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111.
Ismael Galván 《Behavioral ecology and sociobiology》2008,63(2):303-311
Animal ritualized displays have been classically viewed as behavioral characters that decrease signal ambiguity or that facilitate
the evaluation of costly exhibitions. It has been shown that their prevalence and level of complexity across species can reflect
phylogenetic relationships between them, but the adaptive function of these behavioral traits is poorly known. Here, I hypothesize
that, given that the efficacy of visual displays basically depends on conspicuousness and level of performance, species with
low levels of conspicuousness may be forced to perform more complex varieties of a given display to get the same signal efficiency
than other more conspicuous species. Thus, the evolution of display complexity, considered as the level of exaggeration of
ritualized movements, may be explained as an adaptive trait and not only by phylogenetic inertia. I illustrate and test this
hypothesis with the case of black-and-white plumage patches of pelecaniform birds. As predicted, there was a negative correlation
between level of complexity and species conspicuousness (proportion of unmelanized plumage) for two different social displays.
This indicates that classical ideas on the adaptiveness of ritualized displays should be considered to understand the present
variation in signal form across species, which sheds light on the evolution of multiple signals. 相似文献
112.
Performance Evaluation of the SLEUTH Model in the Shenyang Metropolitan Area of Northeastern China 总被引:5,自引:0,他引:5
Xiaoqing Wu Yuanman Hu Hong S. He Rencang Bu Jeff Onsted Fengming Xi 《Environmental Modeling and Assessment》2009,14(2):221-230
Performance evaluation is crucial for the development and improvement of an urban cellular automata model, such as SLEUTH.
In this paper, we employed multiple methods for map comparison and model validation to evaluate the simulation performance
of the SLEUTH urban growth model in the Shenyang metropolitan area of China. These multiple methods included the relative
operating characteristic (ROC) curve statistic, multiple-resolutions error budget, and landscape metrics. They were used to
quantitatively examine model performance in terms of the amount and spatial location of urban development, urban spatial pattern
and prediction ability. The assessment results showed that SLEUTH performed well in the way of the quantitative simulation
of urban growth for this case study. Similar to other urban growth models, however, the simulation accuracy for spatial location
of new development at the pixel scale and urban spatial pattern still needs to be improved greatly. These inaccuracies might
be attributed to the structure and nature of SLEUTH, local urban development characteristics, and the temporal and spatial
scale of its application. Finally, many valuable suggestions had been put forward to improve simulation performance of SLEUTH
model for spatial location of urban development in the Shenyang metropolitan area. 相似文献
113.
Tobias Weil Katharina Hoffmann Johannes Kroiss Erhard Strohm Judith Korb 《Die Naturwissenschaften》2009,96(2):315-319
In social insects, it is assumed that signals of the queen inform nestmates about her reproductive status. Thus, workers forego
their own reproduction if the queen signals high fertility. In hemimetabolous termites, little is known about reproductive
inhibition, but evidence exists for a royal-pair control. Workers of lower termites exhibit a high developmental flexibility
and are potentially able to become reproductives, but the presence of a fertile reproductive restrains them from reaching
sexual maturity. The nature of this control, however, remains unknown. Here, we report on qualitative differences in cuticular
hydrocarbon profiles between queens and workers of the basal drywood termite Cryptotermes secundus. Queens were characterized by a shift to long-chained and branched hydrocarbons. Most remarkably, similar chemical patterns
are regarded as fertility cues of reproductives in social Hymenoptera. This might suggest that both groups of social insects
convergently evolved similar chemical signatures. The present study provides deeper insights into how termites might have
socially exploited these signatures from sexual communication in their cockroach-like ancestor.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
114.
近年来,各地纷纷兴建大型火车站房,这类建筑中的楼盖大多为大跨、轻质和低阻尼结构,本文基于人体舒适度考虑,对这些大跨楼盖进行振动舒适度的分析.首先,建立某大型火车站房的整体有限元模型,研究这类建筑中大跨楼盖的振动特性;随后,对楼盖在各种不利工况人群荷载作用下的振动舒适度进行分析;最后,在已有研究的基础上,提出了大跨楼盖多... 相似文献
115.
Tânia Rodrigues Pereira Ramos Maria Isabel Gomes Ana Paula Barbosa-Póvoa 《Waste management (New York, N.Y.)》2013,33(8):1691-1703
This research has been motivated by a real-life problem of a waste cooking oil collection system characterized by the existence of multiple depots with an outsourced vehicle fleet, where the collection routes have to be plan. The routing problem addressed allows open routes between depots, i.e., all routes start at one depot but can end at the same or at a different one, depending on what minimizes the objective function considered. Such problem is referred as a Multi-Depot Vehicle Routing Problem with Mixed Closed and Open Inter-Depot Routes and is, in this paper, modeled through a mixed integer linear programming (MILP) formulation where capacity and duration constraints are taken into account. The model developed is applied to the real case study providing, as final results, the vehicle routes planning where a decrease of 13% on mileage and 11% on fleet hiring cost are achieved, when comparing with the current company solution. 相似文献
116.
沉积物毒性鉴别评估用于确定造成沉积物整体毒性测试中观察到有害效果的原因。然而在多污染物的情况下,将总体毒性划分为为不同个体污染物单独造成的毒性的方法存在很多问题。利用一个有着多重输入与相关污染物的站点数据,我们为毒性鉴别评估提出一种通过追踪毒性单位(TUs)来确定是否囊括全部毒性的方法。首先确定出沉积物整体的毒性水平,然后将毒性来源划分至几种污染物大类,例如氨类,金属,非极性有机物等。本文中毒性很大程度上来源于非极性有机物,所以在萃取沉积物之后,将萃取物重新加回稀释水中以检测毒性的复原。每一部分污染物的毒性占比由溶剂梯度测量,并进行毒性检测。目标占比由气相色谱-质谱分析得到,从而鉴定出与特定成分相关的毒性。之后对这些成分相关的毒性单位进行测定以确定可能的原因组合和是否已囊括全部毒性。数据表明毒性既与已有化合物相关,又与新兴污染物相关,而两种污染物对于总体毒性的具体贡献则随实验地点改变。
精选自Howard C. Bailey, Catherine A. Curran, Peter Arth, Bonnie P. Lo, Rich Gossett. Application of Sediment Toxicity Identification Evaluation Techniques to a Site with Multiple-Contaminants. Environmental Toxicology and Chemistry: Volume 35, Issue 10, pages 2456–2465, October 2016.
DOI: 10.1002/etc.3488
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3488/full 相似文献
117.
Multiple sulphatase deficiency was diagnosed in the first trimester of pregnancy by demonstrating markedly reduced activities of arylsulphatases and heparin sulphamidase by direct assays on chorionic villi (CV). The diagnosis was confirmed by assays on cell cultures of villi and fetal skin fibroblasts. Two further pregnancies of this mother were monitored similarly and predicted to be unaffected; one produced a normal healthy infant, the other miscarried shortly after CV sampling. 相似文献
118.
介质层振动信号时域分析及其在填埋场漏洞修 总被引:1,自引:0,他引:1
钻探灌浆修补技术是填埋场防渗层漏洞修补的重要发展方向,难点是如何准确地控制和判断钻头到达填埋场防渗层(即卵石保护层)而不会破坏其下面的HDPE膜. 利用采集仪对钻头在防渗层不同介质层中的振动加速度信号进行采集,分别采用波形幅度分析法、循环绝对值求和法及分段均方根法对数据进行了分析. 结果表明:①波形幅度分析法能够明显区分垃圾层和卵石层;②循环绝对值求和法与分段均方根法也可区分垃圾层和卵石层,但存在约1 s的时间误差或0.5 cm的距离误差,该误差在允许的范围内. 3种不同时域分析方法的对比显示,波形幅度分析法简单直观,其他2种分析方法能够直观地反映信号的包络趋势,据此敏感地反映信号的突变情况和加速度幅度大小在单位时间内的概率分布,进而可以灵活地控制钻机. 相似文献
119.
Jean-Pierre Arz Jean-Pierre Gettliffe Philippe Delattre 《International journal of occupational safety and ergonomics》2018,24(1):149-159
The effect of wearing hearing protectors on the audibility of warning signals has been evaluated for three specific railway-related jobs: track workers, train drivers and platform agents. Masked thresholds were measured in the laboratory, on railway agents with normal hearing, using warning signals and background noises typical of each job. Out of the 36 situations tested in total, statistical analyses showed that wearing earplugs improves the perception in 11 situations, deteriorates the perception in 10 situations and has no significant effect in 15 situations (as compared to no hearing protector). The deteriorations essentially concern signals which have no (or not enough) energy in the low-frequency range (f1500?Hz) when they have to be heard in background noises which dominate in the low-frequency range. To prevent the deteriorations, these signals could be modified by adding some energy in the low-frequency range (f1500?Hz). 相似文献
120.
为探究组合煤岩力学性质与声-电荷信号关系,选用新邱矿区煤样和砂岩制备组合煤岩试样,采用物理实验和数值实验相结合的方法,开展不同岩煤高度比的组合煤岩试样受载破坏声发射与电荷感应监测试验,得到了组合煤岩力学性质、声-电荷信号规律及其相互关系。结果表明:组合煤岩试样中的岩石高度提高会提升其整体强度,其破坏脆性特征显著,冲击倾向性增强,弹性阶段的声发射信号提前,声发射能量累积量增加,峰后声发射能量变化率及电荷变化率增大;组合煤岩峰后产生连续声发射信号和电荷信号,强冲击和中等冲击组合煤岩破坏时声发射能量变化率分别为0.336和0.047 J/s,电荷变化率分别为204.88和24.52 pC/s。声发射信号与电荷信号可以在一定程度上反应组合煤岩应力状态并预测失稳破坏,为通过信号监测煤体冲击地压灾害发生提供依据。 相似文献