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71.
Konstantinos G. Maragkos John N. Hahladakis Evangelos Gidarakos 《Waste management (New York, N.Y.)》2013,33(9):1882-1889
Twenty four waste cellular phones, manufactured between 2002 and 2011, were selected in order to determine the total heavy metal content in each of their parts (printed circuit boards (PCBs), plastic housing (PH) and liquid crystal display monitors (LCDs)) and compare the results with the permissible limits set by the 2003 Directive on Restriction of Hazardous Substances (RoHS). All the selected samples were pulverized and digested with strong acids. Inductively coupled plasma-mass spectrometry was used to measure the heavy metal content in each sample. The results revealed that concentration levels of the examined heavy metals were higher in PCBs, followed by PH and LCD in that particular order (PCB > PH > LCD). With the exception of Pb and Cr present in PCBs of mobile phones released before the year 2006, all the other metal concentrations were according to the Directive. Concentration levels of Cd, Hg were lower than the permissible limits set by the EU, either before or after the validity of the 2003 RoHS Directive. Considering their significant heavy metal content, coupled with their large quantities produced worldwide in an annual rate, waste cellular phones need to be treated under an environmentally sound management scheme, prioritizing recycling and at the same time eliminating the possibility of any harm. 相似文献
72.
Indrikis Krams Tatjana Krama Kristine Igaune Raivo Mänd 《Behavioral ecology and sociobiology》2008,62(4):599-605
Although human behaviour abounds with reciprocal altruism, few examples exist documenting reciprocal altruism in animals.
Recent non-experimental evidence suggests that reciprocal altruism may be more common in nature than previously documented.
Here we present experimental evidence of mobbing behaviour, the joint assault on a predator in an attempt to drive it away,
as reciprocal altruism in the breeding pied flycatcher (Ficedula hypoleuca). Given a choice, pied flycatchers assisted in mobbing initiated by co-operating neighbours and did not join in mobbing when
initiated by conspecific neighbours which had defected from necessary assistance 1 h before. The results suggest the birds
followed a ‘tit-for-tat’-like strategy and that mobbing behaviour of breeding birds may be explained in terms of reciprocal
altruism. 相似文献
73.
74.
Collective detection concerns the idea that all members of a socially feeding group are alerted to an attack as long as at
least one group member detects it. We found that collective detection in mixed flocks of emberizid sparrows is limited markedly
by relatively small degrees of visual and spatial separation between foragers. These limits on collective detection appear
to influence the degree to which flock members lower their vigilance with increasing group size (the group size effect). Specifically,
the decrease in collective detection with increasing visual and spatial isolation between foragers is accompanied by a concomitant
decrease in the strength of the vigilance group size effect. Explanations for the vigilance-related effects of such separation
based upon a bird’s ability to monitor the vigilance behavior of flockmates can be ruled out for our experimental system.
Our results also shed light on the issue of whether the vigilance group size effect is influenced more by collective detection
or the simple dilution of risk with increasing group size. We argue that collective detection is not only an important determinant
of the group size effect, but also that the phenomena of collective detection and risk dilution are interdependent.
Received: 25 July 1995/Accepted after revision: 17 December 1995 相似文献
75.
76.
Peter H. Kahn Jr. Batya Friedman Brian Gill Jennifer Hagman Rachel L. Severson Nathan G. Freier Erika N. Feldman Sybil Carrre Anna Stolyar 《Journal of environmental psychology》2008,28(2):192-199
Humans will continue to adapt to an increasingly technological world. But are there costs to such adaptations in terms of human well being? Toward broaching this question, we investigated physiological effects of experiencing a HDTV quality real-time view of nature through a plasma display “window.” In an office setting, 90 participants (30 per group) were exposed either to (a) a glass window that afforded a view of a nature scene, (b) a plasma window that afforded a real-time HDTV view of essentially the same scene, or (c) a blank wall. Results showed that in terms of heart rate recovery from low-level stress the glass window was more restorative than a blank wall; in turn, a plasma window was no more restorative than a blank wall. Moreover, when participants spent more time looking at the glass window, their heart rate tended to decrease more rapidly; that was not the case with the plasma window. Discussion focuses on how the purported benefits of viewing nature may be attenuated by a digital medium. 相似文献
77.
为了降低胎压监测系统的功耗和优化胎压监测系统的显示方式,设计了一种基于SP12传感器的安全胎压监测系统方案。从硬件和软件两方面描述了系统的设计实现方法。在硬件设计上,采用车载电源和充电电池两种方式对主机进行供电,同时,系统应用SP12多功能传感器降低功耗。在软件设计上,着重介绍了轮胎采集模块和中央显示模块的设计。为进一步优化系统的显示方式,中央显示模块采用带触摸屏的LCD显示器作为人机交互接口。实际测试结果表明,该系统可实时监测每个轮胎内部的实际温度、压力和电压,确定故障轮胎并实时报警,有效避免爆胎事故的发生。另外,系统在安全性、低功耗以及可靠性方面具有一定的优势,这也符合智能车辆研究的发展趋势。 相似文献
78.
硫磺对礼花弹的成型、开盘面积的安全性具有重要影响。采用调整硫磺在礼花弹开球药中的比例,以及分析硫磺的物理化学性能来探讨硫磺在整个开球药中的作用机理。实验结果表明,硫磺在开球药中起着特殊"热点"的作用,作用机理主要是表面反应机理与混合反应机理的共同作用。当硫磺比例在15%-20%的安全用量范围内时,随着硫磺的增多开球药特殊"热点"不断增多,此时开球后花形更加趋于球形,开盘面积也足够大。 相似文献
79.
80.
废手机面板焚烧产物研究 总被引:1,自引:1,他引:0
以废手机面板为试验材料,利用热重分析仪(TGA)研究热处理失重特征,同时利用气相色谱仪-质谱仪联用(GC-MS)对管式炉试验系统焚烧产物进行分析. 结果表明:废手机面板焚烧失重温度为128.3~558.1 ℃,最大失重温度为357.4 ℃;焚烧废手机面板导致面板组成材料液晶、偏光片和取向剂等发生化学反应,焚烧产物除CO2外,还含有醛、酮、联苯酚、苯胺等芳香族化合物和少量的苯并吡喃、萘、菲、吡啶等多环芳烃(PAHs). 由于焚烧产物中绝大多数是有毒有害物质,部分可致癌,故废手机面板不宜焚烧处理,如与其他固体废物混合焚烧,必须采取相应的污染控制措施. 相似文献