全文获取类型
收费全文 | 663篇 |
免费 | 17篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 29篇 |
废物处理 | 31篇 |
环保管理 | 103篇 |
综合类 | 94篇 |
基础理论 | 168篇 |
环境理论 | 1篇 |
污染及防治 | 151篇 |
评价与监测 | 45篇 |
社会与环境 | 48篇 |
灾害及防治 | 17篇 |
出版年
2023年 | 12篇 |
2022年 | 9篇 |
2021年 | 15篇 |
2020年 | 22篇 |
2019年 | 11篇 |
2018年 | 33篇 |
2017年 | 18篇 |
2016年 | 25篇 |
2015年 | 23篇 |
2014年 | 13篇 |
2013年 | 53篇 |
2012年 | 29篇 |
2011年 | 40篇 |
2010年 | 28篇 |
2009年 | 33篇 |
2008年 | 23篇 |
2007年 | 30篇 |
2006年 | 24篇 |
2005年 | 24篇 |
2004年 | 13篇 |
2003年 | 21篇 |
2002年 | 28篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 10篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1972年 | 2篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1931年 | 2篇 |
排序方式: 共有687条查询结果,搜索用时 15 毫秒
661.
Alexander D. M. Wilson Stefan Krause Niels J. Dingemanse Jens Krause 《Behavioral ecology and sociobiology》2013,67(1):163-173
In recent years, animal social interactions have received much attention in terms of personality research (e.g. aggressive or cooperative interactions). However, other components of social behaviour such as those describing the intensity, frequency, directedness and individual repeatability of interactions in animal groups have largely been neglected. Network analysis offers a valuable opportunity to characterize individual consistency of traits in labile social groups and therein provide novel insights to personality research in ways previously not possible using traditional techniques. Should individual network positions be consistently different between individuals under changing conditions, they might reflect expressions of an individual's personality. Here, we discuss a conceptual framework for using network analyses to infer the presence of individual differences and present a statistical test based on randomization techniques for testing the consistency of network positions in individuals. The statistical tools presented are useful because if particular individuals consistently occupy key positions in social networks, then this is also likely to have consequences for their fitness as well as for that of others in the population. These consequences may be particularly significant since individual network position has been shown to be important for the transmission of diseases, socially learnt information and genetic material between individuals and populations. 相似文献
662.
Walter Leal Filho Merit Mandel Abul Quasem Al-Amin Alexander Feher Charbel José Chiappetta Jabbour 《国际发展与全球生态学杂志》2013,20(6):554-560
ABSTRACTThe agriculture sector is the principal source of income for around 20% of the EU-26 population, which live in predominantly rural regions that would be devastated without its contribution. Moreover, the combined agricultural and food sector forms an important part of the EU economy, accounting for 15 million jobs (8.3% of total employment) and 4.4% of GDP. The 12 million active farmers across Europe today, have an average farm size of about 15 ha, and are expected to meet the needs of 500 million Europeans. In addition, they are also expected to promote a sustainable and balanced development of their land, also in areas where production conditions are difficult. Yet, despite the relevance of the sector, the use of land for agriculture purposes is not very sustainable. Among other issues, there is a serious problem in respect of the abandonment of agricultural land. Based on the perceived need for research on this topic, the aim of this paper is to examine the causes and consequences of agricultural land abandonment, outlining its social, economic and environmental impacts, as well as the implications for territorial integration. 相似文献
663.
Franck Quero Stephen J. Eichhorn Masaya Nogi Hiroyuki Yano Koon-Yang Lee Alexander Bismarck 《Journal of Polymers and the Environment》2012,20(4):916-925
This article presents approaches to maximize the mechanical performance of bacterial cellulose/poly(lactic acid) composites through chemical modification of the interface. This is achieved by both cross-linking the layered bacterial cellulose structure and by grafting maleic anhydride to the matrix material. Unmodified and glyoxalized bacterial cellulose (BC) networks have been embedded in poly(lactic acid) (PLA) resin and then in maleated resin using a compression molding method. The effect of these chemical modifications on the physical properties of these composites is reported. The tensile properties of the composites showed that Young??s moduli can be increased significantly when both BC networks and PLA were chemically modified. Interface consolidation between layers in BC networks has been achieved by glyoxalization. The effect of these modifications on both stress-transfer between the fibers and between the matrix and the fibers was quantified using Raman spectroscopy. Two competitive deformation mechanisms are identified; namely the mobility between BC layers, and between BC and PLA. The coupling strength of these interfaces could play a key role for optimization of these composites?? mechanical properties. 相似文献
664.
A simulation model was developed to investigate the relative effects of temperature, oxygen concentration, substrate content and competition by autochthonous microbial community on the oscillatory behaviour and survival of Escherichia coli O157:H7 in manure and manure-amended soil. The overall decline in E. coli O157:H7 was primarily determined by competition with autochthonous copiotrophic bacteria simulated by an inter-specific competition term according to Lotka-Volterra. Oscillations of bacterial populations were attained by the relationships between relative growth and death rates with readily available substrate content. The model contains a logistic and exponential relation of relative growth and death rates, respectively, of E. coli O157:H7 and copiotrophic bacteria with temperature, resulting in optimum curves for net growth rates similar to the curves reported in the literature. The model has been both calibrated and validated on experimental data. The model was used to perform sensitivity analysis and to evaluate different manure and soil management scenarios in terms of survival of E. coli O157:H7. The relative effects of changes in temperature on simulated survival time of E. coli O157:H7 were more pronounced than changes in oxygen condition. Testing manure storage scenarios with realistic data revealed that manure stored in a heap that was turned every week resulted in almost 70% reduction of E. coli O157:H7 survival compared to unturned manure. At the surface of a heap with unturned manure, simulated survival time was the longest (2.4 times longer than inside the same heap). The simulation model provides a new approach to investigating dynamic changes of invasive microorganisms in natural substrates such as manure or manure-amended soil. 相似文献
665.
The appropriate prediction of the fate of the contaminant is an essential step when evaluating the risk of severe groundwater pollutions-in particular in the context of natural attenuation. We numerically study the reactive transport of phenanthrene at the field scale in a multilayer soil profile based on experimental data. The effect of carrier facilitation by dissolved organic carbon is emphasized and incorporated in the model. Previously published simulations are restricted to the saturated zone and/or to homogeneous soil columns at the laboratory scale. A numerical flow and transport model is extended and applied to understand and quantify the relevant processes in the case of a strongly sorbing hydrophobic organic compound that is subject to carrier facilitation in the unsaturated zone. The contaminant migration is investigated on long- and short-term time scales and compared to predictions without carrier facilitation. The simulations demonstrate the importance of carrier facilitation and suggest strongly to take this aspect into account. By carrier facilitation breakthrough times at the groundwater level decreased from 500 to approximately 8 years and concentration peaks increased by two orders of magnitude in the long-term simulation assuming a temporary spill in an initially unpolluted soil with a non-sorbing carrier. 相似文献
666.
667.
Alexander D 《Disasters》2002,26(1):1-9
This paper compares the terrorist outrages of 11 September 2001 in New York City and Washington to the Lisbon earthquake of 1 November 1755. Both events occurred, literally out of the blue, at critical junctures in history and both struck at the heart of large trading networks. Both affected public attitudes towards disaster as, not only did they cause unparalleled destruction, but they also represented symbolic victories of chaos over order, and of moral catastrophism over a benign view of human endeavour. The Lisbon earthquake led to a protracted debate on teleology, which has some parallels in the debate on technological values in modern society. It remains to be seen whether there will be parallels in the reconstruction and the ways in which major disasters are rationalised in the long term. But despite the differences between these two events--which are obviously very large as nearly 250 years of history separate them and they were the work of different sorts of forces--there are lessons to be learned from the comparison. One of these is that disaster can contribute to a perilous form of self absorption and cultural isolation. 相似文献
668.
669.
670.