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151.
Using a common commensal bacterium in endangered Takahe as a model to explore pathogen dynamics in isolated wildlife populations 下载免费PDF全文
Brett D. Gartrell Patrick J. Biggs Nicola J. Nelson Jonathan C. Marshall Laryssa Howe Matthew G.M. Balm Nigel P. French 《Conservation biology》2015,29(5):1327-1336
Predicting and preventing outbreaks of infectious disease in endangered wildlife is problematic without an understanding of the biotic and abiotic factors that influence pathogen transmission and the genetic variation of microorganisms within and between these highly modified host communities. We used a common commensal bacterium, Campylobacter spp., in endangered Takahe (Porphyrio hochstetteri) populations to develop a model with which to study pathogen dynamics in isolated wildlife populations connected through ongoing translocations. Takahe are endemic to New Zealand, where their total population is approximately 230 individuals. Takahe were translocated from a single remnant wild population to multiple offshore and mainland reserves. Several fragmented subpopulations are maintained and connected through regular translocations. We tested 118 Takahe from 8 locations for fecal Campylobacter spp. via culture and DNA extraction and used PCR for species assignment. Factors relating to population connectivity and host life history were explored using multivariate analytical methods to determine associations between host variables and bacterial prevalence. The apparent prevalence of Campylobacter spp. in Takahe was 99%, one of the highest reported in avian populations. Variation in prevalence was evident among Campylobacter species identified. C. sp. nova 1 (90%) colonized the majority of Takahe tested. Prevalence of C. jejuni (38%) and C. coli (24%) was different between Takahe subpopulations, and this difference was associated with factors related to population management, captivity, rearing environment, and the presence of agricultural practices in the location in which birds were sampled. Modeling results of Campylobacter spp. in Takahe metapopulations suggest that anthropogenic management of endangered species within altered environments may have unforeseen effects on microbial exposure, carriage, and disease risk. Translocation of wildlife between locations could have unpredictable consequences including the spread of novel microbes between isolated populations. 相似文献
152.
Edward F. Shultz Axel Fehrenbacher Frank E. Pfefferkorn Michael R. Zinn Nicola J. Ferrier 《Journal of Manufacturing Processes》2013,15(1):25-33
In this paper a shared control strategy is presented that allows a skilled operator to identify irregularities that occur during robotic friction stir welding (FSW) and assist the robotic system in producing an appropriate response. Human operators are adept at identifying disturbances; however, the complexity of the friction stir welding process makes it difficult for the operator to respond. While examining the capabilities of shared control in friction stir welding, this paper focuses on responding to defects that are caused by a lack of workpiece material during butt welding, such as gaps. A compensation strategy is presented that combines the human operator's perceptual strengths with an automated procedure for adjustment of the process parameters (i.e. travel angle and plunge depth). Experiments comparing four control strategies are performed while welding 5083-H116 aluminum. Through our experiments we demonstrate that if the FSW control task is appropriately shared between the human operator and the computer control system, the weld quality (strength) can be improved (from 9 ksi to 31 ksi for a gap size of 2.5 mm) as compared with the nominal case in which no corrections are made. 相似文献
153.
Palmate Santosh S. Wagner Paul D. Fohrer Nicola Pandey Ashish 《Environmental Modeling and Assessment》2022,27(2):275-293
Environmental Modeling & Assessment - Uncertainty in future land use change modelling is crucial to study as it may result in varying spatial characteristics and features of the model. An... 相似文献
154.
Assessing river flood risk and adaptation in Europe—review of projections for the future 总被引:3,自引:0,他引:3
Zbigniew W. Kundzewicz Nicola Lugeri Rutger Dankers Yukiko Hirabayashi Petra Döll Iwona Pińskwar Tomasz Dysarz Stefan Hochrainer Piotr Matczak 《Mitigation and Adaptation Strategies for Global Change》2010,15(7):641-656
Flood damages have exhibited a rapid upward trend, both globally and in Europe, faster than population and economic growth.
Hence, vigorous attempts of attribution of changes have been made. Flood risk and vulnerability tend to change over many areas,
due to a range of climatic and nonclimatic impacts whose relative importance is site-specific. Flooding is a complex phenomenon
and there are several generating mechanisms, among others intense and/or long-lasting precipitation, snowmelt, ice jam. Projected
climate-driven changes in future flood frequency are complex, depending on the generating mechanism, e.g., increasing flood
magnitudes where floods result of heavy rainfall and possibly decreasing magnitudes where floods are generated by spring snowmelt.
Climate change is likely to cause an increase of the risk of riverine flooding across much of Europe. Projections of flood
hazard in Europe based on climatic and hydrological models, reviewed in this paper, illustrate possible changes of recurrence
of a 100-year flood (with probability of exceedance being 1-in-100 years) in Europe. What used to be a 100-year flood in the
control period is projected to become either more frequent or less frequent in the future time horizon of concern. For a large
part of the continent, large flooding is projected to become more commonplace in future, warmer climate. Due to the large
uncertainty of climate projections, it is currently not possible to devise a scientifically-sound procedure for redefining
design floods (e.g. 100-year flood) in order to adjust flood defenses. For the time being, we recommend to adjust design floods
using a “climate change factor” approach. 相似文献
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Valentina Ciardelli Nicola Rizzo Antonio Farina Marisa Vitarelli Paola Boni Luciano Bovicelli 《黑龙江环境通报》2001,21(7):586-588
The relationship between fetal renal function (FRF) and fetal serum beta2-microglobulin (B2MG) was investigated by comparing its value in 112 unaffected fetuses with that of 23 fetuses presenting with urinary tract malformations (UTM). Fetal serum level of B2MG was totally unrelated to gestational age; its value increased in cases of severe impairment of FRF but was similar to controls in all mild uropathies (p<0.05). Evaluating serum B2MG could be beneficial in fetuses with severe renal damage, but is of no use in unilateral UTM since only the global FRF is tested and not the function of each single kidney. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
158.
Bert Hölldobler Malu Obermayer Nicola J. R. Plowes Brian L. Fisher 《Die Naturwissenschaften》2014,101(7):527-532
Fisher and Robertson (Insect Soc 46: 78–83, 1999) discovered the production of silk-like secretions emerging from slit-shaped openings along the anterior margin of the ventral hypostoma of Melissotarsus ant workers. The current histological study describes a hitherto unknown hypostomal gland from which this silk-like substance originates. In addition, this study describes a new basitarsal gland in the three pairs of legs of Melissotarsus workers. 相似文献
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