全文获取类型
收费全文 | 620篇 |
免费 | 4篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 11篇 |
环保管理 | 31篇 |
综合类 | 354篇 |
基础理论 | 90篇 |
污染及防治 | 104篇 |
评价与监测 | 23篇 |
社会与环境 | 13篇 |
灾害及防治 | 1篇 |
出版年
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 9篇 |
2013年 | 19篇 |
2012年 | 8篇 |
2011年 | 24篇 |
2010年 | 14篇 |
2009年 | 15篇 |
2008年 | 21篇 |
2007年 | 18篇 |
2006年 | 6篇 |
2005年 | 15篇 |
2004年 | 16篇 |
2003年 | 17篇 |
2002年 | 13篇 |
2001年 | 7篇 |
1999年 | 13篇 |
1998年 | 15篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1975年 | 5篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1970年 | 8篇 |
1967年 | 9篇 |
1966年 | 5篇 |
1965年 | 12篇 |
1964年 | 6篇 |
1963年 | 13篇 |
1962年 | 11篇 |
1961年 | 9篇 |
1960年 | 10篇 |
1959年 | 14篇 |
1958年 | 9篇 |
1957年 | 8篇 |
1956年 | 10篇 |
1955年 | 8篇 |
1954年 | 6篇 |
1953年 | 6篇 |
1952年 | 5篇 |
1951年 | 6篇 |
1932年 | 6篇 |
1930年 | 5篇 |
1928年 | 5篇 |
1926年 | 6篇 |
1914年 | 6篇 |
1913年 | 10篇 |
排序方式: 共有629条查询结果,搜索用时 672 毫秒
221.
Developing a Monitoring Protocol for Visitor-Created Informal Trails in Yosemite National Park,USA 总被引:1,自引:0,他引:1
Informal trails created or perpetuated by visitors is a management challenge in many protected natural areas such as Yosemite
National Park. This is a significant issue as informal trail networks penetrate and proliferate into protected landscapes
and habitats, threatening ecological integrity, aesthetics, and visitor experiences. In order to develop effective strategies
for addressing this problem under an adaptive management framework, indicators must be developed and monitoring protocol must
be established to gather timely and relevant data about the condition, extent, and distribution of these undesired trail segments.
This article illustrates a process of developing and evaluating informal trail indicators for meadows in Yosemite Valley.
Indicator measures developed in past research were reviewed to identify their appropriateness for the current application.
Information gaps in existing indicator measures were addressed by creating two new indices to quantify the degree of informal
trailing based on its land fragmentation effects. The selected indicator measures were applied to monitoring data collected
between 2006 and 2008. The selected measures and indices were evaluated for their ability to characterize informal trail impacts
at site and landscape scales. Results demonstrate the utility of indicator measures in capturing different characteristics
of the informal trail problem, though several metrics are strongly related to each other. The two fragmentation indices were
able to depict fragmentation without being too sensitive to changes in one constituent parameter. This study points to the
need for a multiparameter approach to informal trail monitoring and integration with other monitoring data. Implications for
monitoring programs and research are discussed. 相似文献
222.
Britta Grote Wilhelm Hagen Marek R. Lipinski Hans M. Verheye Erling K. Stenevik Werner Ekau 《Marine Biology》2011,158(5):1005-1017
Cape hakes, Merluccius paradoxus and M. capensis, are important gadoid fish that are commercially harvested in the Benguela Current system off Namibia and South Africa. The
aim of this study was to elucidate the nutritional condition and feeding preferences of their larvae. Hake eggs and larvae
were sampled in austral spring of two consecutive years, 2007 and 2008, off the west coast of South Africa. They were identified
to species using genetics, and total lipid content and fatty acid (FA) composition were analysed for each individual egg and
larva to compare the condition of different early life stages of both hake species. Higher abundances of M. paradoxus eggs and larvae were consistently found compared to M. capensis. In both species, eggs contained wax esters (WE) and had significantly higher lipid content per dry mass than larvae. Lipid
content as well as FA composition changed with the developmental stage of larvae. Quantities of essential fatty acid (EFA)
increased with feeding of larvae due to dietary lipid incorporation. In 2007, yolk-sac larvae contained significantly lower
total lipids than in 2008. It is argued that this was due to reduced lipid transfer by the spawning females to the eggs. These
findings indicate that maternal effects are important in determining condition of hake larvae and that this may have an effect
on their survival and subsequent recruitment. 相似文献
223.
224.
Frías-Espericueta MG Osuna-López JI Jiménez-Vega MA Castillo-Bueso D Muy-Rangel MD Rubio-Carrasco W López-López G Izaguirre-Fierro G Voltolina D 《Environmental monitoring and assessment》2011,182(1-4):133-139
The increasing order of the mean concentrations of Cd, Cu, and Zn in the tissues of Mugil cephalus of seven coastal lagoons of Sinaloa State (NW Mexico) was liver > gills > muscle, while for Pb it was gills > muscle ≥ liver. There were no differences between the mean concentrations of Cd and Pb of the three tissues determined in the samples of the seven lagoons and, although there were some significant differences, there was no indication of a latitude-related trend in the distribution of Cu and Zn: the Cu content of the muscle tended to be higher in the northern than in the southern lagoons, although in the case of the gills the highest and lowest mean values indicated an opposite trend, with the highest and lowest values in one southern and one northern lagoon. In the case of the liver, there were no differences and no indication of a regional trend. There were no differences in the mean Zn contents of muscle and gills; in the case of the liver, one of the lagoons of the central part of the state had a significantly higher value than one of the southern lagoons and all the rest had similar values. In addition, there was no clear indication of season-related differences in any of the three tissues. According to our results, the metal contents of the muscle of this species are not of concern for human health, since the allowable ingestion would be in the order of 0.9 kg/day. 相似文献
225.
Werner Theobald 《Environmental Sciences Europe》2003,15(4):262-272
Environmental assessment is a domain of economic, legal and natural sciences. Emotional aspects of environmental assessment are widely undiscussed. However, the consideration of the emotional relationship with nature is an important prerequisite for the acceptance of nature conservation. In connection with the current discussion on aspects of environmental ethics and aesthetics of nature, philosophy has been considering the emotional relationship with nature. However, the analysis of these philosophical approaches shows that they are not able to reconstruct that relationship appropriately. This paper tries to give a new answer. It interprets the emotional relationship with nature as a relic of mythic thinking. 相似文献
226.
Most studies on insect sperm motility have been conducted in vitro using artificial environments outside the animal’s body.
Only little is known about the function of motile insect sperm at different sites within the male or female genital tracts.
We dissected genital tracts of female rove beetles (Drusilla canaliculata) to show that spermatozoa use their own motility to migrate from the spermatophore into the spermatheca. Our dissection method
allowed direct observation and filming of the spermathecal filling process inside the female’s genital tract. Spermatozoa
were found to enter the spermatheca individually, sometimes in groups of two or three. Although exhibiting only weak motility
and no progressive motion in buffer solution, the spermatozoa inside the female show vigorous lashing and reach an average
velocity of 47.5 μm s−1. To gain mobility and speed, the spermatozoa likely utilize the relatively small diameter of the spermathecal duct to push
themselves off the duct walls, rather than swimming freely in seminal fluid. The spermatozoa (approximately 1,250 μm) are
considerably longer than the distance they have to travel along the spermathecal duct (approximately 800 μm). Our study provides
the first direct observation of active sperm migration within the female of an insect stressing the importance of the genital
tract as a prerequisite for functional sperm motility. 相似文献
227.
About 17 years after the Chernobyl accident, lichen samples were collected in an alpine region in Austria (Bad Gastein), which was heavily contaminated by the Chernobyl fallout. Measured 137Cs activity concentrations in selected lichens (Cetraria islandica, Cetraria cucullata, and Cladonia arbuscula) ranged from 100 to 1100 Bq kg(-1) dry weight, depending on lichen species and sampling site. Ecological half-lives for 137Cs in different lichen samples, obtained by comparison with earlier measurements of the same lichen species at the same site, ranged from 2 to 6 years, with average values between 3 and 4 years. Comparison with earlier studies indicated that ecological half-lives hardly changed during the last 10 years, suggesting that ecological clearance mechanisms (e.g. washout or soil transfer) did not vary substantially at the selected sampling area. 相似文献
228.
Bernhard Freyer Valentina Aversano-Dearborn Georg Winkler Sina Leipold Harald Haidl Karl Werner Brand Michael Rosenberger Thomas Wallnig 《Journal of Agricultural and Environmental Ethics》2018,31(5):559-582
For decades there has been a controversial debate over how far religious faith communities are specifically engaged in ecological practices (EP). Therefore we studied four Austrian and two German Benedictine monasteries religious ethics and spirituality as a means of a driving force for initiating EP. We draw upon theories of organizational learning processes and capacity-building of sustainability to interpret our empirical findings. The majority of monasteries are highly engaged in EP, initiated either as an outcome of individual activities or through a specific mostly informally acting group, but rarely an organizationally or systematically integrated goal of the monasteries, or a focus of capacity building. Monasteries follow a technical and economic decision-making process in implementing EP. Spirituality plays a limited role in the initiation of EP. The environment of monasteries–acceptance or critique against ecological practices–influences the monasteries decisions. Institutionalization of ecological practices into the monasteries organizational structure is rare. 相似文献
229.
Janine W. Y. Wong Bettina Hitzfeld Michael Zimmermann Inge Werner Benoît J. D. Ferrari 《Environmental Sciences Europe》2018,30(1):49
Background
Soil is one of our most important resources and fulfills many ecological functions such as storage and filtration of water and nutrients, transformation of chemical compounds and nutrients, biomass production, and carbon storage. Such soil functions support ecosystem services provided by soils, which need to be protected to protect soil fertility. However, European soils often contain elevated concentrations of contaminants, putting biodiversity of soil organisms as well as the ecological functions and services at risk. To promote soil ecotoxicology in Switzerland, the Swiss Centre for Applied Ecotoxicology together with the Federal Office for Environment and the Federal Office for Agriculture organized a stakeholder workshop on 7 June 2018 with participants from research, governmental bodies, and associations. One goal of this workshop was to inform participants about currently available risk assessment approaches for soil, the soil risk assessment for plant protection products in Europe, available bioassays and bioindicators, and results of research projects on soil contaminants in Switzerland. Another goal was to discuss the needs for research in soil ecotoxicology in Switzerland and to identify next steps, potential projects, and future collaborations.Results
The main needs identified during the workshop were the establishment of (bio)indicators to measure soil fertility, functional parameters to determine soil functions, and the preservation of soil biodiversity. Another priority listed was the formation of a working group, which addresses the issue of the development of environmental quality standards for soil. The need for experimental field sites for implementing and testing new approaches or tools for assessing soil quality was also discussed.Conclusion
The next steps planned are two workshops with national and international experts in soil ecotoxicology to develop a soil monitoring concept for Switzerland and to find suitable bioindicators to evaluate soil fertility. Additionally, a literature review will be performed summarizing the current ecotoxicological state of the art with regard to the development of bioindicators in relation to the monitoring of plant protection products in Swiss soil, to evaluate their effects on soil fertility. Furthermore, all attendees agreed on the need for annual meetings or workshops where experts can present scientific results, participants can exchange information, and future projects and collaborations can be developed.230.
Zurbrügg C Gfrerer M Ashadi H Brenner W Küper D 《Waste management (New York, N.Y.)》2012,32(11):2126-2133
According to most experts, integrated and sustainable solid waste management should not only be given top priority, but must go beyond technical aspects to include various key elements of sustainability to ensure success of any solid waste project. Aside from project sustainable impacts, the overall enabling environment is the key feature determining performance and success of an integrated and affordable solid waste system. This paper describes a project-specific approach to assess typical success or failure factors. A questionnaire-based assessment method covers issues of: (i) social mobilisation and acceptance (social element), (ii) stakeholder, legal and institutional arrangements comprising roles, responsibilities and management functions (institutional element); (iii) financial and operational requirements, as well as cost recovery mechanisms (economic element). The Gianyar Waste Recovery Project in Bali, Indonesia was analysed using this integrated assessment method. The results clearly identified chief characteristics, key factors to consider when planning country wide replication but also major barriers and obstacles which must be overcome to ensure project sustainability. The Gianyar project consists of a composting unit processing 60tons of municipal waste per day from 500,000 inhabitants, including manual waste segregation and subsequent composting of the biodegradable organic fraction. 相似文献