全文获取类型
收费全文 | 2249篇 |
免费 | 36篇 |
国内免费 | 19篇 |
专业分类
安全科学 | 77篇 |
废物处理 | 78篇 |
环保管理 | 387篇 |
综合类 | 360篇 |
基础理论 | 560篇 |
环境理论 | 4篇 |
污染及防治 | 570篇 |
评价与监测 | 154篇 |
社会与环境 | 97篇 |
灾害及防治 | 17篇 |
出版年
2023年 | 22篇 |
2022年 | 24篇 |
2021年 | 30篇 |
2020年 | 34篇 |
2019年 | 30篇 |
2018年 | 53篇 |
2017年 | 54篇 |
2016年 | 53篇 |
2015年 | 58篇 |
2014年 | 65篇 |
2013年 | 164篇 |
2012年 | 86篇 |
2011年 | 123篇 |
2010年 | 94篇 |
2009年 | 104篇 |
2008年 | 108篇 |
2007年 | 131篇 |
2006年 | 100篇 |
2005年 | 90篇 |
2004年 | 80篇 |
2003年 | 79篇 |
2002年 | 90篇 |
2001年 | 60篇 |
2000年 | 37篇 |
1999年 | 32篇 |
1998年 | 25篇 |
1997年 | 29篇 |
1996年 | 28篇 |
1995年 | 30篇 |
1994年 | 29篇 |
1993年 | 19篇 |
1992年 | 21篇 |
1991年 | 22篇 |
1990年 | 18篇 |
1989年 | 16篇 |
1988年 | 20篇 |
1987年 | 16篇 |
1986年 | 21篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 13篇 |
1980年 | 10篇 |
1979年 | 17篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1954年 | 8篇 |
排序方式: 共有2304条查询结果,搜索用时 109 毫秒
891.
Martin?OlofssonEmail author Sven?Jakobsson Christer?Wiklund 《Behavioral ecology and sociobiology》2012,66(2):209-215
Morphological and behavioural traits can serve as anti-predator defence either by reducing detection or recognition risks,
or by thwarting initiated attacks. The latter defence is secondary and often involves a ‘startle display’ comprising a sudden
release of signals targeting more than one sensory modality. A suggested candidate for employing a multimodal defence is the
peacock butterfly, Inachis io, which, by wing-flicking suddenly, produces sonic and ultrasonic sounds and displays four large eyespots when attacked. The
eyespots make small birds retreat, but whether the sounds produced thwart predator attacks is largely unknown. Peacocks hibernate
as adults in dark wintering sites and employ their secondary defence upon encounter with small rodent predators during this
period. In this study, we staged predator–prey encounters in complete darkness in the laboratory between wild mice, Apodemus flavicollis and Apodemus sylvaticus, and peacocks which had their sound production intact or disabled. Results show that mice were more likely to flee from sound-producing
butterflies than from butterflies which had their sound production disabled. Our study presents experimental evidence that
the peacock butterfly truly employs a multimodal defence with different traits targeting different predator groups; the eyespots
target birds and the sound production targets small rodent predators. 相似文献
892.
Hassan FM Taylor WD Al-Taee MM Al-Fatlawi HJ 《Journal of environmental biology / Academy of Environmental Biology, India》2010,31(3):343-350
Seasonal variations in phytoplankton abundance and their composition were studied at five stations in the middle region (between Al-Hindiya barrage to Kifil City) of the Euphrates River in Iraq between March, 2004, and February, 2005. A total 151 taxa of phytoplankton were identified, belonging to Bacillariophyceae (98), Chlorophyceae (33), Cyanophyceae (14), Euglenophyceae (2), Xanthophyceae (2), and Dinophyceae (2). The total abundance of phytoplankton cells varied from 136 to 5312 cells l(-1) with maxima in spring and fall. Bacillariophyceae were the most abundant group at all stations. Some species of phytoplankton occurred continuously during the study period (Cyclotella ocellata, C. meneghiana, Cocconeis placentula, Nitzchia spp, Meringosphaera spinosa). The study recorded four species as new records for Iraqi. The phytoplankton was indicative of oligotrophic conditions although it showed some signs of organic pollution near cities. 相似文献
893.
Ingo Schlupp Rüdiger Riesch Michael Tobler Martin Plath Jakob Parzefall Manfred Schartl 《Behavioral ecology and sociobiology》2010,64(11):1849-1855
Female choice can often drive the elaboration of male traits, leading to the evolution of secondary sexual traits. In the
Mexican molly, Poecilia sphenops (Poeciliidae), some males exhibit a mustache-like structure on the upper maxilla, the function of which has not been previously
recognized. The mustache consists of epidermal outgrowths at the edge of the scales that appear to have no sensory function.
Trait expression varies within as well as among populations of P. sphenops, but is not linked to male body size polymorphism. In mate choice experiments, female P. sphenops exhibited a visual mating preference for males with mustaches, suggesting that the trait may be sexually selected. Since
the mating behavior of P. sphenops involves contact of the male’s snout and the female genital region prior to copulation, we hypothesize that the mustache
may also convey tactile signals to the female. 相似文献
894.
Robin C. Puett Andrew B. Lawson Allan B. Clark James R. Hebert Martin Kulldorff 《Environmental and Ecological Statistics》2010,17(3):303-316
Many statistical tests have been developed to assess the significance of clusters of disease located around known sources
of environmental contaminants, also known as focused disease clusters. The majority of focused-cluster tests were designed
to detect a particular spatial pattern of clustering, one in which the disease cluster centers around the pollution source
and declines in a radial fashion with distance. However, other spatial patterns of environmentally related disease clusters
are likely given that the spatial dispersion patterns of environmental contaminants, and thus human exposure, depend on a
number of factors (i.e., meteorology and topography). For this study, data were simulated with five different spatial patterns
of disease clusters, reflecting potential pollutant dispersion scenarios: (1) a radial effect decreasing with increasing distance,
(2) a radial effect with a defined peak and decreasing with distance, (3) a simple angular effect, (4) an angular effect decreasing
with increasing distance and (5) an angular effect with a defined peak and decreasing with distance. The power to detect each
type of spatially distributed disease cluster was evaluated using Stone’s Maximum Likelihood Ratio Test, Tango’s Focused Test,
Bithell’s Linear Risk Score Test, and variations of the Lawson–Waller Score Test. Study findings underscore the importance
of considering environmental contaminant dispersion patterns, particularly directional effects, with respect to focused-cluster
test selection in cluster investigations. The effect of extra variation in risk also is considered, although its effect is
not substantial in terms of the power of tests. 相似文献
895.
The breeding performance of higher predators has often been used to monitor fluctuations in the abundance of important prey
stocks in marine ecosystems. The development of electronic data-loggers in recent years has also provided the opportunity
of using wide-ranging marine animals to measure physical oceanographic conditions. In this study, time–depth recorders (TDRs)
programmed to record temperature were deployed on female Antarctic fur seals (Arctocephalus gazella) at Bird Island, South Georgia (54°00′S; 38°02′W) during the breeding seasons 1994 to 1998. Temperature sensors had relatively
slow response times, and thermal radiation errors occurred during the day when seals spent a large proportion of their time
at the surface. Nevertheless, measurements provided temperature–depth profiles which were typical of the vertical stratification
of the ocean. During the early stages of a foraging trip temperature increased, suggesting that fur seals travelled northwards
from South Georgia towards the warmer waters of the Polar Front. In addition, higher temperatures were recorded by females
that remained at sea for longer, implying that these individuals also travelled further. Mean sea-surface temperature (SST)
increased from ∼1 to 4 °C from December to March and agreed with SSTs from ship, buoy and satellite. Future studies on marine
mammals which combine satellite tracking with oceanographic measurements are likely to provide valuable information on biophysical
aspects of the ocean.
Received: 16 June 1998 / Accepted: 13 February 1999 相似文献
896.
Predicting changes in the Antarctic krill, Euphausia superba, population at South Georgia 总被引:1,自引:0,他引:1
Variability in the Southern Ocean is frequently reflected in changes in the abundance of Antarctic krill Euphausia superba and subsequent effects on dependent predators. However, the nature and consequences of changes in krill population dynamics
that accompany fluctuations in its abundance are essentially unknown. A conceptual model, developed from quantitative measures
of krill length in the diet of predators at South Georgia from 1991 to 1997, allowed predictions to be made about the abundance
and population structure of krill in 1998 and the consequences for predators. Consistent with model predictions, in 1998 there
was a serial change in krill population structure, low krill biomass and low reproductive performance of predators. The change
in the modal size of krill, from 56 mm in December to 42 mm in March, was apparently a result of the transport of krill into
the region. This is the first occasion when the future status and structure of the krill population at South Georgia has been
successfully predicted. By representing local krill population dynamics, which may also reflect large-scale physical and biological
processes, predators have a potential key role as indicators of environmental variation in the Southern Ocean at a range of
spatial scales.
Received: 6 March 1999 / Accepted: 3 September 1999 相似文献
897.
Thomas Artiss Wesley M. Hochachka Kathy Martin 《Behavioral ecology and sociobiology》1999,46(6):429-434
For several species of birds, high rates of male vigilance are correlated with high rates of female foraging. This relationship
is thought to ultimately result in higher reproductive success for females paired with highly vigilant males. However, previous
research has not examined the behavioural mechanism that produces the correlation between male vigilance and rates of female
foraging. Foraging females may take advantage of vigilance that males are using for other purposes. Alternatively, the purpose
of male vigilance may be to increase females' ability to forage. We examined these alternatives by testing whether vigilance
preceded or followed bouts of female foraging more often than would occur by chance alone, using simultaneous behaviour observations
of pre-incubation pairs of white-tailed ptarmigan (Lagopus leucurus). Our results indicate that each member of a pair may influence the behaviour of the other. Females were more likely to initiate
foraging bouts after males became vigilant than if their mate remained non-vigilant. Moreover, non-vigilant males were more
likely to become vigilant if their mate was foraging than if she was engaged in some other activity. Despite the possibility
that a sexual conflict exists as each member of a pair attempts to maximize its fitness, both sexes behave as though a major
role of male vigilance is to enhance female foraging opportunities.
Received: 3 May 1999 / Received in revised form: 14 June 1999 / Accepted: 16 June 1999 相似文献
898.
A Framework for Evaluating the Effects of Human Factors on Wildlife Habitat: the Case of Giant Pandas 总被引:10,自引:0,他引:10
Jianguo Liu ‡ Zhiyun Ouyang † William W. Taylor Richard Groop § Yingchun Tan and Heming Zhang 《Conservation biology》1999,13(6):1360-1370
Abstract: To address the complex interactions between humans and wildlife habitat, we developed a conceptual framework that links human factors with forested landscapes and wildlife habitat. All the components in the framework are integrated into systems models that analyze the effects of human factors and project how wildlife habitat would change under different policy scenarios. As a case study, we applied this framework to the Wolong Nature Reserve in Sichuan Province (southwestern China), the largest home of the giant panda ( Ailuropoda melanoleuca ). We collected ecological and socioeconomic data with a combination of various methods ( field observations, aerial photographs, government documents and statistics, interviews, and household surveys) and employed geographic information systems and systems modeling to analyze and integrate the data sources. Human population size has increased by 66% and the number of households in the reserve has increased by 115% since 1975, when the reserve was established. During the same period, the quality and quantity of the giant panda habitat dramatically decreased because of increasing human activities such as fuelwood collection. Systems modeling predicted that under the status quo, human population in the reserve would continue to grow and cause more destruction of the remaining panda habitat, whereas reducing human birth rates and increasing human emigration rates would lower human population size and alleviate human impacts on the panda habitat. Furthermore, our simulations and surveys suggested that policies encouraging the emigration of young people would be more effective and feasible than relocating older people in reducing human population size and conserving giant panda habitat in the reserve. 相似文献
899.
900.
Tung V. Nguyen Martin Reinhard Huiting Chen Karina Y.-H. Gin 《Environmental science and pollution research international》2016,23(11):10382-10392
Transport and fate of perfluoro- and polyfluoroalkyl substances (PFASs) in an urban water body that receives mainly urban runoff was investigated. Water, suspended solids, and sediment samples were collected during the monsoon (wet) and inter-monsoon (dry) season at different sites and depths. Samples were analyzed for C7 to C12 perfluoroalkyl carboxylate homologues (PFCAs) (PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA), perfluorohexane, perfluorooctane, and 6:2-fluorotelomer sulfonate (PFHxS, PFOS, and 6:2FtS, respectively), perfluorooctane sulfonamide (FOSA), N-ethyl FOSA (sulfluramid), N-ethyl sulfonamidoethanol (N-EtFOSE), and N-methyl and N-ethyl sulfonamidoacetic acid (N-EtFOSAA and N-MeFOSAA, respectively). Concentrations in wet samples were only slightly higher. The sum total PFAS (ΣPFAS) concentrations dissolved in the aqueous phase and sorbed to suspended solids (SS) ranged from 107 to 253 ng/L and 11 to 158 ng/L, respectively. PFOA, PFOS, PFNA, PFHxS, and PFDA contributed most (approximately 90 %) to the dissolved ΣPFASs. N-EtFOSA dominated the particulate PFAS burden in wet samples. K D values of PFOA and PFOS calculated from paired SS and water concentrations varied widely (1.4 to 13.7 and 1.9 to 98.9 for PFOA and PFOS, respectively). Field derived K D was significantly higher than laboratory K D suggesting hydrophobic PFASs sorbed to SS resist desorption. The ΣPFAS concentrations in the top sedimentary layer ranged from 8 to 42 μg/kg and indicated preferential accumulation of the strongly sorbing long-chain PFASs. The occurrence of the metabolites N-MeFOSAA, N-EtFOSAA and FOSA in the water column and sediments may have resulted from biological or photochemical transformations of perfluorooctane sulfonamide precursors while the absence of FOSA, N-EtFOSA and 6:2FtS in sediments was consistent with biotransformation. 相似文献