全文获取类型
收费全文 | 467篇 |
免费 | 12篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 21篇 |
废物处理 | 14篇 |
环保管理 | 83篇 |
综合类 | 38篇 |
基础理论 | 122篇 |
污染及防治 | 122篇 |
评价与监测 | 37篇 |
社会与环境 | 37篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 22篇 |
2015年 | 18篇 |
2014年 | 9篇 |
2013年 | 37篇 |
2012年 | 14篇 |
2011年 | 29篇 |
2010年 | 18篇 |
2009年 | 22篇 |
2008年 | 23篇 |
2007年 | 23篇 |
2006年 | 18篇 |
2005年 | 29篇 |
2004年 | 20篇 |
2003年 | 19篇 |
2002年 | 15篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1977年 | 6篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1971年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有481条查询结果,搜索用时 312 毫秒
171.
Island Extinction Rates from Regular Censuses 总被引:1,自引:0,他引:1
Regular censuses conducted over a long time allow the calculation of both extinction and immigration rates. We present formulae for estimation of those rates. We use them on bird censuses of three British islands. These formulae improve on previous estimators of extinction but reaffirm that smaller populations have a higher probability of becoming extinct. On the other hand, they suggest no correlation between extinction rate and either body size or migratory status among birds. 相似文献
172.
173.
Colin A. Chapman 《Behavioral ecology and sociobiology》1990,26(6):409-414
Summary In this paper I consider how the costs and benefits of group living in spider monkeys (Ateles geoffroyi) vary between troop members. The results suggest that ecological factors set an upper limit to the number of spider monkeys that can associate and still efficiently exploit the available resources. In addition, the needs of the individual appears to influence the type and size of the subgroup it chooses. Adult males band together, travel over a large area, and are frequently sighted near the community's boundary. In contrast, adult females spend more time solitary than males and have association patterns that are strongly influenced by the presence of a dependent infant. Females with dependent infants tend to travel in small subgroups or alone, avoid the boundaries of the community's home range, and exhibit a restricted pattern of use of their range. The results suggest that males may be attempting to locate females with which they can breed, while mothers attempt to protect their infants by avoiding conspecifics and potentially dangerous situations near territorial boundaries. 相似文献
174.
Fungal activity is thought to play a direct and effective role in the breakdown and dissolution of primary minerals and in the synthesis of clay minerals in soil environments, with important consequences for plant growth and ecosystem functioning. We have studied primary mineral weathering in volcanic soils developed on trachydacite in southern Tuscany using a combination of qualitative and quantitative mineralogical and microbiological techniques. Specifically, we characterized the weathering and microbiological colonization of the magnetically separated ferromagnesian minerals (biotite and orthopyroxene) and non-ferromagnesian constituents (K-feldspar and volcanic glass) of the coarse sand fraction (250-1,000 microm). Our results show that in the basal horizons of the soils, the ferromagnesian minerals are much more intensively colonized by microorganisms than K-feldspar and glass, but that the composition of the microbial communities living on the two mineral fractions is similar. Moreover, X-ray diffraction, optical and scanning electron microscope observations show that although the ferromagnesian minerals are preferentially associated with an embryonic form of the clay mineral halloysite, they are still relatively fresh. We interpret our results as indicating that in this instance microbial activity, and particularly fungal activity, has not been an effective agent of mineral weathering, that the association with clay minerals is indirect, and that fungal weathering of primary minerals may not be as important a source of plant nutrients as previously claimed. 相似文献
175.
176.
Jim W. Hall Edward P. Evans Edmund C. Penning-Rowsell Paul B. Sayers Colin R. Thorne Adrian J. Saul 《Environmental Hazards》2013,12(2):51-65
Flood risk to the economy, society and the environment reflects the cumulative effects of environmental and socio-economic change over decades. Long-term scenarios are therefore required in order to develop robust and sustainable flood risk management policies. Quantified national-scale flood risk analysis and expert appraisal of the mechanisms causing change in flood risk have been used to assess flood risk in England and Wales over the period 2030–2100. The assessment involved the use of socio-economic and climate change scenarios. The analysis predicts increasing flood risk unless current flood management policies, practices and investment levels are changed—up to 20-fold increase in economic risk by the 2080s in the scenario with highest economic growth. The increase is attributable to a combination of climate change (in particular increasing precipitation and relative sea level rise in parts of the UK) and increasing socio-economic vulnerability, particularly in terms of household/industrial contents and infrastructure vulnerability. The policy implications of these findings are discussed. 相似文献
177.
Magneto-biomonitoring of intra-urban spatial variations of particulate matter using tree leaves 总被引:1,自引:0,他引:1
Preliminary mineral magnetic results from a pilot project investigating the suitability of roadside tree leaves as depositories
of vehicular pollution are presented. Tree leaf surfaces (Lime: Tilia europaea; Sycamore: Acer pseudoplatanus) at four roadside and one woodland location in Wolverhampton, UK, have been monitored (July 2003 to November 2003). Mineral
magnetic technologies have revealed spatial variations of particulate pollution concentration throughout the conurbation and
data analysis indicates that magnetic concentration parameters are suitable proxies for fine particulate pollution, which
are particularly hazardous to health. Site-specific traffic management and associated vehicle behaviour appear to be chiefly
responsible for the magnetic concentration differences between sites. Magneto-biomonitoring in this way allows the high-resolution
spatial mapping of particulate matter (PM) pollution, which may also benefit epidemiology in better assessing exposure to
vehicular-derived particulates. Given the speed, measurement sensitivity and non-destructive nature of the technique, it is
proposed that this low-cost approach offers some advantages over centralised monitoring stations to monitor urban roadside
particulate pollution. 相似文献
178.
Ecologists trying to understand the value of habitat to animals must first describe the value of resources contained in the habitat to animals and, second, they must describe spatial variation in resource quality at a resolution relevant to individual animal foraging. We addressed these issues in a study of koalas (Phascolarctos cinereus) in a Eucalyptus woodland. We measured beneficial and deterrent chemical characteristics as well as the palatability of trees using a near-infrared spectroscopic model based on direct feeding experiments. Tree use by koalas was influenced by tree size and foliar quality but was also context-dependent: trees were more likely to be visited if they were surrounded by small, unpalatable trees or by large, palatable trees. Spatial autocorrelation analysis and several mapping approaches demonstrated that foliar quality is spatially structured in the woodland at a scale relevant to foraging decisions by koalas and that the spatial structure is an important component of habitat quality. 相似文献
179.
Alain Houle Colin A. Chapman William L. Vickery 《Behavioral ecology and sociobiology》2010,64(3):429-441
Recently, we demonstrated that the highest densities of fruit pulp are located in the uppermost zones of tree crowns. Since
heterogeneous distributions of depletable food is theorized to foster contest competition, we tested three hypotheses involving
rank differences among species of arboreal frugivores: (1) In the absence of competitors, species tend to feed in higher strata
of tree crowns; (2) interspecific contest competition occurs through monopolization and usurpation of feeding sites in these
higher strata; and (3) subordinate species decrease their feeding height and ingestion rate when dominants enter the food
patch. To test these hypotheses, we observed chimpanzees (Pan troglodytes), red-tailed monkeys (Cercopithecus ascanius), blue monkeys (Cercopithecus mitis), and gray-cheeked mangabeys (Lophocebus albigena) in Kibale National Park, Uganda. We found that: (1) all four primates fed preferentially in upper tree crowns when alone,
(2) dominant species monopolized and aggressively usurped the upper crown when co-feeding with subordinates and the latter
retreated below the middle of tree crowns, (3) in the presence of dominant species, subordinate species showed lower standardized
feeding height and modified their food intake rates, while dominants were not affected by the subordinate species, (4) subordinates
moved down at the arrival of and up at the departure of dominants, and (5) the presence of folivores in the tree did not affect
the feeding height of a frugivore, even through folivores were socially dominant. Contrary to expectations, we found that
red-tailed monkeys decreased their movements between successive fruits that they ate in the presence of blue monkeys compared
to when they were feeding alone, perhaps to avoid disturbing dominants and attracting aggression or because they ingested
more semi-ripe and green unripe fruits, i.e., more food of lower quality. 相似文献
180.
Because choice is conflict, decision-making is necessarily about conflict resolution. Choices are necessary because the options
are mutually exclusive but the nature of this inherent conflict varies. Typically, these conflicts are multidimensional. In
coasal zones, the complex interactions between systems makes decision-making particularly complex; in particular, environmental
interests are themselves frequently in conflict. In making a choice, it is important to determine why that choice is necessary
in the first place.
There are further conflicts about the objectives to be satisfied by the decision process; between the determination of the
best outcome and the best decision process. Social scientists centre upon the requirement for a fair decision process rather
than upon seeking an optimum outcome. Unlike physical scientists who seek more and better information, social scientists focus
upon the development and maintenance of institutions. 相似文献