inability to locate bloodstains
means that highly important evidence (e.g. a DNA profile) may be lost. Consequently, it is important that investigators are
aware of this problem so as to compensate for it.
相似文献
Fernando Verdú (Corresponding author)Email: |
957.
Sofía Copello Ana I. Dogliotti Domingo A. Gagliardini Flavio Quintana 《Marine Biology》2011,158(6):1247-1257
The study of how and why marine animals distribute themselves at sea has important conservation and management implications
of the species and their habitats. We characterize the oceanographic and biological landscapes of the marine areas used by
breeding Southern Giant Petrels (Macronectes giganteus) at Patagonian colonies and explore inter-sexual and inter-colony differences. The at-sea movements of 16 adults (7 males
and 9 females) were studied by means of satellite telemetry techniques during 1999, 2000, 2002, and 2004 breeding seasons.
Southern Giant Petrels utilized an oceanographic scenario characterized by high productivity, warm sea surface temperature,
and shallow waters. The biological landscape was characterized by a high availability of squid and carrion nearby colonies.
Females spent more time in the shelf break and exploited deeper waters than males. In contrast, males spent more time in coastal
areas and they showed a higher spatial overlap with areas of high squid density than females. Such a prosperous foraging scenario
for both sexes may play a key role in the growth of the breeding population of Southern Giant Petrel Patagonian colonies. 相似文献
958.
Ana Espínola-Arredondo Félix Muñoz-García 《Journal of Environmental Economics and Management》2011,62(3):402-413
This paper analyzes the protection of a common pool resource (CPR) through the management of information. Specifically, we examine an entry deterrence model between an incumbent perfectly informed about the initial stock of a CPR and an uninformed potential entrant. In our model, the appropriation of the CPR by the incumbent reduces both players' future profits from exploiting the resource. In the case of complete information, we show that the incumbent operating in a high-stock common pool overexploits the CPR during the first period since it does not internalize the negative external effect that its first-period exploitation imposes on the entrant's future profits. This inefficiency, however, is absent when the commons totally regenerate across periods. Under incomplete information, we identify an additional form of inefficiency. In particular, the incumbent operating in a low-stock CPR underexploits the resource in order to signal the low available stock to potential entrants, deterring entry. 相似文献
959.
Francisco J. Abascal Manuel Quintans Ana Ramos-Cartelle Jaime Mejuto 《Marine Biology》2011,158(5):1175-1184
Nine individuals of shortfin mako, Isurus oxyrinchus, were tracked in the southeastern Pacific Ocean, off northern Chile, by means of pop-up satellite archival tags. No common
pattern was observed in their trajectories, apart from a movement onshore of all the fish tracked during June–August. The
average estimated rate of movement was of c. 27 km day−1. Data were collected and processed for a total of 341 days, including 33 days for one recaptured fish specimen, allowing
high-resolution archived data to be downloaded. The fish spent most of their time in the mixed layer but undertook dives down
to 888 m. Ambient temperatures ranged between 4.6 and 24.1°C, and the sea surface temperatures recorded ranged from 13.4 to
24.1°C during the study period. No clear diel pattern in depth behavior was observed, but mean vertical distribution was deeper
during the daytime. Moreover, a foraging pattern, consisting of rapid descents below the thermocline followed by slower ascents,
was generally observed during daylight hours. Dissolved oxygen concentration and water temperature seem to be the main factors
affecting the vertical range of the species in the area. This is the first study on electronic tagging of the shortfin mako
in the southeastern Pacific Ocean and covers the longest total tracking period reported so far for this species. 相似文献
960.
Milačič R Zuliani T Oblak T Mladenovič A Ančar JŠ 《Journal of environmental quality》2011,40(4):1153-1161
Electric arc furnace (EAF) steel slag can be used as an alternative high-quality material in road construction. Although asphalts with slag aggregates have been recognized as environmentally acceptable, there is a lack of data concerning the potential leaching of toxic Cr(VI) due to the highly alkaline media of EAF slag. Leaching of selected water extractable metals from slag indicated elevated concentrations of total chromium and Cr(VI). To estimate the environmental impacts of asphalt mixes with slag, leachability tests based on diffusion were performed using pure water and salt water as leaching agents. Compact and ground asphalt composites with natural aggregates, and asphalt composites in which the natural aggregates were completely replaced by slag were prepared. The concentrations of total chromium and Cr(VI) were determined in leachates over a time period of 6 mo. After 1 and 6 mo, the concentrations of some other metals were also determined in the leachates. The results indicated that chromium in leachates from asphalt composites with the addition of slag was present almost solely in its hexavalent form. However, the concentrations were very low (below 25 μg L) and did not represent an environmental burden. The leaching of other metals from asphalt composites with the addition of slag was negligible. Therefore, the investigated EAF slag can be considered as environmentally safe substitute for natural aggregates in asphalt mixes. 相似文献