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51.
52.
Krista Ryall Peter J. Silk Junping Wu Peter Mayo Matthew A. Lemay David MaGee 《Die Naturwissenschaften》2010,97(8):717-724
The elm spanworm, Ennomos subsignaria (Hübner), occurs throughout Canada and the eastern United States and can be a destructive forest pest on a wide range of
deciduous trees. Gas chromatography/mass spectrometry (GC/MS) and coupled gas chromatographic–electroantennographic detection
(GC/EAD) analysis of pheromone gland extracts, in combination with chemical synthesis and field trapping studies have identified
(2S, 3R)-2-((Z)-oct-2′-enyl)-3-nonyl oxirane (hereafter Z6-9S, 10R-epoxy-19:H) as the female-produced sex pheromone. Significantly more male moths were captured between 1–100 μg loadings of
this compound on red rubber septa in sticky traps compared to blank (unbaited) traps; catches then declined at higher dosages
(500–1000 μg). The other isomeric enantiomer, (2R, 3S)-2-[(Z)-oct-2′-enyl]-3-nonyl oxirane (Z6-9R, 10S-epoxy-19:H), at a 10-μg dosage did not elicit trap capture. The likely precursor to the active epoxide, (Z, Z)-6, 9-nonadecadiene ((Z, Z)-6, 9-19:H), identified in virgin female sex pheromone glands, did not elicit trap capture either, and inhibited trap capture
when combined with the active epoxide. Racemic 2-((Z)-oct-2′-enyl)-3-nonyl oxirane showed no significant difference in trap
capture compared with Z6-9S, 10R-epoxy-19:H, indicating that the opposite enantiomer was not antagonistic. The addition of the EAD-active diene epoxide enantiomers
(2S, 3R)-2-[(Z, Z)-octa-2′, 5′-dienyl]-3-nonyl oxirane or (2R, 3S)-2-[(Z, Z)-octa-2′, 5′-dienyl]-3-nonyl oxirane in admixture with Z6-9S, 10R-epoxy-19:H (at 10% of the latter) did not enhance or decrease trap capture compared to Z6-9S, 10R-epoxy-19:H oxirane alone, so they are not likely pheromone components. This pheromone, impregnated in rubber septa at less
than 100-μg dosage, can now be used as a trap bait to develop detection and monitoring strategies for this insect. 相似文献
53.
The acute toxicity of monodispersed 6 nm and <100 nm poly-dispersed copper oxide nanoparticles toward Daphnia magna was assessed using 48 h immobilization tests. CuSO4 was used as a reference. Four different exposure conditions were tested, to study whether the toxicity of the nanoparticle suspensions changed in a way similar to what is known for dissolved Cu: first in ISO standard test conditions (pH 7.8), second with slight acidity (pH 6.5), third in the presence of citric acid, and fourth in the presence of humic acid. For all four exposure conditions, the toxicity of Cu employed in the three forms followed the same sequence, i.e., CuSO4 > monodispersed 6 nm CuO ? poly-dispersed CuO. The toxicity of all Cu forms decreased from pH 6.5, ? pH 7.8, > pH 7.8 + citric acid, to ? pH 7.8 + humic acid. This pattern is in agreement with concentrations of Cu2+ calculated using the equilibrium model MINTEQ. These findings show that the acute toxicity of copper oxide nanoparticles is governed by test water composition and the chemical species Cu2+. 相似文献
54.
Mark Weinblatt M.D. Boris Petrikovsky Martin Bialer Joseph Kochen Rita Harper 《黑龙江环境通报》1994,14(9):892-896
A fetus with absent radii in both forearms was discovered on routine ultrasound examination performed at 18 weeks of pregnancy. No other significant abnormalities were found, and no signs of haemorrhage were detected. Serial ultrasound examinations revealed no evidence of fetal internal bleeding. At 37 weeks of pregnancy, a CBC obtained by cordocentesis under ultrasound guidance confirmed the diagnosis of thrombocytopenia absent radii (TAR) syndrome. Apheresis platelets were transfused into the umbilical vein to correct the thrombocytopenia and was followed by an uncomplicated delivery. No bleeding was encountered during the remainder of the baby's neonatal course. We conclude that TAR syndrome can be readily identified prenatally on sonogram, and if severe thrombocytopenia is confirmed by cordocentesis, platelets should be transfused to diminish the risk of serious internal bleeding during and immediately after delivery. 相似文献
55.
Meena Upadhyaya Bharat Jasani Elizabeth Little Peter S. Harper Derek Rees Adrian Roberts 《黑龙江环境通报》1987,7(2):119-127
A study of villus samples from eight random sites on five electively aborted chorion sacs was performed to determine any significant differences in yield, quality and composition of DNA, iduronate sulphate sulphatase activity and karyoptype status. The villi were also examined for their histological characteristics (e.g. stem, intermediate or terminal villi) and for HCG and BGP immuno-reactivities. The overall findings indicated no significant site to site variations in any of the parameters studied. It is therefore proposed that any villus should be equally suitable for prenatal diagnosis. 相似文献
56.
Developing Peak Discharges for Future Flood Risk Studies Using IPCC's CMIP5 Climate Model Results and USGS WREG Program 下载免费PDF全文
Sivasankkar Selvanathan Mathini Sreetharan Krista Rand Dmitry Smirnov Janghwoan Choi Mathew Mampara 《Journal of the American Water Resources Association》2016,52(4):979-992
Extreme climate events, floods, and drought, cause huge impact on daily lives. In order to produce society resilient to extreme events, it is necessary to assess the impact of frequent and high intensity storm events on design parameters. This article describes a methodology to develop future peak “design discharges” throughout the United States that can be used as a guidance to map future floodplains. In order to develop a lower and upper limit for anticipated peak flow discharges, two future growth scenarios — Representative Concentration Pathways (RCPs)‐RCP 2.6 and 8.5 were identified as the weak and strong climate scenario respectively based on the output from the global climate models. The Generalized Least Square technique in United States Geological Survey's Weighted Multiple Regression (WREG) program was used to develop regression equations that relate peak discharges to basin and climate parameters of the contributing watershed. The design discharges reflect the most recent climate model results. Number of frost days, heavy rainfall days, high temperature days, and snow depth were found to be the common extreme climate parameters influencing the regression equations. This methodology can be extended to other flood frequency events if rainfall data is available. The future discharges can be utilized in hydraulics models to estimate floodplains that can assist in resilient infrastructure planning and outline climate change adaptation strategies. 相似文献
57.
58.
Henk W.M. Witlox Mike Harper Adeyemi Oke 《Journal of Loss Prevention in the Process Industries》2009,22(6):795-802
This paper discusses the modelling of the discharge and subsequent atmospheric dispersion for carbon dioxide releases using extensions of models in the consequence modelling package Phast. Phast examines the progress of a potential incident from the initial release to the far-field dispersion including the modelling of rainout and subsequent vaporisation. The original Phast discharge and dispersion models allow the released chemical to occur only in the vapour and liquid phases. As part of the current work these models have been extended to also allow for the occurrence of liquid to solid transition or vapour to solid transition. This applies both for the post-expansion state in the discharge model, as well as for the thermodynamic calculations by the dispersion model. Solid property calculations have been added where necessary. The above extensions are generally valid for fluid releases including CO2. Using the extended dispersion formulation, a sensitivity study has been carried out for mixing of solid CO2 with air, and it is demonstrated that solid effects may significantly affect the predicted concentrations. 相似文献
59.
Krista M.S. Kemppinen Pamela M. Collins David G. Hole Christopher Wolf William J. Ripple Leah R. Gerber 《Conservation biology》2020,34(5):1221-1228
The loss of forest is a leading cause of species extinction, and reforestation is 1 of 2 established interventions for reversing this loss. However, the role of reforestation for biodiversity conservation remains debated, and lacking is an assessment of the potential contribution that reforestation could make to biodiversity conservation globally. We conducted a spatial analysis of overlap between 1,550 forest-obligate threatened species’ ranges and land that could be reforested after accounting for socioeconomic and ecological constraints. Reforestation on at least 43% (∼369 million ha) of reforestable area was predicted to potentially benefit threatened vertebrates. This is approximately 15% of the total area where threatened vertebrates occur. The greatest opportunities for conserving threatened vertebrate species are in the tropics, particularly Brazil and Indonesia. Although reforestation is not a substitute for forest conservation, and most of the area containing threatened vertebrates remains forested, our results highlight the need for global conservation strategies to recognize the potentially significant contribution that reforestation could make to biodiversity conservation. If implemented, reforestation of ∼369 million ha would also contribute substantially to climate-change mitigation, offering a way to achieve multiple sustainability commitments at once. Countries must now work to overcome key barriers (e.g., unclear revenue streams, high transaction costs) to investment in reforestation. 相似文献
60.
Bettinetti R Quadroni S Crosa G Harper D Dickie J Kyalo M Mavuti K Galassi S 《Ambio》2011,40(4):341-350
Dichlorodiphenyltrichloroethane (DDT) is still used in Africa for the indoor control of malaria and it may represent a potential
hazard for wildlife. The littoral sediments of two alkaline-saline lakes, Natron (Tanzania) and Bogoria (Kenya), in the Eastern
Rift Valley, supporting large populations of lesser flamingos (Phoeniconaias minor), were analysed for DDT residues. Physical–chemical analyses (temperature, conductivity, pH and dissolved oxygen) were also
performed on the water of the two lakes and in the tributaries of Lake Natron, to evaluate the influence of the environmental
variables on pollutant occurrence. At Lake Natron, around 1 km from the sediment collection sites, tree leaves of Acacia tortilis were also collected. The main metabolite found in all sediment samples was pp’DDE, whilst equal concentrations of pp’DDT
and pp’DDE were measured in acacia leaves. The levels of DDTs measured in the sediments were within 5.9–30.9 ng g−1 d.w., reaching the maximum value in a tributary of Lake Natron. On the whole, the contamination of Lake Natron and Lake Bogoria
basins seems to be quite moderate. Nevertheless, the pp’DDE/pp’DDT ratio equals 1 in the Acacia tortilis leaves, which makes one suppose that the input of the parent compound was rather recent and could have been from aerial transport
or dust from relatively close-by old pesticides storage sites. 相似文献