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31.
Robert M. Gibson 《Behavioral ecology and sociobiology》1996,39(1):55-59
Previous studies of female choice in sage grouse Centrocercus urophasianus have implicated both the acoustic quality and repetition rate of the stereotyped strut display as putative cues for female
choice. Stages in the choice process at which specific components of male courtship display influence female decisions were
investigated using field observations of female pre-mating behavior. Females visited a subset of territorial males and then
actively chose one of these as a mate. The order in which males were visited suggested that females searched until an acceptable
mate was found, rather than employing a “best-of-n” tactic. Numbers of females visiting a male were related to differences
in an acoustical component of display (inter-pop interval) whereas the probability that a visiting female mated was related
to display rate (Table 3), indicating that initial attraction and active choice are influenced by different components of
display. In addition, inter-pop interval and display rate tended to covary inversely (Fig. 1), suggesting that attraction
and active choice may impose conflicting selection pressures on display performance.
Received: 11 November 1995/Accepted after revision: 16 March 1996 相似文献
32.
33.
Paul J. Weldon 《Chemoecology》2004,14(1):1-4
Summary. Many animals acquire substances on their integument from heterospecifics
through anointing. In active or self-anointing, animals rub against scent
sources or they apply them by appendage or mouth. In passive anointing, animals
adsorb emitted chemicals. Most investigators suggest that chemicals appropriated
via anointing deter predators, ectoparasites, and/or microbial pathogens. Similarly,
nesting birds and brood parasites of social insects acquire chemicals from and reside
unmolested near or within insect colonies. The acquisition through anointing of
chemicals that deter predators, ectoparasites, microbial pathogens, and other
offenders, i.e. defensive anointing, constitutes an extended phenotype: the
genetic machinery by which defensive compounds are synthesized does not reside with
the anointing organisms, but the sensory mechanisms and/or behavioral tendencies by
which chemicals are appropriated from heterospecifics do. The ecological
relationships between anointing organisms and chemical donors, and between
chemical donors and those responding to chemicals appropriated via anointing, may
be unorthodox. Interactions between anointing organisms and chemical donors typically
entail abrasive contact with or other damage to the latter. These encounters sometimes
are evidenced by telltale marks on chemical donors or by chemicals deposited on the
integument of anointing organisms. The organisms furnishing chemicals and those
affected by them may not interact, and they may even occupy different habitats, because
mobile anointing organisms are the medium by which chemicals are disseminated. Thus,
in allelochemical studies where anointing is involved, species can be tested, with
ecological legitimacy, using chemicals from organisms they might fail to interact with
in nature. Practical implications of anointing stem from its potential importance in
conservation and captive management, where consideration is given to the protection
that animals derive by accessing topically acquired chemicals from heterospecifics. 相似文献
34.
M. Turk J. Jakšić M. Vojinović Miloradov J. Klanova 《Environmental Chemistry Letters》2007,5(3):109-113
For the duration of the war accident in former Yugoslavia, several industrial and military targets were burnt and damaged,
resulting in a significant release of persistent organic pollutants. Locations heavily targeted in the attacks were later
defined by UNEP as four “hot spots”: Kragujevac, Novi Sad, Pancevo and Bor. We analyzed concentration levels of pollutants
collected in 2004 and 2005 in air samples from the city of Kragujevac, Serbia, following the war accident of 1999. Pollutants
included polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexane (HCH), dichloro-diphenyl-trichloroethane (DDT), dichloro-diphenyl-dichloroethylene
(DDE), dichloro-diphenyl-dichloroethane (DDD) and polychlorinated biphenyls (PCBs). We present results obtained during air
sampling campaign conducted in July 2004 by the active sampling method; and during September 2004–June 2005 by the passive
sampling method. Our findings show the occurrence of residual quantities of DDT, HCH, PCBs and PAHs in air samples. High levels
of PCBs are probably due to the destruction of transformers during the war accident. 相似文献
35.
罗新华 《石油化工环境保护》1998,(2):26-30
活性污泥法完全混和式和阶段曝气组合工艺,具有抗冲击能力强,有机物去除率高等特点。该工艺组合中微生物经常受到的冲击有进水COD、BOD、碱度和曝气池低溶解氧。所采取的措施分别有:终水回流稀释、PH值控制、营养盐浓度控制、原水预曝气等。 相似文献
36.
湿地土壤有机碳及其活性组分分布特征影响因素研究 总被引:1,自引:0,他引:1
红碱淖湖泊湿地是西北半干旱荒漠区重要的生态屏障,随着湖泊面积的减少以及土壤退化程度的加剧,逐渐形成5种典型的景观类型(盐碱沼泽、沼泽化草甸、草地、草原化沙地、沙地)。基于野外实地调查,选取红碱淖湖泊湿地流域蟒盖兔和尔林兔2个典型子流域,研究湖泊退化后不同景观类型土壤有机碳及其活性组分的分布特征及其影响因素。结果表明,5种景观类型土壤有机碳(SOC)、土壤可溶性有机碳(DOC)、土壤易氧化态有机碳(EOC)含量均较低。土壤SOC和EOC在垂直剖面上分布特征一致,土壤EOC与土壤有机质动态变化密切相关,土壤砂砾含量高是研究区土壤有机碳含量较低的主要原因。 相似文献
37.
Soil organic carbon decomposition and carbon pools in temperate and sub-tropical forests in China 总被引:2,自引:0,他引:2
Yang L Pan J Shao Y Chen JM Ju WM Shi X Yuan S 《Journal of environmental management》2007,85(3):690-695
Decomposition of soil organic carbon (SOC) is a critical component of the global carbon cycle, and accurate estimates of SOC decomposition are important for forest carbon modeling and ultimately for decision making relative to carbon sequestration and mitigation of global climate change. We determined the major pools of SOC in four sites representing major forest types in China: temperate forests at Changbai Mountain (CBM) and Qilian Mountain (QLM), and sub-tropical forests at Yujiang (YJ) and Liping (LP) counties. A 90-day laboratory incubation was conducted to measure CO(2) evolution from forest soils from each site, and data from the incubation study were fitted to a three-pool first-order model that separated mineralizable soil organic carbon into active (C(a)), slow (C(s)) and resistant (C(r)) carbon pools. Results indicate that: (1) the rate of SOC decomposition in the sub-tropical zone was faster than that in the temperature zone, (2) The C(a) pool comprised approximately 1-3% of SOC with an average mean residence time (MRT) of 219 days. The C(s) pool comprised approximately 25-65% with an average MRT of 78 yr. The C(r) pool accounted for approximately 35-80% of SOC, (3) The YJ site in the sub-tropical zone had the greatest C(a) pool and the lowest MRT, while the QLM in the temperature zone had the greatest MRT for both the C(a) and C(s) pools. The results suggest a higher capacity for long-term C sequestration as SOC in temperature forests than in sub-tropical forests. 相似文献
38.
当前防火墙的防御策略为被动防御 ,它只能被动等待攻击者的攻击 ,直接降低了其安全性能。从安全心理学的角度出发 ,分析了被动式防火墙的弱点并设计了一种新型防火墙。该防火墙采用主动式防御策略 ,对于在防火墙中识别出的非法访问 ,通过重定向 ,引导至识别区来保护主系统 ,降低攻击者的攻击欲望 ,从而提高了防火墙的安全性能。防火墙中关键技术为攻击识别技术和重定向技术。 相似文献
39.
S. Giordano P. Adamo E. Pittao R. Bargagli 《Environmental pollution (Barking, Essex : 1987)》2009,157(10):2798-2805
To define a harmonized methodology for the use of moss and lichen bags as active monitoring devices of airborne trace elements in urban areas, we evaluated the element accumulation in bags exposed in Naples in different spring weather conditions for 6- and 12-weeks. Three different pre-exposure treatments were applied to moss and lichen materials: water-washing, acid-washing and oven-drying. During the different exposure periods in the Naples urban environment the moss accumulated always higher amounts of elements (except Hg) than lichens and the element accumulation increased during wetter weather and higher PM10 conditions. The oven pre-treatment did not substantially modify the morphology and element composition of moss and the exposure in bags of this material for 6-weeks was sufficient to detect the pattern of airborne trace elements. 相似文献
40.
磁化处理对活性污泥胶体颗粒表面的zeta电位的影响 总被引:1,自引:0,他引:1
污水处理过程中,二沉池的泥水分离影响整套工艺的效果,用投加混凝剂来降低活性污泥胶体颗粒表面的zeta电位(以下简写活性污泥zeta电位),增加了运行成本.通过磁场磁化可以降低活性污泥zeta电位,达到节省药剂的目的.研究了磁感应强度、磁化时间、磁场位型以及搅拌速率对氧化沟活性污泥zeta电位的影响规律.研究表明,磁化处理能降低活性污泥zeta电位,在磁场中心磁感应强度为0.40 T左右及反应器与磁场平行静置磁化时,zeta电位降低幅度最大,平均在46.5%~51.4%. 相似文献