全文获取类型
收费全文 | 425篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 17篇 |
废物处理 | 17篇 |
环保管理 | 91篇 |
综合类 | 54篇 |
基础理论 | 115篇 |
污染及防治 | 84篇 |
评价与监测 | 37篇 |
社会与环境 | 13篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 11篇 |
2016年 | 11篇 |
2015年 | 12篇 |
2014年 | 14篇 |
2013年 | 26篇 |
2012年 | 13篇 |
2011年 | 30篇 |
2010年 | 13篇 |
2009年 | 17篇 |
2008年 | 27篇 |
2007年 | 26篇 |
2006年 | 15篇 |
2005年 | 18篇 |
2004年 | 7篇 |
2003年 | 14篇 |
2002年 | 20篇 |
2001年 | 11篇 |
2000年 | 10篇 |
1999年 | 11篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1963年 | 1篇 |
1959年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有433条查询结果,搜索用时 484 毫秒
211.
Bacon JR Farmer JG Dunn SM Graham MC Vinogradoff SI 《Environmental pollution (Barking, Essex : 1987)》2006,141(3):469-481
Sequential extraction (modified BCR procedure) combined with isotope analysis has been investigated as a tool for assessing mobilisation of lead into streams at an upland catchment in NE Scotland. The maximum lead concentrations (up to 110 mg kg(-1) in air-dried soil) occurred not at the surface but at about 10 cm depth. The lowest (206)Pb/(207)Pb ratios in any profile occurred, with one exception, at 2.5-5 cm depth. In the one exception, closest to the only road in the area, significantly lower (206)Pb/(207)Pb ratios in the surface soil together with much increased chloride concentrations (in comparison to other surface waters) indicated the possible mobilisation of roadside lead and transfer to the stream. The (206)Pb/(207)Pb ratios in extractable fractions tended at depth towards the ratio measured in the residual phase but the ratios in the oxidizable fraction increased to a value higher than that of the residual phase. 相似文献
212.
Allan IJ Semple KT Hare R Reid BJ 《Environmental pollution (Barking, Essex : 1987)》2006,144(2):562-571
In this study, an aqueous-based hydroxypropyl-beta-cyclodextrin (HPCD) extraction technique was assessed for its capacity to determine the microbially degradable fraction of mono- and polycyclic aromatic hydrocarbons in four dissimilar soils. A linear relationship (slope=0.90; R2=0.89), approaching 1:1 between predicted and observed phenanthrene mineralization, was demonstrated for the cyclodextrin extraction; however, the water only extraction underestimated the microbially available fraction by a factor of three (slope=3.35; R2=0.64). With respect to determining the mineralizable fraction of p-cresol in soils, the cyclodextrin extraction (slope=0.94; R2=0.84) was more appropriate than the water extraction (slope=1.50; R2=0.36). Collectively, these results suggested that the cyclodextrin extraction technique was suitable for the prediction of the mineralizable fraction of representative PAHs and phenols present in dissimilar soils following increasing soil-contaminant contact times. The assessment of the microbial availability of contaminants in soils is important for a more representative evaluation of soil contamination. 相似文献
213.
214.
Among group-living organisms, some individuals initiate groups by being the first to attack a prey item or the first to colonize a new settlement site. In the group-living mountain pine beetle (Dendroctonus ponderosae), first attackers (known as pioneers) on live trees suffer higher mortality due to tree defenses than do beetles that join aggregations. This study examined factors that affect an individual’s propensity to initiate an aggregation. When placed on an unoccupied tree, the probability of successfully entering the tree was positively correlated with body condition (residual of mass versus length regression). However, beetles in better condition took longer to initiate tunnel construction than those in poorer condition, suggesting that pioneering is a “desperation” strategy used when low energy reserves preclude further dispersal or when potential trees are rare. These contrasting patterns suggest pioneering is a nonlinear behavioral response, such that beetles with the smallest energy reserves and beetles with the greatest energy reserves both avoid pioneering. We further found that pioneering was more likely when the environment favored success, such as in smaller diameter trees (which may have weaker defenses) and earlier in the season (when the probability of recruiting conspecifics is higher). Our results suggest that pioneers incorporate both internal and external variables in their decision to attack an uncolonized tree. 相似文献
215.
Sigal Balshine Brenda Leach Francis Neat Hannah Reid Michael Taborsky Noam Werner 《Behavioral ecology and sociobiology》2001,50(2):134-140
Neolamprologus pulcher, a cooperatively breeding cichlid fish from Lake Tanganyika, lives in permanent social groups comprising one breeding pair and helpers of both sexes. Variation in group size (1-14 helpers) provides an opportunity to investigate factors that affect how many helpers remain in a group and in turn how group size affects reproductive success. This field study showed that larger groups live in larger territories with more shelter. Group size was more strongly correlated with territory quality than with breeder size. Experimental enhancement of territory quality did not affect group size but group size decreased when territory quality was reduced. Breeders living in a large group benefit because such individuals feed more often and have lower workloads and greater reproductive success. Helpers in larger groups also fed more frequently but did not have lower workloads. This is one of the first experimental studies to examine the factors influencing group size in cooperative breeders. 相似文献
216.
217.
Robin S. Reid Philip K. Thornton Graeme J. McCrabb Russell L. Kruska Fred Atieno Peter G. Jones 《Environment, Development and Sustainability》2004,6(1-2):91-109
Climate change science has been discussed and synthesized by the world's best minds at unprecedented scales. Now that the Kyoto Protocol may become a reality, it is time to be realistic about the likelihood of success of mitigation activities. Pastoral lands in the tropics hold tremendous sequestration potential but also strong challenges to potential mitigation efforts. Here we present new analyses of the global distribution of pastoral systems in the tropics and the changes they will likely undergo in the next 50 years. We then briefly summarize current mitigation options for these lands. We then conclude by attempting a pragmatic look at the realities of mitigation. Mitigation activities have the greatest chance of success if they build on traditional pastoral institutions and knowledge (excellent communication, strong understanding of ecosystem goods and services) and provide pastoral people with food security benefits at the same time. 相似文献
218.
Nick J. Royle Margaret E. Hall Jonathan D. Blount Scott Forbes 《Behavioral ecology and sociobiology》2011,65(2):313-323
Despite their importance to offspring fitness outcomes, there has been little previous work on egg-mediated maternal effects
in avian brood parasites which lay their eggs in the nests of other species. Here, we examine patterns of egg yolk antioxidant
deposition in an avian host (red-winged blackbird, Agelaius phoeniceus) and their brood parasite (brown-headed cowbird, Molothrus ater). Cowbird nestlings compete directly for food with host blackbird chicks and succeed, despite hatching from a smaller egg,
by begging more intensely and growing as or more rapidly than their hosts. Dietary-derived antioxidants, such as carotenoids
and vitamins E and A, deposited in egg yolk, may enhance growth rate and reduce oxidative stress, and therefore provide a
potential mechanism by which female cowbirds could enhance the competitiveness of their young in host nests. However, provision
of antioxidants to eggs is costly so we predicted that female cowbirds should adjust the amount of antioxidants in response
to variation in host quality. We found that whilst red-winged blackbird clutches parasitised by cowbirds did not differ in
the pattern of antioxidant deposition compared to non-parasitised clutches, levels of vitamin E deposited in cowbird eggs
were closely matched to that of the individual host clutch in which cowbirds laid their egg. This supports the prediction
that female cowbirds adjust the antioxidant concentration of their eggs to increase the likely competitiveness of their offspring
in the host nest into which they are laid and may help explain the success of cowbirds in competing with larger host young. 相似文献
219.
220.
Troy Goodnough Arne Kildegaard Margaret Kuchenreuther Lowell Rasmussen Pete Wyckoff 《Journal of Cleaner Production》2009,17(12):1138-1142
This article presents an overview of the sustainability initiative at the University of Minnesota, Morris, key components of which include a realistic goal of energy self-sufficiency by 2010, a new environmental studies curriculum, and various research and outreach projects. Many non-obvious institutional assets – such as lobbying networks in the state legislature, and geographic/demographic features that are more commonly thought of as liabilities – turned out to play critical roles in setting the initiative in motion. The initial physical assets have been leveraged into complementary opportunities for research, teaching, and institutional development in this direction. 相似文献