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371.
Honeybee colonies are declining in some parts of the world. This may have important consequences for the pollination of crops
and native plant species. In Spain, as in other parts of Europe, land abandonment has led to a decrease in the number of non
professional beekeepers, which aggravates the problem of honeybee decline as a result of bee diseases In this study, we investigated
the effects of honeybees on the pollination of three native plant species in northern Spain, namely wildcherry Prunus avium L., hawthorn Crataegus monogyna Jacq., and bilberry Vaccinium myrtillus L. We quantified fruit set of individuals from the target species along transects established from an apiary outwards. Half
the samples were bagged in a nylon mesh to avoid insect pollination. Mixed-effects models were used to test the effect of
distance to the apiary on fruit set in non-bagged samples. The results showed a negative significant effect of distance from
the apiary on fruit set for hawthorn and bilberry, but no significant effects were detected for wildcherry. This suggests
that the use of honeybees under traditional farming practices might be a good instrument to increase fruit production of some
native plants. This may have important consequences for wildlife conservation, since fruits, and bilberries in particular,
constitute an important feeding resource for endangered species, such as the brown bear Ursus arctos L. or the capercaillie Tetrao urogallus cantabricus L. 相似文献
372.
Nicolas A.O. Morin Patrik L. Andersson Sarah E. Hale Hans Peter H. Arp 《环境科学学报(英文版)》2017,29(12):115-132
Flame retardants in commercial products eventually make their way into the waste stream.Herein the presence of flame retardants in Norwegian landfills, incineration facilities and recycling sorting/defragmenting facilities is investigated. These facilities handled waste electrical and electronic equipment(WEEE), vehicles, digestate, glass, combustibles, bottom ash and fly ash. The flame retardants considered included polybrominated diphenyl ethers(∑BDE-10) as well as dechlorane plus, polybrominated biphenyls, hexabromobenzene,pentabromotoluene and pentabromoethylbenzene(collectively referred to as ∑FR-7). Plastic,WEEE and vehicles contained the largest amount of flame retardants(∑BDE-10: 45,000–210,000 μg/kg; ∑FR-7: 300–13,000 μg/kg). It was hypothesized leachate and air concentrations from facilities that sort/defragment WEEE and vehicles would be the highest. This was supported for total air phase concentrations(∑BDE-10: 9000–195,000 pg/m~3 WEEE/vehicle facilities, 80–900 pg/m~3 in incineration/sorting and landfill sites), but not for water leachate concentrations(e.g., ∑BDE-10: 15–3500 ng/L in WEEE/Vehicle facilities and 1–250 ng/L in landfill sites). Landfill leachate exhibited similar concentrations as WEEE/vehicle sorting and defragmenting facility leachate. To better account for concentrations in leachates at the different facilities, waste-water partitioning coefficients, Kwastewere measured(for the first time to our knowledge for flame retardants). WEEE and plastic waste had elevated Kwastecompared to other wastes, likely because flame retardants are directly added to these materials. The results of this study have implications for the development of strategies to reduce exposure and environmental emissions of flame retardants in waste and recycled products through improved waste management practices. 相似文献
373.
374.
Dominance assessment is important in mating competition across a variety of species, but little is known about how individuals’
own quality affects their assessment of potential rivals. We conducted two studies to test whether men’s own dominance affects
their attentiveness to a putative dominance signal, vocal masculinity, when assessing competitors. Study I examined dominance
ratings made by men in relation to their self-rated physical dominance. Study II examined dominance ratings made by men in
relation to objective measures of their physical dominance, including size, strength, testosterone, and physical aggressiveness.
Vocal masculinity strongly affected dominance ratings, but a man’s own dominance did not alter his attention to vocal masculinity
when assessing dominance. However, men who rated themselves high on physical dominance rated the voices of other men lower
on dominance and reported more sex partners (study I). Men with intermediate testosterone concentrations rated the voices
of other men lower on dominance (study II). These results confirm the effect of vocal masculinity on dominance perceptions,
provide further evidence that dominance is relevant to mating success, and shed new light on how men assess the dominance
of rivals and potential allies. Our results suggest that attention to dominance signals may depend less on the observer’s
own dominance in species with coalitional aggression, where individuals must assess others not only in relation to themselves
but also in relation to each other. Among men, the effect of a deep, masculine voice on perceptions of dominance appears to
be robust and unmediated by the formidability of the listener. 相似文献
375.
Potential synergies of the main current forestry efforts and climate change mitigation in Central Africa 总被引:1,自引:0,他引:1
In Central Africa, important carbon stocks are stored in natural forest stands, while activities that modify the carbon storage
occur in the forest landscape. Besides clean development mechanisms, the reduction of emission through deforestation and degradation
(REDD) initiative is viewed as one way to mitigate climate change. Important forest habitat protection activities have already
been implemented with the aim of conserving the biodiversity of the region in a sustainable manner. The main causes of land
use changes in the region are small holder subsistence practices and logging activities. Agricultural production has low productivity
levels and therefore investments in improved agricultural techniques can both reduce pressure on existing forests and perhaps
allow for the reforestation of existing degraded lands. The logging industry is dominated by large, industrial scale, logging
operations performing selective logging of specific species and large trees. The adoption of improved forest management practices
can reduce the impact of such logging on the ecological integrity and carbon stocks. Some efforts to engage in the carbon
market have begun in the region. Further research is needed into the types of projects that will most likely become successful
in the region and what locations will offer the greatest benefits. 相似文献
376.
Predicting Invasions of Woody Plants Introduced into North America 总被引:27,自引:0,他引:27
Plant species continue to be introduced in North America for various purposes. If the trend continues, it is probable that some will escape cultivation and become invasive in native ecosystems. We present a retrospective analysis of several structural, life history, and biogeographical attributes of woody plants introduced in North America to determine which traits characterize species that have and have not invaded. Predictive models derived from discriminant analysis correctly classified 86.2% of the species in cross-validation, whereas those derived from classification and regression trees classified 76% correctly. From these models we created a hierarchical predictive tree that allows the user to divide species into three categories: admit (low risk of invasiveness), deny admission (high risk of invasiveness), or delay admission for further analyses and/or monitor intensively (risk cannot adequately be assessed based on only the included attributes). We recommend that species that are highly invasive elsewhere not be allowed into the U.S. and that a more conservative introduction policy using a hierarchical predictive method be employed. 相似文献
377.
Sarah Mellish Jillian C. Ryan Elissa L. Pearson Michelle R. Tuckey 《Conservation biology》2019,33(1):40-52
Zoos and aquariums are increasingly incorporating conservation education into their mission statements and visitor experiences to address global biodiversity loss. To advance knowledge and practice in the field, research is being conducted to evaluate the effect of zoo conservation-education experiences on visitor psychosocial outcomes (e.g., knowledge, attitude, emotions, motivations, behavior). Following recent discussions among scholars and practitioners concerning logistical and methodological challenges that likely undermine the conclusions of such research, we identified and reviewed the methods and reporting practices in peer-reviewed articles published in English from May 1998 to June 2016 that focused on adult visitor samples (47 articles, 48 studies). We examined elements of internal, external, construct, and statistical conclusion validity. Methodological quality of quantitative methods and reporting practices was determined using the Effective Public Health Practice Project Quality Assessment Tool. Each study was coded as either strong (no weak ratings), moderate (1 weak rating), or weak (≥2 weak ratings). The quantitative methods of 83.3% of studies were weak. The remaining 16.7% had methods of moderate quality. Using an existing checklist, we also assessed the quality and rigor of qualitative methods and reporting practices and found that some aspects of these methods were reported more comprehensively than others. For example, 69.6% of articles discussed methods for identifying key themes from the data, whereas only 34.8% reported how data verification was performed. We suggest increased application of intensive longitudinal methods (e.g., daily diary) to strengthen self-reported data, experimental and repeated-measures designs, and mixed-methods approaches. Our findings and recommendations could strengthen and guide the research and evaluation agenda for the field and ultimately enhance the contribution zoos make to global biodiversity conservation. 相似文献
378.
Sarah J Converse Gary C White Kerry L Farris Steve Zack 《Ecological applications》2006,16(5):1717-1729
Forest fuel reduction treatments are increasingly used by managers to reduce the risk of high-severity wildfire and to manage changes in the ecological function of forests. However, comparative ecological effects of the various types of treatments are poorly understood. We examined short-term patterns in small-mammal responses to mechanical thinning, prescribed-fire, and mechanical thinning/prescribed-fire combination treatments at eight different study areas across the United States as a part of the National Fire and Fire Surrogate (FFS) Project. Research questions included: (1) do treatments differ in their effect on small mammal densities and biomass? and (2) are effects of treatments consistent across study areas? We modeled taxa-specific densities and total small-mammal biomass as functions of treatment types and study area effects and ranked models based on an information-theoretic model selection criterion. Small-mammal taxa examined, including deer mice (Peromyscus maniculatus), yellow-pine chipmunks (Tamias amoenus), and golden-mantled ground squirrels (Spermophilus lateralis), as well as all Peromyscus and Tamias species, had top-ranked models with responses varying both by treatment type and study area. In each of these cases, the top-ranked model carried between 69% and 99% of the total weight in the model set, indicating strong support for the top-ranked models. However, the top-ranked model of total small-mammal biomass was a model with biomass varying only with treatment (i.e., treated vs. untreated), not by treatment type or study area; again, this model had strong support, with 75% of the total model weight. Individual species and taxa appear to have variable responses to fuel reduction treatment types in different areas; however, total small-mammal biomass appears generally to increase after any type of fuel reduction. These results suggest that there is substantial variability in taxa-specific responses to treatments and indicate that adaptive management policies may be necessary when applying fuel reduction treatments in areas where management of small-mammal populations is of interest. Adaptive management can be used by managers who are conducting fuel reduction treatments to reduce uncertainty as to which treatments are locally optimal for meeting objectives for the management of small-mammal populations. 相似文献
379.
380.
Nicholas Lench Angela Barrett Sarah Fielding Fiona McKay Melissa Hill Lucy Jenkins Helen White Lyn S. Chitty 《黑龙江环境通报》2013,33(6):555-562
Recently, we have witnessed the rapid translation into clinical practice of non-invasive prenatal testing for the common aneuploidies, most notably within the United States and China. This represents a lucrative market with testing being driven by companies developing and offering their services. These tests are currently aimed at women with high/medium-risk pregnancies identified by serum screening and/or ultrasound scanning. Uptake has been impressive, albeit limited to the commercial sector. However, non-invasive prenatal diagnosis (NIPD) for single-gene disorders has attracted less interest, no doubt because this represents a much smaller market opportunity and in the majority of cases has to be provided on a bespoke, patient or disease-specific basis. The methods and workflows are labour-intensive and not readily scalable. Nonetheless, there exists a significant need for NIPD of single-gene disorders, and the continuing advances in technology and data analysis should facilitate the expansion of the NIPD test repertoire. Here, we review the progress that has been made to date, the different methods and platform technologies, the technical challenges, and assess how new developments may be applied to extend testing to a wider range of genetic disorders. © 2013 John Wiley & Sons, Ltd. 相似文献