全文获取类型
收费全文 | 2090篇 |
免费 | 10篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 39篇 |
废物处理 | 64篇 |
环保管理 | 121篇 |
综合类 | 754篇 |
基础理论 | 379篇 |
环境理论 | 7篇 |
污染及防治 | 563篇 |
评价与监测 | 93篇 |
社会与环境 | 83篇 |
灾害及防治 | 3篇 |
出版年
2021年 | 15篇 |
2019年 | 15篇 |
2018年 | 32篇 |
2017年 | 44篇 |
2016年 | 41篇 |
2015年 | 38篇 |
2014年 | 47篇 |
2013年 | 98篇 |
2012年 | 48篇 |
2011年 | 85篇 |
2010年 | 61篇 |
2009年 | 66篇 |
2008年 | 95篇 |
2007年 | 96篇 |
2006年 | 71篇 |
2005年 | 70篇 |
2004年 | 48篇 |
2003年 | 51篇 |
2002年 | 56篇 |
2001年 | 61篇 |
2000年 | 43篇 |
1999年 | 32篇 |
1998年 | 23篇 |
1997年 | 22篇 |
1996年 | 21篇 |
1995年 | 21篇 |
1994年 | 34篇 |
1993年 | 14篇 |
1992年 | 16篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 14篇 |
1984年 | 16篇 |
1982年 | 14篇 |
1981年 | 20篇 |
1969年 | 15篇 |
1968年 | 13篇 |
1967年 | 20篇 |
1966年 | 27篇 |
1965年 | 38篇 |
1964年 | 23篇 |
1963年 | 34篇 |
1962年 | 26篇 |
1961年 | 33篇 |
1960年 | 24篇 |
1959年 | 23篇 |
1958年 | 14篇 |
1957年 | 25篇 |
1956年 | 18篇 |
1955年 | 16篇 |
排序方式: 共有2106条查询结果,搜索用时 46 毫秒
811.
812.
Evolutionary history of tRNA is studied by comparative sequence analysis of two specified tRNA's at various phylogenetic levels and of tRNA families within four different species. Criteria are developed that allow 1) to distinguish between convergent and divergent evolution, 2) to determine the mechanism of divergence and 3) to estimate the degree of randomization of the variable parts of the sequences. The conclusion of these investigations is that tRNA's represent ancient molecules that existed in the form of a mutant distribution prior to their integration into genomes. 相似文献
813.
Sílvia Bofill-Mas Byron Calgua Pilar Clemente-Casares Giuseppina La Rosa Marcello Iaconelli Michele Muscillo Saskia Rutjes Ana Maria de Roda Husman Andreas Grunert Ingeburg Gräber Marco Verani Annalaura Carducci Miquel Calvo Peter Wyn-Jones Rosina Girones 《Food and environmental virology》2010,2(2):101-109
The presence of human adenoviruses (HAdV) in recreational water might cause disease in the population upon exposure. HAdV detected by PCR could also serve as indicators of the virological water quality. In order to assess the applicability of HAdV to the evaluation of the faecal contamination in European bathing waters, a real-time quantitative PCR assay was used for the quantification of HAdV in 132 samples collected from 24 different recreational marine and freshwater sites in nine European countries. Selected samples presenting positive nested PCR results for HAdV were analyzed using quantitative PCR and 80 samples from a total of 132 produced quantitative results with mean values of 3.2 × 102 per 100 ml of water, being human adenovirus 41 the most prevalent serotype between the samples where adenovirus was typified. HAdV were quantified in samples from all 15 surveillance laboratories. Statistical analysis showed no homogeneous linear relation between HAdV and E. coli, intestinal enterococci or somatic coliphages concentrations in the tested samples when considering all the data together. Significant correlations between HAdV and at least one of the other indicators were observed only when data from individual laboratories were considered. The quantification of HAdV may provide complementary information in relation to the use of bacterial standards in the control of water quality in bathing water. 相似文献
814.
Comparison of VOC and ammonia emissions from individual PVC materials, adhesives and from complete structures 总被引:1,自引:0,他引:1
Emission rates of volatile organic compounds (VOCs) and ammonia measured from six PVC materials and four adhesives in the laboratory were compared to the emission rates measured on site from complete structures. Significantly higher specific emission rates (SERs) were generally measured from the complete structures than from individual materials. There were large differences between different PVC materials in their permeability for VOCs originating from the underlying structure. Glycol ethers and esters from adhesives used in the installation contributed to the emissions from the PVC covered structure. Emissions of 2-ethylhexanol and TXIB (2,2,4-trimethyl-1,3-pentanediol diisobutyrate) were common. High ammonia SERs were measured from single adhesives but their contribution to the emissions from the complete structure did not appear as obvious as for VOCs. The results indicate that three factors affected the VOC emissions from the PVC flooring on a structure: 1) the permeability of the PVC product for VOCs, 2) the VOC emission from the adhesive used, and 3) the VOC emission from the backside of the PVC product. 相似文献
815.
816.
L. Maunula P. Klemola A. Kauppinen K. Söderberg T. Nguyen T. Pitkänen S. Kaijalainen M. L. Simonen I. T. Miettinen M. Lappalainen J. Laine R. Vuento M. Kuusi M. Roivainen 《Food and environmental virology》2009,1(1):31-36
In Nokia city about 450,000 l of treated sewage water was for 2 days allowed to run into the drinking water supplies of the
city due to a personal error of one employee. Within the next 5 weeks about 1,000 people sought care at the municipal health
centre or regional hospital because of gastroenteritis. Here we report the results of viral analyses performed by gene amplification
assays from the earliest water and sewage samples as well as from close to 300 patient samples. The contaminating treated
sewage was shown to harbour several enteric viruses known to cause acute gastroenteritis. Likewise, the drinking water sample
was positive for noro-, astro-, rota-, entero- and adenoviruses. Noroviruses were also found in 29.8% of stool samples from
affected patients, while astro-, adeno-, rota- and enteroviruses were detected in 19.7, 18.2, 7.5 and 3.7% of the specimens,
respectively.
An erratum to this article can be found at 相似文献
817.
OBJECTIVE: Previous research has shown that elderly and disabled travelers using Special Transportation Services (STS) are injured without being involved in a vehicle crash. In order to estimate the true costs for these vehicle-related injuries, the focus needs to be adjusted towards an incident/traveler-oriented perspective. The aim of the project was thus to utilize such a perspective, in order to make a best estimation of the true costs for injury incidents, related to STS in Sweden. METHODS: In order to address the chosen perspective, a mixed-method approach was used, involving quantitative as well as qualitative research methods applied on four different sets of data, the hospital-based material (n=32), two sets of STS material (n=127), and interview-based material (n=1,000). RESULTS: The results showed that the injury incidence rate in STS is considerable, i.e., 3.2 per 100,000 trips (ranging from 1.5-1.9 in STS taxis and 3.6-5.6 in STS special vehicles). However, this high incidence rate is not due to road traffic crashes, but to non-collision injury incidents involving elderly and frail passengers, easily sustaining injuries from minor to moderate external violence. Typically, this violence is affecting an older female STS user, while entering and exiting the vehicle. The true costs were estimated to be $35 million per annum or $2.6 per trip. CONCLUSION: Future injury prevention measures should thus focus on safety in entering and exiting procedures. 相似文献
818.
Human serum and plasma from Sweden (n=17), the United Kingdom (the UK) (n=13) and Australia (n=40) were analyzed by high performance liquid chromatography coupled to mass spectrometry. The objective was to identify different perfluorooctane sulfonate (PFOS) isomers. Similar isomer patterns typical for the electrochemical fluorination (ECF) process were found for all samples. The linear PFOS (L-PFOS) was the major isomer found (58-70%) followed by the monosubstituted PFOS isomers 1/6-CF(3)-PFOS (18-22%) and 3/4/5-CF(3)-PFOS (13-18%). Disubstituted isomers were also detected. The percentage of L-PFOS found in the serum and plasma samples was lower compared to a standard PFOS product (76-79%). The pattern of PFOS isomers in human serum and plasma may be suggestive concerning potential isomeric discrimination since PFOS is only produced by ECF. Possibilities for such isomer discrimination are discussed. Significant higher content of L-PFOS (68%) in Swedish samples compared to Australia and the UK (59%) was also found, which may suggest differences in exposure sources for humans. 相似文献
819.
Peter Viebahn Daniel Vallentin Samuel H?ller Manfred Fischedick 《Mitigation and Adaptation Strategies for Global Change》2012,17(6):707-730
The study presents the results of an integrated assessment of carbon capture and storage (CCS) in the power plant sector in Germany, with special emphasis on the competition with renewable energy technologies. Assessment dimensions comprise technical, economic and environmental aspects, long-term scenario analysis, the role of stakeholders and public acceptance and regulatory issues. The results lead to the overall conclusion that there might not necessarily be a need to focus additionally on CCS in the power plant sector. Even in case of ambitious climate protection targets, current energy policy priorities (expansion of renewable energies and combined heat and power plants as well as enhanced energy productivity) result in a limited demand for CCS. In case that the large energy saving potential aimed for can only partly be implemented, the rising gap in CO2 reduction could only be closed by setting up a CCS-maximum strategy. In this case, up to 22% (41 GW) of the totally installed load in 2050 could be based on CCS. Assuming a more realistic scenario variant applying CCS to only 20 GW or lower would not be sufficient to reach the envisaged climate targets in the electricity sector. Furthermore, the growing public opposition against CO2 storage projects appears as a key barrier, supplemented by major uncertainties concerning the estimation of storage potentials, the long-term cost development as well as the environmental burdens which abound when applying a life-cycle approach. However, recently, alternative applications are being increasingly considered?Cthat is the capture of CO2 at industrial point sources and biomass based energy production (electricity, heat and fuels) where assessment studies for exploring the potentials, limits and requirements for commercial use are missing so far. Globally, CCS at power plants might be an important climate protection technology: coal-consuming countries such as China and India are increasingly moving centre stage into the debate. Here, similar investigations on the development and the integration of both, CCS and renewable energies, into the individual energy system structures of such countries would be reasonable. 相似文献
820.
Effects of ethylenediurea and ozone on the antioxidative systems in beans (Phaseolus vulgaris L.) 总被引:1,自引:0,他引:1
Brunschön-Harti S Fangmeier A Jäger HJ 《Environmental pollution (Barking, Essex : 1987)》1995,90(1):95-103
To study the biochemical mechanism of EDU protection against ozone injury, peroxidase, ascorbate-dependent peroxidase, and catalase activities, and the contents of ascorbic acid, dehydroascorbic acid, malondialdehyde and soluble protein were measured in Phaseolus vulgaris L. cv. Lit exposed to ozone and ethylenediurea (EDU) in open-top chambers. Plants not treated with EDU showed foliar bronzing due to ozone, while EDU-treated plants were not affected. EDU application modified the reaction of biochemical parameters to ozone. Soluble protein content was elevated by EDU. Peroxidase activity increased with ozone exposure in untreated plants only, while ascorbate-dependent peroxidase activity was lower in EDU treated plants. Catalase activity decreased in EDU-untreated plants. The ratio of ascorbic acid to dehydroascorbic acid was significantly increased in EDU treated plants. These results suggest that EDU might induce ascorbic acid synthesis and therefore provide the plant with a very potent antioxidant. Or the content of hydrogen peroxide was reduced due to other unknown processes and caused a delay in foliar senescence, regardless of whether these processes were ozone-induced or due to natural aging processes. 相似文献