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731.
An Operational Model for Implementing Conservation Action 总被引:10,自引:0,他引:10
732.
Lizards and birds are both popular ”model organisms” in behavioural ecology, but the interactions between them have attracted
little study. Given the putative importance of birds as predators of diurnal lizards, it is of considerable interest to know
which traits (of lizards as well as birds) influence the outcome of a predatory attempt. We studied predation by giant terrestrial
kingfishers (kookaburras, Dacelo novaeguineae: Alcedinidae) on heliothermic diurnal lizards (highland water skinks, Eulamprus tympanum: Scincidae), with particular reference to the role of prey (lizard) size. Our approach was twofold: to gather direct evidence
(sizes of lizards consumed in the field, compared to those available) and indirect evidence (size-related shifts in lizard
behaviour). We quantified the size structure of a natural population of skinks (determined by an extensive mark-recapture
program), and compared it to the sizes of wild lizards taken by kookaburras (determined by analysis of prey remains left at
the birds’ nests). Kookaburras showed size-based predation: they preyed mainly on small and medium-sized rather than large
lizards in the field. However, the mechanism producing this bias remains elusive. It is not due to any distinctive behavioural
attributes (locomotor ability, activity level, habitat usage) of the lizards of the size class disproportionately taken by
the kookaburras. The greater vulnerability of subadult lizards may reflect subtle ontogenetic shifts in ecological and behavioural
traits, but our data suggest that great caution is needed in inferring patterns of vulnerability to predation from indirect
measures based on either the prey or the predator alone. Instead, we need direct observations on the interaction between the
two.
Received: 30 May 2000 / Revised: 29 July 2000 / Accepted: 26 August 2000 相似文献
733.
Thomas Baldwin 《黑龙江环境通报》2006,26(7):637-645
Current debates about sex selection start from a paradox: on the one hand, the ‘liberal’ argument in favour of sex selection is often thought to be sound; but on the other hand there is widespread public opposition to sex selection. So it is worth spending some time examining the arguments against sex selection. Four different types of argument are identified: (i) religious arguments; (ii) consequentialist arguments, mainly concerning disturbance to the sex ratio; (iii) arguments to the effect that sex selection involves a failure to respect the autonomy of a child; (iv) arguments to the effect that the motivation for sex selection brings with it an instrumental attitude to children not compatible with a child's need for unconditional acceptance and love. In the end the conclusion is reached that none of these arguments provide decisive arguments against the liberal thesis that sex selection ought to be permitted, especially where 'family balancing' is envisaged. In the light of this conclusion the issue of fetal sexing followed by selective feticide as a method of sex selection is discussed. It is argued that sex selection is not in general a good reason for abortion, but that this practice may become unstoppable. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
734.
A group of sympatric aquatic and semiaquatic spiders inhabiting Western Siberia (Argyroneta, Dolomedes, Pirata, and Pardosa) has been studied with respect to specific ethological features. The results provide a basis for the conclusion that these spiders differ in a number of behavioral adaptations related to prey catching and the use of common biotopic space. Experiments with the predator–prey system have shown that spiders have different effects on the abundance of bloodsucking mosquito larvae and on the age and genetic structure (at the chromosomal level) of their populations. The functional role of spiders in communities is discussed. 相似文献
735.
新的国际标准要求对安全监控系统进行安全整体水平评价。通过对适用评价方法的比较和分析,认为扩展的马尔克夫分析方法具有系统评价完整,适用性强的明显优点。 相似文献
736.
737.
基于物种敏感性分布法的生态风险评价研究进展 总被引:4,自引:0,他引:4
生态风险评价是认识生态健康和污染物可能对生态环境产生不良影响的重要手段,而物种敏感性分布法是使用较为广泛的评价方法,其核心步骤是筛选出合适物种的毒性数据进行曲线拟合。在简要介绍物种敏感性分布法原理和步骤的基础上,综述了物种敏感性分布法应用的几个关键问题,即物种筛选、毒性数据选择和拟合模型确定。针对特殊水体,提出了基于区域同类型水环境物种对比的物种筛选法和基于水环境历史物种比较的物种筛选法。最后对未来的研究工作进行了展望,指出现有研究的不足和未来研究的方向。 相似文献
738.
739.
740.
随着经济的发展,建设项目选址不合理导致的大气环境问题日益凸显。文章分析了建设项目选址的大气环境适宜性问题,提出了大气环境适宜性的计算方法,并以济南市某建设项目为例进行了具体应用。该研究可用于修正历史上形成的项目不合理选址,也可用于引导新建项目合理选址,利于大气环境持续利用和经济持续发展。 相似文献