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91.
水生真菌对于河流中的落叶降解这一重要的生态系统服务有着重要的作用。然而,杀真菌剂对于参与落叶降解的水生真菌和大型无脊椎动物的影响却鲜有了解。本实验将美国红枫(Acer rubrum)的叶片在河流中进行处理(处理组)以获得微生物(细菌与真菌),或是在自来水下进行淋洗(未处理组)以模拟杀真菌剂可能带来的微生物生物量减少的情况。将处理组叶片分别置于绿钩虾属动物Hyalella azteca(端足类动物,在暴露开始时7日龄,是一种落叶分解物种)存在或不存在的环境中,在23 ℃条件下暴露于复合杀真菌剂QUILT(嘧菌酯和丙环唑)或是PRISTINE(啶酰菌胺和唑菌胺酯)培养14天。QUILT(~ 0.3 μg?L-1, 1.8 μg?L-1, 8 μg?L-1)有加速端足类动物分解落叶的趋势(不显著),却没有促进端足类动物本身生物量的同时增长,表明端足类动物对于落叶消费量的上升应该主要由于落叶营养成分的减少。PRISTINE(~ 33 μg?L-1)显著地抑制了端足类动物的生长,降低其生物量(P<0.05),在未处理组中也观察到类似结果。PRISTINE对于端足类动物生长显著的抑制作用以及随QUILT浓度升高而加快的落叶降解的趋势表明受到杀真菌剂影响的河流中落叶降解这一过程很可能被改变。在河流生态系统相关的条件下,如温度的变化和与杀虫剂混合后脉冲式的暴露,杀真菌剂对于落叶降解的影响需要进一步的研究。
精选自Adria A. Elskus, Kelly L. Smalling, Michelle L. Hladik, Kathryn M. Kuivila. Effects of 2 fungicide formulations on microbial and macroinvertebrate leaf decomposition under laboratory conditions. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2834–2844, November 2016.
DOI: 10.1002/etc.3465
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3465/full 相似文献
92.
The tendency for more closely related species to share similar traits and ecological strategies can be explained by their longer shared evolutionary histories and represents phylogenetic conservatism. How strongly species traits co-vary with phylogeny can significantly impact how we analyze cross-species data and can influence our interpretation of assembly rules in the rapidly expanding field of community phylogenetics. Phylogenetic conservatism is typically quantified by analyzing the distribution of species values on the phylogenetic tree that connects them. Many phylogenetic approaches, however, assume a completely sampled phylogeny: while we have good estimates of deeper phylogenetic relationships for many species-rich groups, such as birds and flowering plants, we often lack information on more recent interspecific relationships (i.e., within a genus). A common solution has been to represent these relationships as polytomies on trees using taxonomy as a guide. Here we show that such trees can dramatically inflate estimates of phylogenetic conservatism quantified using S. P. Blomberg et al.'s K statistic. Using simulations, we show that even randomly generated traits can appear to be phylogenetically conserved on poorly resolved trees. We provide a simple rarefaction-based solution that can reliably retrieve unbiased estimates of K, and we illustrate our method using data on first flowering times from Thoreau's woods (Concord, Massachusetts, USA). 相似文献
93.
Rodhouse TJ Ormsbee PC Irvine KM Vierling LA Szewczak JM Vierling KT 《Ecological applications》2012,22(4):1098-1113
Bats face unprecedented threats from habitat loss, climate change, disease, and wind power development, and populations of many species are in decline. A better ability to quantify bat population status and trend is urgently needed in order to develop effective conservation strategies. We used a Bayesian autoregressive approach to develop dynamic distribution models for Myotis lucifugus, the little brown bat, across a large portion of northwestern USA, using a four-year detection history matrix obtained from a regional monitoring program. This widespread and abundant species has experienced precipitous local population declines in northeastern USA resulting from the novel disease white-nose syndrome, and is facing likely range-wide declines. Our models were temporally dynamic and accounted for imperfect detection. Drawing on species-energy theory, we included measures of net primary productivity (NPP) and forest cover in models, predicting that M. lucifugus occurrence probabilities would covary positively along those gradients. Despite its common status, M. lucifugus was only detected during -50% of the surveys in occupied sample units. The overall naive estimate for the proportion of the study region occupied by the species was 0.69, but after accounting for imperfect detection, this increased to -0.90. Our models provide evidence of an association between NPP and forest cover and M. lucifugus distribution, with implications for the projected effects of accelerated climate change in the region, which include net aridification as snowpack and stream flows decline. Annual turnover, the probability that an occupied sample unit was a newly occupied one, was estimated to be low (-0.04-0.14), resulting in flat trend estimated with relatively high precision (SD = 0.04). We mapped the variation in predicted occurrence probabilities and corresponding prediction uncertainty along the productivity gradient. Our results provide a much needed baseline against which future anticipated declines in M. lucifugus occurrence can be measured. The dynamic distribution modeling approach has broad applicability to regional bat monitoring efforts now underway in several countries and we suggest ways to improve and expand our grid-based monitoring program to gain robust insights into bat population status and trend across large portions of North America. 相似文献
94.
95.
Sharmishtha Dattagupta Meredith Redding Kathryn Luley Charles Fisher 《Marine Biology》2009,156(4):779-786
Lamellibrachia luymesi and Seepiophila jonesi are co-occurring species of vestimentiferan tubeworms found at hydrocarbon seepage sites on the upper Louisiana slope of
the Gulf of Mexico. Like all vestimentiferans, they rely on internal sulfide-oxidizing symbiotic bacteria for nutrition. These
symbionts produce hydrogen ions as a byproduct of sulfide oxidation, which the host tubeworm needs to eliminate to prevent
acidosis. The hydrothermal vent tubeworm Riftia pachyptila uses a high activity of P- and V-type H+-ATPases located in its plume epithelium to excrete protons. Unlike R. pachyptila, the seep species grow a posterior root, which they can use in addition to their plumes as a nutrient exchange surface. In
this study we measured the ATPase activities of plume and root tissues collected from L. luymesi and S. jonesi, and used a combination of inhibitors to determine the relative activities of P- and V-type H+-ATPases. We found that the total H+-ATPase activity of their plumes was approximately 14 μmol h−1 g−1 wet weight, and that of their roots was between 5 and 7 μmol h−1 g−1 wet weight. These activities were more than ten times lower than those measured in R. pachyptila. We suggest that seep tubeworms might use passive channels to eliminate protons across their roots, in addition to ATP-dependant
proton pumps located in their plumes and roots. In addition, we found strong differences between the types of ATPase activities
in the plumes of L. luymesi and S. jonesi. While the H+-ATPase activity of L. luymesi plumes is dominated by P-type ATPases, S. jonesi has an unusually high activity of V-type H+-ATPases. We suggest that S. jonesi relies on its high V-type H+-ATPase activity to drive carbon dioxide uptake across its plume surface. L. luymesi, on the other hand, might rely partially on bicarbonate uptake across its root. 相似文献
96.
Tolerance to hyposalinity of the scleractinian coral S. radians was examined in a mesocosm study. Colonies of S. radians were collected from five basins in Florida Bay, USA, which occur along a northeast-to-southwest salinity gradient. Salinity
treatments were based on historical salinity records for these basins. Photophysiology of the endosymbiont Symbiodinium spp. (maximum quantum yield; F
v/F
m) was measured as an indicator of holobiont stress to hyposalinity. Colonies from each basin were assigned four salinity treatments
[The Practical Salinity Scale (PSS) was used to determine salinity. Units are not assigned to salinity values because it is
a ratio and has no unit as defined by UNESCO (UNESCO Technical papers no. 45, IAPSO Pub. Sci. No. 32, Paris, France, 1985)]
(30, 20, 15, and 10) and salinities were reduced 2 per day from ambient (30) to simulate a natural salinity decrease. Colonies
treated with salinities of 20 and 15 showed no decrease in F
v/F
m versus controls (i.e. 30), up to 5 days after reaching their target salinity. This indicates a greater ability to withstand
reduced salinity for relatively extended periods of time in S. radians compared to other reef species. Within 1 day after salinity of 10 was reached, there was a significant reduction in F
v/F
m, indicating a critical threshold for hyposaline tolerance. At the lowest treatment salinity (10), F
v/F
m for the more estuarine, northeast-basin colonies were significantly higher than the most marine southwest-basin colonies
(Twin Key Basin). Our results suggest that historical salinity ranges within basins determine coral population salinity tolerances. 相似文献
97.
Rita Hargitai Kathryn E. Arnold Márton Herényi József Prechl János Török 《Behavioral ecology and sociobiology》2009,63(6):869-882
Offspring survival can be influenced by resources allocated to eggs, which in turn may be affected by the environmental factors
the mother experiences during egg formation. In this study, we investigated whether experimentally elevated social interactions
and number of neighbouring pairs influence yolk composition of collared flycatchers (Ficedula albicollis). Social challenge was simulated by presentation of a conspecific female. Experimental females spent more time near the cage
and produced eggs with higher androgen concentration, but local breeding density did not affect yolk androgen level. Moreover,
we found that females exposed to more intra-specific interactions and those that bred at higher density produced eggs with
smaller yolk. These females may be more constrained in foraging time due to more frequent social encounters, and there might
be increased competition for food at areas of higher density. In contrast, the present study did not reveal any evidence for
the effect of social environment on yolk antioxidant and immunoglobulin levels. However, we found that yolk lutein and immunoglobulin
concentrations were related to the female’s H/L ratio. Also, yolk lutein and α-tocopherol levels showed a seasonal increase
and were positively related to the female’s plasma carotenoid level. Mothers may incur significant costs by transferring these
compounds into the eggs, thus only females in good physiological condition and those that lay eggs later, when food is probably
more abundant, could allocate higher amounts to the eggs without compromising their defence mechanisms. Our results suggest
that environmental circumstances during egg formation can influence conditions for embryonic development. 相似文献
98.
This paper explores the crucial part that faith‐based organisations (FBOs) play in acting as intermediaries between international donors and local faith communities (LFCs) implementing humanitarian relief projects for Syrian refugees. Humanitarian responses to the mounting Syrian refugee crisis have coincided with greater collaboration between international donors and LFCs. This cooperation often is facilitated by a complex web of non‐state intermediaries at the international, national, and local level. This study probes the breadth of roles of these intermediaries, drawing on primary data from case studies of two Christian intermediaries supporting Christian LFCs as they deliver aid primarily to Muslim Syrian refugees in Jordan and Lebanon. The results of the study are connected to the wider literature on LFCs in humanitarian response, revealing how intermediaries address issues of accountability, capacity‐building, impartiality, neutrality, and professionalism. The paper concludes by offering suggestions for further research on intermediaries as key actors in the localisation of humanitarian assistance. 相似文献
99.
Kathryn J. Norlock 《Journal of Agricultural and Environmental Ethics》2010,23(1-2):29-42
Our attitudes toward human culpability for environmental problems have moral and emotional import, influencing our basic capacities for believing cooperative action and environmental repair are even possible. In this paper, I suggest that having the virtue of forgivingness as a response to environmental harm is generally good for moral character, preserving us from morally risky varieties of pessimism and despair. I define forgivingness as a forward-looking disposition based on Robin Dillon’s conception of preservative forgiveness, a preparation to be deeply and abidingly accepting yet expecting human error. As with other virtues, however, preservative forgiveness is available to some of us more than others; in the second half of this paper, I consider the deep challenge posed by rational pessimism, especially on the part of those who have been given many reasons not to hope for the very moral improvements for which they strive. I conclude that for those of us with the power roles and personal resources especially conducive to environmental activism, preservative forgiveness inclines us to remain engaged in environmental activism with fellow flawed human beings, recognizing our own mutual depredations while committing us to cooperatively respond. 相似文献
100.
Lizhu Wang Kevin Wehrly James E. Breck Lidia Szabo Kraft 《Environmental management》2010,46(3):471-483
Assessment of lake impairment status and identification of threats’ type and source is essential for protection of intact,
enhancement of modified, and restoration of impaired lakes. For regions in which large numbers of lakes occur, such assessment
has usually been done for only small fractions of lakes due to resource and time limitation. This study describes a process
for assessing lake impairment status and identifying which human disturbances have the greatest impact on each lake for all
lakes that are 2 ha or larger in the state of Michigan using readily available, georeferenced natural and human disturbance
databases. In-lake indicators of impairment are available for only a small subset of lakes in Michigan. Using statistical
relationships between the in-lake indicators and landscape natural and human-induced measures from the subset lakes, we assessed
the likely human impairment condition of lakes for which in-lake indicator data were unavailable using landscape natural and
human disturbance measures. Approximately 92% of lakes in Michigan were identified as being least to marginally impacted and
about 8% were moderately to heavily impacted by landscape human disturbances. Among lakes that were heavily impacted, more
inline lakes (92%) were impacted by human disturbances than disconnected (6%) or headwater lakes (2%). More small lakes were
impacted than medium to large lakes. For inline lakes, 90% of the heavily impacted lakes were less than 40 ha, 10% were between
40 and 405 ha, and 1% was greater than 405 ha. For disconnected and headwater lakes, all of the heavily impacted lakes were
less than 40 ha. Among the anthropogenic disturbances that contributed the most to lake disturbance index scores, nutrient
yields and farm animal density affected the highest number of lakes, agricultural land use affected a moderate number of lakes,
and point-source pollution and road measures affected least number of lakes. Our process for assessing lake condition represents
a significant advantage over other routinely used methods. It permits the evaluation of lake condition across large regions
and yields an overall disturbance index that is a physicochemical and biological indicator weighted sum of multiple disturbance
factors. The robustness of our approach can be improved with increased availability of high-resolution disturbance datasets. 相似文献