全文获取类型
收费全文 | 423篇 |
免费 | 6篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 12篇 |
废物处理 | 37篇 |
环保管理 | 35篇 |
综合类 | 55篇 |
基础理论 | 88篇 |
污染及防治 | 134篇 |
评价与监测 | 39篇 |
社会与环境 | 31篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 3篇 |
2022年 | 13篇 |
2021年 | 20篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 22篇 |
2017年 | 15篇 |
2016年 | 20篇 |
2015年 | 10篇 |
2014年 | 18篇 |
2013年 | 41篇 |
2012年 | 25篇 |
2011年 | 25篇 |
2010年 | 17篇 |
2009年 | 34篇 |
2008年 | 19篇 |
2007年 | 18篇 |
2006年 | 17篇 |
2005年 | 23篇 |
2004年 | 10篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1973年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有432条查询结果,搜索用时 109 毫秒
411.
412.
Mirna H. R. Seleghim Simone P. de Lira Patrícia T. Campana Roberto G. S. Berlinck Marcio R. Custódio 《Marine Biology》2007,150(5):967-975
Ascidians are a notable source of nitrogen-bearing secondary metabolites with a wide range of biological activities. Although
many biologically active compounds have been isolated from ascidians, it is often unclear whether the animal or associated
microbial symbionts such as bacteria or fungi are the true biosynthetic source of the metabolites. We have addressed the question
of the biosynthetic source of the alkaloids granulatimide and isogranulatimides by localizing these compounds within the ascidian.
In this work, we demonstrate that granulatimide is stored in Didemnum
granulatum tunic bladder cells. Analysis by confocal fluorescence microscopy at the granulatimide emission range indicated the presence
of fluorescent cells as highly vacuolated cells found dispersed in the ascidian tunic. Since this is the most exposed ascidian
tissue, it is possible that these alkaloids may have a protective role, either as sunscreens and/or as feeding deterrents. 相似文献
413.
Clara Musa Roberta Licheri Antonio Mario Locci Roberto Orrù Giacomo Cao Miguel Angel Rodriguez Lucyna Jaworska 《Journal of Cleaner Production》2009,17(9):877-882
The conventional (hot pressing or HP) and the novel (spark plasma sintering or SPS) consolidation techniques were compared when processing Ti–Al2O3–TiC powders obtained by self-propagating high-temperature synthesis (SHS). It was found that the two different methods are able to produce similar materials, in some cases (Vickers hardness and wear rate) slightly better for SPSed samples. However, SPS does not need sintering temperatures as high as HP to obtain fully dense products. Most significantly, processing times were strongly reduced when adopting the SPS technique instead of HP, i.e. 4–7 min and about 5 h, respectively. Finally, when the total energies required during each SPS or HP experiment were compared, it was found that the use of the SPS technology allowed for an energy saving in the order of 90–95%. This fact makes SPS significantly advantageous from environmental and economical points of view compared to HP. 相似文献
414.
Félix-Valenzuela Leticia Molina-Chavarria Alejandro Enríquez-Hernández Carmen Itzé Bolado-Martínez Enrique Durazo-Arvizu María de los Ángeles Dórame-Castillo Roberto Cano-Rangel Manuel Alberto Mata-Haro Verónica 《Food and environmental virology》2020,12(4):355-360
Food and Environmental Virology - Norovirus (NoV) is an important etiological agent of diarrhea in children and adults. In Mexico, NoV screening is not routinely performed. NoV is highly infectious... 相似文献
415.
Roberto E. Barrios 《Disasters》2014,38(2):329-350
A number of recent studies on disaster reconstruction have focused on the concept of community resilience and its importance in the recovery of communities from collective trauma. This article reviews the contributions the anthropological literature and the ethnographic case studies of two post‐Hurricane Mitch housing reconstruction sites make to the theorising of community and resilience in post‐disaster reconstruction. Specifically, the article demonstrates that communities are not static or neatly bounded entities that remain constant before, during and after a disaster; rather, communities take on shape and qualities depending on the relationships in which they engage with government agencies and aid organisations before and after disasters. Consequently, the article argues that definitions of community resilience and disaster mitigation programmes must take the emergent and relational nature of communities into account in order to address the long‐term causes and impacts of disasters. 相似文献
416.
Saskia Van Gaever Leon Moodley Francesca Pasotti Marco Houtekamer Jack J. Middelburg Roberto Danovaro Ann Vanreusel 《Marine Biology》2009,156(6):1289-1296
We report the results of a detailed investigation on the trophoecology of two dominant meiofaunal species at the Håkon Mosby Mud Volcano (HMMV), a deep-sea cold methane-venting seep. Analyses of fatty acids (FAs) and their stable carbon isotopes were used to determine the importance of chemosynthetic nutritional pathways for the dominant copepod species (morphologically very similar to Tisbe wilsoni) inhabiting the volcano’s centre and the abundant nematode Halomonhystera disjuncta from the surrounding microbial mats. The strong dominance of bacterial biomarkers (16:1ω7c, 18:1ω7c and 16:1ω8c) coupled with their individual light carbon isotopes signatures (δ13C ranging from ?52 to ?81‰) and the lack of symbiotic relationships with prokaryotes (as revealed by molecular analyses and fluorescent in situ hybridisation) indicated that chemosynthetically derived carbon constitutes the main diet of both species. However, the copepod showed a stronger reliance on the utilisation of methanotrophic bacteria and contained polyunsaturated FAs of bacterial origin (20:5ω3 and 22:6ω3 with isotope signatures δ13C < ?80‰). Instead, the FA profiles of H. disjuncta suggested that sulphide-oxidising bacteria constituted the main diet of this nematode. Therefore, HMMV can be regarded as a persistent deep-sea cold seep, allowing a chemosynthesis-based trophic specialisation by the dominant meiofaunal species inhabiting its sediments. The present investigation, through the determination of the fatty acid profiles, provides the first evidence for trophic specialisation of meiofauna associated with sub-habitats within a cold seep. 相似文献
417.
Munawar Ali Junli Zhang Roberto Raga Maria Cristina Lavagnolo Alberto Pivato Xu Wang Yuanyuan Zhang Raffaello Cossu Dongbei Yue 《Frontiers of Environmental Science & Engineering》2018,12(3):5
418.
Ramón Alberto Díaz-Varela Roberto Colombo María Silvia Calvo-Iglesias Antonio Tagliaferri 《Ecological modelling》2010,221(4):621-392
There is general agreement in literature that Alpine vegetation belt ecotones have shown a trend of upward migration in the last few decades. Despite the potential of such shifts as indicators of global change effects in mountain ecosystems, there are relatively few works focused on their assessment in a systematic and spatially explicit way. In this work our aim is to quantify the altitudinal shifts and analyse the spatial pattern dynamics of mountain ecotones. We developed a novel procedure to delineate the current and former state of three characteristic mountain ecotones, which we formalised as forest, tree and tundra lines. Our approach is based on the recognition of altitudinal extreme outposts identified with ecotone locations at a slope scale. The integration of multi-temporal datasets allows the identification and quantification of altitudinal advances and retreats in the outpost locations for a given period. We tested the method in a section of the Italian Alps for the period 1957-2003. Results show a general trend of an increase in altitude for the three ecotones, despite the occurrence of occasional decreases. We estimate decadal altitude increments of 25 m for forest line, 13 m for treeline and 11 m for tundra line. We also identified changes in ecotone spatial morphology between the two dates, with significant implications in connectivity and colonisation dynamics. 相似文献
419.
Nicola Saino Maria Romano Diego Rubolini Manuela Caprioli Roberto Ambrosini Mauro Fasola 《Behavioral ecology and sociobiology》2010,64(11):1813-1821
Parental decisions can determine offspring experience of environmental conditions. Such ‘maternal’ effects act both before and after hatching via, e.g., egg quality or the social milieu predisposed by parents. Resource availability may constrain the expression of adaptive maternal effects, and the specific pattern of allocation of these effects among offspring depending on their sex or birth order can result in different fitness payoffs to parents. Declining egg mass with laying order observed in several bird species may constitute an adaptive strategy of parental favouritism towards early hatching offspring with larger reproductive value but may also result from nutritional constraints on laying effort. A previous study has shown that the small size of the third, last laid (c-)egg in yellow-legged gull (Larus michahellis) clutches depends on food availability and that food-supplemented mothers increase the size of their female but not male c-eggs. Here, we show that increased mass of c-eggs laid by females supplemented with food after clutch initiation depends on increased albumen mass, which, in turn, enhances the size of daughters at hatching. Because asynchronous hatching results in a competitive disadvantage of c-chicks, present results suggest that mothers relieved from nutritional constraints enhance the size of daughters to compensate for their larger susceptibility to hatching last. The study also confirms the role of egg albumen content in determining hatchling size, previously experimentally detected only in one species in the wild. The effect of increased egg mass on offspring size persisted at least until day 8 after hatching, when, however, it did not vary with sex, suggesting intense negative selection on small female c-chicks in control broods. Hence, maternal effects mediated by egg albumen content had persistent effects on offspring size. 相似文献
420.
Analytical methods applicable to different organic wastes are needed to establish the extent to which readily biodegradable organic matter has decomposed (i.e., biological stability). The objective of this study was to test a new respirometric method for biological stability determination of organic wastes. Dynamic respiration index (DRI) measurements were performed on 16 organic wastes of different origin, composition, and biological stability degree to validate the test method and result expression, and to propose biological stability limits. In addition, theoretical DRI trends were obtained by using a mathematical model. Each test lasted 96 h in a 148-L-capacity respirometer apparatus, and DRI was monitored every hour. The biological stability was expressed as both single and cumulative DRI values. Results obtained indicated that DRI described biological stability in relation to waste typology and age well, revealing lower-stability waste characterized by a well-pronounced DRI profile (a marked peak was evident) that became practically flat for samples with higher biological stability. Fitting indices showed good model prediction compared with the experimental data, indicating that the method was able to reproduce the aerobic process, providing a reliable indication of the biological stability. The DRI can therefore be proposed as a useful method to measure the biological stability of organic wastes, and DRI values, calculated as a mean of 24 h of the highest microbial activity, of 1000 and 500 mg O(2) kg(-1) volatile solids (VS) h(-1) are proposed to indicate medium (e.g., fresh compost) and high (e.g., mature compost) biological stabilities, respectively. 相似文献