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131.
Atmospheric deposition of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in urban and suburban areas of Korea 总被引:1,自引:0,他引:1
Bulk atmospheric samples (wet and dry) were collected monthly throughout a year at urban and suburban areas of Korea to assess the deposition flux and seasonal variations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The PCDDs/DFs deposition fluxes ranged from 1.0 to 3.7 ng TEQ/m2/year in the urban area and from 0.5 to 4.6 ng TEQ/m2/year in the suburban area. The deposition fluxes of PCDDs/DFs in this study were comparable to or lower than those previously reported at different locations. The atmospheric deposition fluxes of particles and PCDDs/DFs in winter tended to be higher than those in summer. However, monthly variations between particle and PCDDs/DFs deposition fluxes were small, and the correlation coefficients between the deposition fluxes of air particles and each homologue group of PCDDs/DFs varied according to the degree of chlorination of the homologue group. The deposition velocity of PCDDs/DFs in the urban area was estimated at 0.04 cm/s, which is a lower value than those found in other studies. The two most likely factors affecting the monthly variation of deposition fluxes are the ambient temperature and the amount of precipitation. In particular, the ambient temperature had an influence on the lower chlorinated homologues of PCDDs/DFs while precipitation had an influence on the higher chlorinated PCDDs/DFs. The PCDDs/DFs profiles in atmospheric deposition bulk samples showed a similar pattern at the urban and suburban sites. The possibility of the loading of PCDDs/DFs by Asian dust events could be partly confirmed by investigation of homologue profiles. 相似文献
132.
Nobuo Sugimoto Atsushi Shimizu Ichiro Matsui Itsushi Uno Kimio Arao Xuhui Dong Shuli Zhao Jun Zhou Choo-Hie Lee 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):145-157
We have conducted dust observations at a number of locations including Beijing, Hefei, Suwon, Fukue, Nagasaki, Tsukuba, and
Sapporo using automated two-wavelength polarization lidars o study Asian dust phenomena, including generation, transport,
and change during transport. We developed a method using the depolarization ratio for estimating the contributions of Asian
dust and spherical air-pollution aerosols in observed aerosol mixtures. We analyzed the dust profiles statistically to derive
climatological characteristics and year-on-year variations. We also studied dust source and transport path for each dust event
using the regional chemical transport model CFORS. The statistical analysis clearly demonstrated the year-on-year variation
of dust phenomena and the characteristics depending on the locations of the observational sites. Most major dust events in
2001 and 2002 originated in Inner Mongolia and/or Mongolia at the southern edge of a low-pressure area located in Siberia
and were transported by strong westerlies. In 2003, the typical meteorological pattern for heavy dust cases accompanying a
strong low in Siberia was not seen, except for one case in April. Furthermore, the lidar observation in Beijing suggests that
less dust was generated in the source regions in Inner Mongolia and/or Mongolia, probably due to higher precipitation in 2003. 相似文献
133.
Yasuhito Igarashi Michio Aoyama Katsumi Hirose Pavel Povinec Sadayo Yabuki 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):51-69
Currently, atmospheric anthropogenic radionuclides (particulate) are controlled by suspension of the surface dust containing
those radionuclides (resuspension). We have found, therefore, that such radionuclides can be used as tracers of the surface
dust suspension, transport and its subsequent deposition in distant areas. The 137Cs/90Sr activity ratios in the atmospheric deposition, without the direct influence of nuclear tests and accidents, at the Meteorological
Research Institute (MRI, Tsukuba, Japan) during the 1990s were fairly low (average: 2.1). This value is not in agreement with
the ratios in Japanese surface soils (range of averages: 4–7), which had been considered as the primary source of the deposited
dust. This suggests that the current atmospheric dust deposition in Japan is a mixture of local and remote components. The
remote component could be an aeolian dust that has been transported long distances from arid areas. The major component is
most likely to be Asian dust. It was further hypothesized that other remote source may exist beyond the Asian domain, based
on accumulated observations and model results. To obtain more information about the dust transport, Sahara dust deposited
in Monaco in 2002 and a suspended dust collected in the Taklamakan area in 2001 were analyzed for 90Sr and 137Cs. The Taklamakan dust exhibited a 137Cs/90Sr ratio of about 4, which is within the range of atmospheric deposition observed at the MRI, while the Sahara dust exhibited
a higher 137Cs/90Sr ratio (about 13). Although the present Sahara datum was negative for our hypothesis of ‘hyper-range transport’, the seasonal
change of the 137Cs/90Sr ratio in the atmospheric deposition observed at the MRI requires an aeolian dust source having a low 137Cs/90Sr ratio, other than Asian dust. 相似文献
134.
David E Fritz 《Spill Science & Technology Bulletin》2003,8(4):331-335
In situ burning is being utilized in the United States to remove oil from inland oil spills, usually when physical recovery is not feasible. Studies have found that habitats may recover from the effects of burning in less than a year under optimal conditions but recovery may take much longer. Policies authorizing the use of in situ burning across the US are very inconsistent. Some states use it routinely, but others do not allow it. Inland in situ burning can be a useful response tool and the federal government needs to issue more guidance to the states. Responders also need to collect more data on the environmental impacts of burning. 相似文献
135.
The giant Asian honeybee (Apis dorsata), like all other members of the genus Apis, has a complex mating system in which the queens and males (drones) mate at spatially defined drone congregation areas (DCAs).
Here, we studied the temporal genetic structure of a DCA of A. dorsata over an 8-day time window by the genotyping of sampled drones with microsatellite markers. Analysis of the genotypic data
revealed a significant genetic differentiation between 3 sampling days and indicated that the DCA was used by at least two
subpopulations at all days in varying proportions. The estimation of the number of colonies which used the DCA ranged between
20 and 40 colonies per subpopulation, depending on the estimation procedure and population. The overall effective population
size was estimated as high as N
e=140. The DCA seems to counteract known tendencies of A. dorsata for inbreeding within colony aggregations by facilitating gene flow among subpopulations and increasing the effective population
size. 相似文献
136.
发展经济,保护环境,是社会主义经济建设不可忽视的两个方面。生态经济学是把两者作为统一体研究的学科。将城市生态学原理用于城镇布局,以节约能源,提高效益,减少污染,保护环境为目标,得出宜发展的四种城市类型;沿海城市,资源城市,内陆交通通枢纽城市和旅游城市。 相似文献
137.
Summary Acoustical signals emitted by dancing bees have recently been shown to transmit information about the location of food sources in the western honeybee, Apis mellifera. Towne (1985) reported that in the Asian honeybee species Apis dorsata, which builds a single comb in the open under overhanging rocks or tree branches, sound signals were not emitted by the dancers. This led to the conclusion that acoustical communication is restricted to bees that nest in the dark, like A. mellifera. Here we show that in fact A. dorsata produces dance sounds similar to those emitted by A. mellifera, and that these acoustical signals contain information about distance, direction and profitability of food sources. The acoustical transfer of information has thus evolved independently of nesting in dark cavities. The significance of nocturnal activity in Apis dorsata for the evolution of sound communication is discussed.
Correspondence to: W.H. Kirchner 相似文献
138.
139.
140.
为了研究双酚A(Bisphenol A,BPA)和壬基酚(Nonylphenol,NP)对河蚬(Corbicula fluminea)呼吸代谢能力和抗氧化酶活性的影响,探讨BPA和NP对河蚬的毒性作用。以河蚬为受试生物,采用半静态染毒法,研究了BPA和NP对河蚬的单一毒性等级、联合毒性作用类型和对河蚬耗氧率、排氨率以及抗氧化酶系统中SOD、CAT活性的影响。结果显示:① BPA、NP对河蚬的半致死质量浓度(96 h-LC50)分别为6.34和1.09 mg·L-1,毒性顺序为NP>BPA,二者均为高毒物质;② BPA-NP对河蚬毒性作用类型为协同作用;③亚急性毒性指标耗氧率、排氨率以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)对BPA、NP及二者混合物均比较敏感,在本试验的质量浓度范围内(BPA:0.63、0.79、1.59、3.17 mg·L-1;NP:0.109、0.136、0.271、0.542 mg·L-1;BPA+NP:(0.0782+0.029)、(0.0978+0.0363)、(0.196+0.0725)、(0.391+0.145) mg·L-1),河蚬耗氧率、排氨率以及两种酶活性变化均呈现先下降后上升再下降的趋势,其中在BPA、NP和二者混合物的质量浓度较低时,河蚬的耗氧率和排氨率、SOD和CAT活性只有微小降低,随着质量浓度的升高,河蚬耗氧率和排氨率、两个酶活性相对均有所升高,而在质量浓度极高时其耗氧率和排氨率以及两个酶活性才又受到显著性或极显著性的抑制。实验结果显示河蚬耗氧率、排氨率和SOD、CAT活性对水体中酚类内分泌干扰物反应敏感,具有较好的一致性和规律性,耗氧率、排氨率和SOD、CAT活性与其他敏感性指标一起可以作为酚类内分泌干扰物污染的一项早期监测指标。 相似文献