全文获取类型
收费全文 | 340篇 |
免费 | 15篇 |
国内免费 | 26篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 6篇 |
环保管理 | 100篇 |
综合类 | 56篇 |
基础理论 | 154篇 |
环境理论 | 1篇 |
污染及防治 | 42篇 |
评价与监测 | 10篇 |
社会与环境 | 8篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 29篇 |
2012年 | 10篇 |
2011年 | 21篇 |
2010年 | 14篇 |
2009年 | 30篇 |
2008年 | 28篇 |
2007年 | 26篇 |
2006年 | 22篇 |
2005年 | 14篇 |
2004年 | 9篇 |
2003年 | 15篇 |
2002年 | 10篇 |
2001年 | 10篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有381条查询结果,搜索用时 15 毫秒
351.
Varenka Lorenzi Ryan L. Earley Matthew S. Grober 《Behavioral ecology and sociobiology》2006,59(6):715-722
Sex change in marine teleost fishes is commonly regulated by social factors. In species that exhibit protogynous sex change,
such as the bluebanded goby Lythrypnus dalli, the most dominant female typically initiates sex change when a male is removed from the social group. Females can use visual,
chemical or tactile cues to assess the presence or absence of a male. The primary goal of our study was to determine whether
the olfactory and visual presence of a male versus its behavioural interactions with females were important for mediating
sex change. We exposed females to three different treatments: absence of a male, presence of a male that could physically
interact with her and presence of a male behind a barrier that allowed visual and olfactory interactions but prohibited physical
interactions. Sex change occurred in the absence of a male but not in the presence of a male that could physically interact
with the female. The presence of a male behind the barrier did not prevent sex change but affected the timing of sex change.
Season appeared to affect the latency to initiate male typical courtship, with a delay at the end of the reproductive season
only when the male was present behind the barrier. We discuss the seasonal results in terms of L. dalli life history and the potential benefits and costs of changing sex late in the season in the presence or absence of aggressive
reinforcement by the male. Our results identify direct behavioural interactions as an important proximate mechanism in the
social regulation of sex change in L. dalli. 相似文献
352.
Intra-specific interactions influence egg composition in the lesser black-backed gull (Larus fuscus)
Nanette Verboven Neil P. Evans Liliana D’Alba Ruedi G. Nager Jonathan D. Blount Peter F. Surai Pat Monaghan 《Behavioral ecology and sociobiology》2005,57(4):357-365
Egg composition, which is under maternal control, can have a profound effect on offspring fitness. The presence of maternal testosterone and carotenoids in avian egg yolk, for example, is thought to enhance the development and competitive ability of the offspring and protect the hatching and growing chick against oxidative stress. Egg quality often differs between females and such variation can be due to differences in maternal social environment, e.g. breeding density. However, this is confounded by the possibility that the quality of individuals breeding in high- or low-density areas may vary. We tested if maternal social environment influences egg composition in a colonial seabird, the lesser black-backed gull (Larus fuscus). To control for confounding effects of female quality, we experimentally manipulated maternal social environment during egg formation. We increased the frequency of intra-specific interactions (i.e. aggressive encounters with conspecifics other than nest mates) in which the females were involved, by placing an elevated platform in their territory. Females that took part in more intra-specific interactions produced a heavier last egg, but the yolk testosterone concentration in eggs laid by control and experimental females did not differ. Differences in yolk testosterone concentration in relation to embryo sex were found neither in the control nor in the experimental group. In contrast, within the control group, eggs with a male embryo contained more carotenoids than eggs with a female embryo. Moreover, experimental females that had been involved in more intra-specific interactions produced female eggs with higher carotenoid levels compared to female eggs of control birds. An experimental increase in carotenoid levels was not observed in eggs containing a male embryo. Our results suggest that intra-specific interactions experienced by female birds during egg formation can influence conditions for embryonic development.Communicated by J. Graves 相似文献
353.
Summary. Following herbivory, induced responses involving plant secondary metabolites have been reported in a number of tree species.
Although a wide range of plant secondary metabolites appear to operate as constitutive plant defences in trees belonging to
the Eucalyptus genus, no induced responses have as yet been reported following foliar-chewing insect damage. We empirically tested whether
branch defoliation (artificial and larval) of 2-year-old Eucalyptus globulus Labill. trees altered the abundance of specific plant secondary metabolites immediately (3 months after initial larval feeding)
and 8 months after the cessation of larval feeding. Metabolites assayed, included essential oils, polyphenolic groups and
foliar wax compounds and in all cases their abundance was not significantly altered by defoliation. However, the level of
foliar tannins after 3 months of larval feeding did display a trend that suggested elevated levels as the result of defoliation,
though this trend was not evident 8 months later, indicating that, if real, the response was a rapid and not a delayed induced
response. The level of foliar tannins was also negatively correlated to both average larval survival and average percentage
branch defoliation, suggesting that foliar tannins may operate as toxins and/or anti-feedants to M. privata larval feeding. 相似文献
354.
Allison J. Abell 《Behavioral ecology and sociobiology》1997,41(4):217-226
The association between spatial proximity and paternity was studied in a population of the striped plateau lizard, Sceloporus virgatus. The relationship between estimated mating success and male phenotypic traits was examined for a sample of 55 males. DNA
samples were obtained from 13 female-offspring families. The males with the closest spatial proximity to each female were
tested as possible sires within each family. Fingerprinting with two multilocus hypervariable minisatellite probes revealed
a strong correspondence between male-female spatial proximity and actual paternity. Paternity could be assigned for 72 of
the 100 hatchlings. Most hatchlings with identifiable sires were attributed to a male with the highest category of spatial
proximity to the mother. However, there was a low to moderate level of multiple paternity within clutches, and for some clutches
probable sires could not be identified even though the most likely behavioural candidates were tested. Thus, nonterritorial
males or other males lacking strong social and spatial relationships with females may achieve some degree of reproductive
success. Analysis of mating success revealed that male success increased with body size, up to a point beyond which larger
size conferred no advantage.
Received: 7 January 1997 / Accepted after revision: 16 June 1997 相似文献
355.
Brian Miller Christen Wemmer Dean Biggins Richard Reading 《Environmental management》1990,14(6):763-769
Prairie dogs (Cynomys spp.) have been poisoned throughout this century because of grazing competition with livestock. Recent evidence showed these
early claims were exaggerated, but animal control was already entrenched in government policy. As a result, ongoing government
subsidized poisoning has reduced prairie dogs to about 2% of their former distribution. The reduction of prairie dogs diminished
species diversity in the arid grasslands of North America, including the potential extinction of the black-footed ferret (Mustela nigripes). Cost-benefit analysis revealed that poisoning costs more than any grazing benefits accrued. This analysis did not consider
the long-term costs of reversing ecosystem degradation, the intangible value of biological diversity as a public benefit,
or the depletion of biotic resources as a loss of actual or potential wealth. The government presently finances the poisoning
policy and the preservation of endangered species like the black-footed ferret, two apparently conflicting programs. We, therefore,
propose an integrated management plan that considers both interests. We propose that federal monies allocated to the poisoning
program be converted into a rebate for ranchers who manage livestock while preserving the prairie dog community. This would
redirect funds and personnel already allocated to prairie dog eradication to an incentive for ranchers who manage for livestock
and wildlife. Livestock interests and grassland biotic diversity would both benefit. 相似文献
356.
畜粪污染处理与利用研究 总被引:4,自引:0,他引:4
国内外对于粪便固体物的处理主要采用焚烧法、干燥法和堆肥法等,在粪便污水处理方面主要采用厌氧消化法,它将治污、产气和综合利用相结合,使废物资源化,达到环境效益、经济效益和社会效益相统一。 相似文献
357.
Predator–prey interaction in aquatic ecosystem is one of the simplest drivers affecting the species population dynamics. Predation controls are recognized as important aspects of ecosystem husbandry and management. In this paper we investigated how predation control cause an increase in host growth in the abundance of hard clam (Meretrix lusoria) populations subject to mercury (Hg)-stressed birnavirus. Here we linked predator–prey relationships with a bioenergetic matrix population model (MPM) associated with a susceptible–infectious–mortality (SIM) model based on a host–pathogen–predator framework to quantify the predator effects on population dynamics of disease in hard clam populations. Our results indicated that relative high predation rates could promote the hard clam abundances in relation to predators that selectively captured the infected hard clam, by which the disease transmission was suppressed. The results also demonstrated that predator-induced modifications in host behavior could have potential negative or positive effects on host growth depending on relative species density and resource dynamics. The most immediate implication of this study for the management of aquatic ecosystem is that, beyond the potential for causing a growth in abundance, predation might provoke greater predictability in aquatic ecosystem species populations and thereby increase the safety of ecosystem production from stochastic environmental events. 相似文献
358.
William A. Searcy Rindy C. Anderson Stephen Nowicki 《Behavioral ecology and sociobiology》2008,62(7):1213-1216
We advocate assessing the reliability of signals of aggressive intent by eliciting aggressive signaling from a subject, giving
the subject an opportunity to attack a model, and testing whether the subject’s displays predict a subsequent attack. Using
this design, we found that most singing behaviors are poor predictors of attack in song sparrows (Melospiza melodia). Laidre and Vehrencamp (Behav Ecol Sociobiol, DOI 10.1007/s00265-007-0539-3, 2008) suggested altering our experimental design to make the model more realistic; it remains
to be seen whether such design changes would change the association between display and attack. Laidre and Vehrencamp (Behav Ecol Sociobiol, DOI 10.1007/s00265-007-0539-3, 2008) also suggested that the reliability of soft song, the one display that predicts attack
in song sparrows, can be explained by a vulnerability cost. We question the rationale for a vulnerability cost for this display
and suggest instead that soft song has a competing functions cost, in that, by using soft song to counter an intruder, a male
sacrifices other possible functions of vocal signaling. 相似文献
359.
Abstract: Inbreeding effects have been detected in captive populations of threatened species, but the extent to which these effects translate into fitness under field conditions is mostly unknown. We address this issue by comparing the performance of replicated noninbred and inbred Drosophila lines under field and laboratory conditions. We asked whether environment-dependent effects of inbreeding can be demonstrated for a field-fitness component in Drosophila , the ability of flies to locate resources, and associated the results with results on effects of inbreeding investigated in the laboratory. Inbreeding effects were evident when releases were undertaken under warm conditions, but not under cold conditions, which illustrates the environment-dependent nature of inbreeding depression. Inbreeding effects were much stronger in the field at warm temperatures than in laboratory stress tests, particularly for females. Effects of inbreeding based on performance in traditional inbreeding assays (viability, productivity) or from laboratory stress tests poorly predicted performance in the field. Inbreeding effects on resource location in the field can be strongly deleterious under some thermal conditions and involve traits not easily measured under laboratory conditions. More generally, inbreeding effects measured in captive populations may not necessarily predict their field performance, and programs to purge captive populations of deleterious alleles may not necessarily lead to fitness benefits in the wild. 相似文献
360.
Until the last decade, protecting the environment was seen as a factor contributing to human well-being, and conservation of natural ecosystems was considered to be one of the most important factors of environmental protection. Numerous studies have dealt with the benefits of natural ecosystems and in recent years even more so with ecosystem services, as well as interactions of ecosystem services with each other and with the urban and peri-urban environment. This paper suggests an approach to the spatial unity of the Florina region using basic ecosystem services identified by land use. The aim was, first, to describe the spatial distribution of basic ecosystem services and their interactions and, second, to investigate whether they form important statistical correlations with the basic features of the prefecture. A 1 km × 1 km analysis of 10 ecosystem services covering the surface of the prefecture was carried out. 相似文献