全文获取类型
收费全文 | 1101篇 |
免费 | 12篇 |
国内免费 | 20篇 |
专业分类
安全科学 | 24篇 |
废物处理 | 68篇 |
环保管理 | 116篇 |
综合类 | 131篇 |
基础理论 | 271篇 |
环境理论 | 4篇 |
污染及防治 | 357篇 |
评价与监测 | 91篇 |
社会与环境 | 62篇 |
灾害及防治 | 9篇 |
出版年
2023年 | 17篇 |
2022年 | 47篇 |
2021年 | 47篇 |
2020年 | 22篇 |
2019年 | 21篇 |
2018年 | 44篇 |
2017年 | 53篇 |
2016年 | 54篇 |
2015年 | 32篇 |
2014年 | 77篇 |
2013年 | 102篇 |
2012年 | 59篇 |
2011年 | 90篇 |
2010年 | 69篇 |
2009年 | 50篇 |
2008年 | 55篇 |
2007年 | 64篇 |
2006年 | 48篇 |
2005年 | 27篇 |
2004年 | 26篇 |
2003年 | 30篇 |
2002年 | 22篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有1133条查询结果,搜索用时 225 毫秒
211.
Juan C. Alonso Marina Magaña Carlos Palacín Carlos A. Martín 《Behavioral ecology and sociobiology》2010,64(10):1589-1600
We examined how mating success varied in relation to age, weight, body size, and display behavior among great bustard Otis tarda males. The estimated mating success was strongly skewed, with 45% of adult males being involved in copulation attempts and
only 9.7% actually seen copulating successfully. Unlike most birds, body size continued increasing in great bustards several
years after reaching sexual maturity. Age, weight, and display effort were all significant and independent predictors of male
mating success. The higher display effort involved performing longer full-display bouts. Older males could detach from the
male flock earlier in the season as well as on each day and spend longer seasonal and daily periods displaying as solitary
birds, which contributed to increase their mating success. In contrast, males weighing more did not invest more in display,
which suggests that they could be recognized as dominants by other males and selected by females through assessment of their
plumage sexual traits. In contrast to most other bird species, the system described for great bustards resembles that found
in some lek-mating ungulates, where social rank is a complex trait determined by both age and mass, and as in these mammals,
it suggests that sexual selection continues to favor a high male weight in this extremely sexually dimorphic species. 相似文献
212.
We examine the control of air pollution caused by households burning wood for heating and cooking in the developing world. Since the problem is one of controlling emissions from nonpoint sources, regulations are likely to be directed at household choices of wood consumption and combustion technologies. Moreover, these choices are subtractions from, or contributions to, the pure public good of air quality. Consequently, the efficient policy design is not independent of the distribution of household income. Since it is unrealistic to assume that environmental authorities can make lump sum income transfers part of control policies, efficient control of air pollution caused by wood consumption entails a higher tax on wood consumption and a higher subsidy for more efficient combustion technologies for higher income households. Among other difficulties, implementing a policy to promote the adoption of cleaner combustion technologies must overcome the seemingly paradoxical result that efficient control calls for higher technology subsidies for higher income households. 相似文献
213.
García-Llorente M Martín-López B Nunes PA González JA Alcorlo P Montes C 《Environmental management》2011,48(3):418-435
Biological invasions occur worldwide, and have been the object of ecological and socio-economic research for decades. However, the manner in which different stakeholder groups identify the problems associated with invasive species and confront invasive species management under different policies remains poorly understood. In this study, we conducted an econometric analysis of the social factors influencing willingness to pay for invasive alien species management under two different regimes: eradication and prevention in the Doñana Natural Protected Area (SW Spain). Controlling for the participation of local residents, tourists and conservationists, email and face-to-face questionnaires were conducted. Results indicated that respondents were more willing to pay for eradication than prevention; and public support for invasive alien species management was influenced by an individual’s knowledge and perception of invasive alien species, active interest in nature, and socio-demographic attributes. We concluded that invasive alien species management research should confront the challenges to engage stakeholders and accept any tradeoffs necessary to modify different conservation policies to ensure effective management is implemented. Finally, our willingness to pay estimates suggest the Department of Environment of Andalusian Government has suitable social support to meet the budgetary expenditures required for invasive alien species plans and adequate resources to justify an increase in the invasive alien species management budget. 相似文献
214.
Rita JC Gama-Rodrigues EF Gama-Rodrigues AC Polidoro JC Machado RC Baligar VC 《Environmental management》2011,48(1):134-141
Agroforestry systems (AFSs) have an important role in capturing above and below ground soil carbon and play a dominant role
in mitigation of atmospheric CO2. Attempts has been made here to identify soil organic matter fractions in the cacao-AFSs that have different susceptibility
to microbial decomposition and further represent the basis of understanding soil C dynamics. The objective of this study was
to characterize the organic matter density fractions and soil size fractions in soils of two types of cacao agroforestry systems
and to compare with an adjacent natural forest in Bahia, Brazil. The land-use systems studied were: (1) a 30-year-old stand
of natural forest with cacao (cacao cabruca), (2) a 30-year-old stand of cacao with Erythrina glauca as shade trees (cacao + erythrina), and (3) an adjacent natural forest without cacao. Soil samples were collected from 0-10 cm
depth layer in reddish-yellow Oxisols. Soil samples was separated by wet sieving into five fraction-size classes (>2000 μm,
1000–2000 μm, 250–1000 μm, 53–250 μm, and <53 μm). C and N accumulated in to the light (free- and intra-aggregate density
fractions) and heavy fractions of whole soil and soil size fraction were determined. Soil size fraction obtained in cacao
AFS soils consisted mainly (65 %) of mega-aggregates (>2000 μm) mixed with macroaggregates (32–34%), and microaggregates (1–1.3%).
Soil organic carbon (SOC) and total N content increased with increasing soil size fraction in all land-use systems. Organic
C-to-total N ratio was higher in the macroaggregate than in the microaggregate. In general, in natural forest and cacao cabruca
the contribution of C and N in the light and heavy fractions was similar. However, in cacao + erythrina the heavy fraction
was the most common and contributed 67% of C and 63% of N. Finding of this study shows that the majority of C and N in all
three systems studied are found in macroaggregates, particularly in the 250–1000 μm size aggregate class. The heavy fraction
was the most common organic matter fraction in these soils. Thus, in mature cacao AFS on highly weathered soils the main mechanisms
of C stabilization could be the physical protection within macroaggregate structures thereby minimizing the impact of conversion
of forest to cacao AFS. 相似文献
215.
Food and drink waste is a significant problem for economic, environmental and food security reasons. Government efforts have focused on diverting waste away from landfill through regulation, taxation and public awareness. However, efforts to understand why waste occurs have been limited, particularly in the interface between retailers and suppliers. This research aims to address this problem by identifying the main root causes of waste in the supplier-retailer interface.The research is exploratory in nature as there is a paucity of studies focusing on food waste across the supply chain. Data were collected through 43 interviews with managers in food manufacturing, wholesaling and retailing in two countries: the UK (24) and Spain (19). Data from the interviews and supplementary documentation were analyzed using causal maps. This approach helped to identify the main root causes of waste which were categorized into three groups: (1) mega-trends in the marketplace, (2) natural causes related to the products and processes, and (3) management root causes on which practitioners have a direct impact.The paper discusses the root causes of food waste and good practices identified from the interviews. Differences between the UK and Spain are discussed, presenting potential learning opportunities for practitioners in these countries and highlighting opportunities for further research. 相似文献
216.
Age effect on the antioxidant activity of Daphnia magna (Anomopoda: Daphniidae): does younger mean more sensitivity? 总被引:1,自引:0,他引:1
Alberto AC Rocío OB Fernando MJ 《Journal of environmental biology / Academy of Environmental Biology, India》2011,32(4):481-487
It has been accepted that for most species newborns and senescent organisms are more sensitive than other ages to environmental stressors. Nevertheless, it must be considered that there are several biochemical and physiological compensatory processes which are not expressed with the same magnitude during the whole life cycle. With this aim, Daphnia magna individuals of different age were exposed to hexavalent chromium, Cr (VI), at two different sublethal concentrations (0.032 and 0.0064 mg l(-1)), and the activity of some antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and glutathione peroxidase (GPx) were evaluated during most of the life cycle of this cladoceran. The antioxidant enzymatic activity showed an inverse relationship with respect to age. The activity of CAT, GR and GPx were increased in the two treated groups, at all life stages tested. On the other hand, the activity of SOD decreased in the same groups. Both, increase and decrease in the antioxidant enzymatic activities, showed significant differences with respect to the control group, being higher for the 0.032 mg l(-1) group. The Cr (VI) LC50 was also estimated for these age groups, finding statistical differences among them. Even though adults exhibited higher responses, these enzymatic activity changes should not be interpreted as higher sensitivity, since the daphnids acute chromium toxicity followed a different pattern, with increasing LC50 values according to age. 相似文献
217.
Judith Morales Alberto Velando Roxana Torres 《Behavioral ecology and sociobiology》2011,65(2):197-203
Avian eggshell color is remarkably variable among and within species and its possible function has long been controversial.
Female birds use biliverdin pigment to color their eggs blue and green. Although evidence is accumulating that blue-green
eggshell coloration is costly to produce, the exact mechanisms underlying its expression are little studied. Biliverdin pigment
is involved in important maintenance functions such as immune and antioxidant defenses and shows similar properties to carotenoid
pigments. Carotenoids play a role as immunoenhancers and have the potential to ameliorate the impact of oxidative processes,
although their antioxidant function could be minor for some bird species. Important life-history components can be limited
by carotenoid availability, including sexual displays and fecundity. Here we explored if biliverdin-based eggshell pigmentation
was affected by carotenoid availability in a seabird, by performing a carotenoid supplementation experiment in female blue-footed
boobies (Sula nebouxii) after laying their first egg. In this species, blue eggshell color is associated with incubation patterns, and carotenoid
availability affects the crucial trade-off between female foot ornamentation and fecundity. We found that under natural conditions,
there was a decline in eggshell color with laying order, suggesting pigment limitation for females. However, carotenoid-supplemented
females had enhanced second egg coloration compared to controls, and the color increase was independent of their previous
pigment allocation to the first egg. Our results suggest that biliverdin-based eggshell coloration is costly to produce and
can be alleviated by current carotenoid availability. 相似文献
218.
Gloria Massamba-N’Siala Roberto Simonini Piero Cossu Ferruccio Maltagliati Alberto Castelli Daniela Prevedelli 《Marine Biology》2011,158(7):1523-1535
The spatial scale of life-history and demographic variation was investigated in the opportunistic polychaete Ophryotrocha labronica La Greca and Bacci. Individuals were collected along the Italian coasts from three thermally different biogeographical regions
of the Mediterranean Sea. For each region, populations from four harbours were considered, and for each harbour, two sites
were examined. Life-history and demographic traits were investigated after one generation under a common garden experiment,
and their variation at the three spatial scales was assessed. All the traits showed high variability with regard to site.
A number of life-history and all demographic traits also varied according to the biogeographical region. Conversely, no differences
were found between harbours, suggesting that geographical isolation did not contribute to phenotypic variation. Results confirmed
the central role of local conditions for the evolution of life history in species colonizing heterogeneous environments, but
they also pointed to the importance of large-scale factors in shaping the phenotypic responses of O. labronica, demonstrating the need for a multi-scale approach for obtaining a good measure of natural variation in widespread opportunistic
species. 相似文献
219.
Flávia Noronha Dutra Ribeiro Jacyra Soares Amauri Pereira de Oliveira 《Environmental Fluid Mechanics》2011,11(6):551-572
This work investigates the capability of an oceanic numerical model dynamic and thermodynamically coupled to a three-dimensional
mesoscale atmospheric numerical model to simulate the basic features of the air–sea interaction in the coastal upwelling area
of Cabo Frio (RJ, Brazil). The upwelling/downwelling regime is an important feature in the oceanic circulation of Cabo Frio
and determines the sustainability of local ecosystems. This regime is predominantly driven by the atmospheric circulation
and is well documented, being suitable to be used as test reference for atmospheric and oceanic coupled and uncoupled models.
The oceanic boundary conditions, coastline shape and coupling effect have been tested. The uncoupled oceanic model forced
by a NE (SW) wind field generates a realistic upwelling (downwelling) phenomenon regardless of the proximity of the lateral
boundary and how realistic is the shape of the coastline. The atmospheric-oceanic coupled model generates an upwelling location
and intensity similar to the uncoupled simulation, but the upwelling is gradually enhanced by the sea-breeze circulation.
It also generates vertical profiles of mixing ratio that compare better to the observations than the uncoupled simulation
and air potential temperature and wind vertical profiles that represent particular features of the atmospheric circulation
at Cabo Frio. 相似文献
220.
This study quantifies metal concentrations in washed and unwashed feathers of feral pigeons (Columba livia). The material was collected in two different sites: Goiania (capital of Goiás State), with high anthropic activities, and Jataí (a city in Goiás), with low anthropic activities. Results revealed that metals such as Pb, Cr, and Cd were deposited in the feathers originating from air and soil (exogenous process). Other metals such as Cu, Fe, Mn, and Zn, which are part of the tissue constitution of a living being, were absorbed through the pigeons' diet (endogenous process). There was a statistically significant difference between mean values of Cd, Pb, and Cr in the three collection sites. The order of metal concentrations were Civic Square > Zoo > Jataí, which shows highest levels of metal contamination in anthropic environments. Significant differences between Cd, Pb, and Cr in washed and unwashed feathers suggest that metal concentrations are directly related to exposure time due to exogenous sources. We concluded that it is possible to quantify and monitor metal levels in the environment by analyzing the feathers of urban feral pigeons. Furthermore, unwashed feathers were especially efficient to investigate endogenous and exogenous absorption of the metals in our study. 相似文献