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31.
Karlsson PE Pleijel H Belhaj M Danielsson H Dahlin B Andersson M Hansson M Munthe J Grennfelt P 《Ambio》2005,34(1):32-40
Ground level ozone concentrations, in combination with the prevailing climate, at the estate Ostads S?teri in southwestern Sweden were estimated to reduce the yield of wheat and potato ranging between 5% and 10%. Occasionally, in years with the highest ozone concentrations and/or climatic conditions favoring high rates of ozone uptake to the leaves, yield loss levels above 10% may occur. Based on simple extrapolation, these ozone-induced reductions of crop yields at Ostads S?teri represent a potential total annual yield loss in Sweden in the range of 24.5 million Euro for wheat and 7.3 million Euro for potato, respectively. A simulation of forest growth at Ostad S?teri predicted that prevailing mean ozone exposure during 1993-2003 had the potential to reduce forest growth by 2.2% and the economic return of forest production by 2.6%. Using this value for extrapolation to the national level, the potential annual economic loss for Sweden due to negative impacts of ozone on forest production would be in the range of 56 million Euro (2004 prices). 相似文献
32.
Karlsson PE Uddling J Skärby L Wallin G Selldén G 《Environmental pollution (Barking, Essex : 1987)》2003,124(3):485-495
Saplings of one half-sib family of birch, Betula pendula, were exposed to three levels of ozone in open-top chambers (OTCs) during two growing seasons 1997-1998. The ozone treatments were non-filtered air (NF, accumulated daylight AOT40 over the two growing seasons of 3.0 l l-1 h), non-filtered air with extra ozone (NF+, accumulated daylight AOT40 of 27.3 l l-1 h) and non-filtered air with additional extra ozone (NF++, accumulated daylight AOT40 of 120 l l-1 h). The birch saplings, including the roots, were harvested after the first and second growing seasons. After the first growing season, the NF++ treatment reduced the total wood biomass by 22%, relative to the NF treatment. There was no further reduction of the total wood biomass in the NF++ treatment after the second growing season. The root biomass was reduced by 30% after the first growing season. The shoot/root ratio, as well as the proportional biomass of leaves, were increased by ozone during both years. The ozone impact on the relative growth rate was estimated to -2% per 10 l l-1 h daylight AOT40 per growing season. 相似文献
33.
34.
Håkan Karlsson Johan Bäckman Cecilia Nilsson Thomas Alerstam 《Behavioral ecology and sociobiology》2010,64(12):2021-2031
Using tracking radars, we investigated the variability of flight directions of long-distance nocturnal passerine migrants
across seasons (spring versus autumn migration) and sites at the southern (56° N) and northern (68° N) ends of the Scandinavian
Peninsula (Lund versus Abisko). Whilst most migrants at Lund are on passage to and from breeding sites in Fennoscandia, the
majority of the migrants at Abisko are close to their breeding sites, and migration at Abisko thus to a large degree reflects
initial departure from breeding sites (autumn) or final approach to breeding destinations (spring). The radar data were used
to test predictions about differences in orientation and wind drift effects between adult and juvenile birds (a large proportion
of autumn migrants consists of juvenile birds on their first journey), between situations far away from or near the goals
and between different phases of migration (initial departure, en route passage, final approach to goal). The concentrations
(both total and within-night concentrations) of flight directions differed significantly between seasons as well as sites,
with the highest concentration at Lund in spring (mean vector length of track directions, r = 0.79) and lowest at Abisko during spring (r = 0.35). Partial wind drift and partial compensation were recorded at Lund, with a similar effect size in spring and autumn,
whilst possible wind drift effects at Abisko were obscured by the large directional scatter at this site. The results from
Lund support the prediction that the high proportion of juveniles in autumn contributes to increase the directional scatter
during this season, whilst there was no support for predictions of differential wind drift effects between seasons and situations
with different goal distances. The most striking and surprising result was the exceedingly large scatter of flight directions
at Abisko, particularly in spring. We suggest that such an exaggerated scatter may be associated with final approach orientation,
where migrants reach their specific goals from all various directions by final navigation within a more wide-ranging goal
region. The larger scatter of autumn flight directions at Abisko compared to Lund may be due to exploratory flights in variable
directions being more common at initial departure from breeding sites than later during migratory passage. These surprising
results highlight the importance of studying and analysing orientation during final approach to (and initial departure from)
migratory goals for understanding the orientation systems of migratory birds. 相似文献
35.
A major restructuring of the mining industry has been going on since the early 1980s. Using 11 important minerals this paper analyses the changing pattern of control in the mining industry for European based mining companies. In general, European mining companies have increased their control over mineral production worldwide while North American based companies have shown a decline in control of production. Production of European state-owned mining companies has declined as a result of privatization. 相似文献
36.
The degradation products of polymers are identifiable by chromatography. The degradation product patterns (or fingerprints) formed depend on the type of polymer, the degradation mechanism(s), and also the type of additive present in the material. The chromatographic fingerprint of biotically aged degradable low-density polyethylene (i.e., LDPE+starch+prooxidant) shows, in particular, the absence of low molecular weight carboxylic acids, which suggests an assimilation of these carboxylic acids by the microorganisms. The degradation products of natural polymers are usually intermediates that are used again in the anabolic cycles. It is possible to transfer the terminology from the natural polymers, where the catabolism of natural polymers consists of three stages, and apply this also to the degradable synthetic polymers. During stage I the natural polymers degrade to their major building blocks (e.g., amino acids, glycerol, hexoses, pentoses, etc.), during stage II these products are collected and converted to a smaller number of even simpler molecules [e.g., acetyl-coenzyme A (CoA)]. In stage III, finally, the acetyl-CoA enters the citric acid cycle, where energy is gained in parallel with the release of CO2 and H2O.Presented at the international workshop,Polymers from Renewable Resources and their Degradation, Stockholm, Sweden, November 10–11, 1994. 相似文献
37.
波罗的海鱼类和甲壳类的毒性物质及繁殖失调 总被引:1,自引:0,他引:1
Magnus Breitholtz Carthy Hill Bengt-Erik Bengtsson 《Ambio-人类环境杂志》2001,30(4):210-216
在波罗的海生态系统中,由于毒性物质(例如DDT,PCB)的生物积累作用,在食物链上层捕食者(如海豹和食鱼鸟类)中已出现了繁殖失调.在过去25年间繁殖失调还影响到鱼类.然而,还没有强有力的证据说明这些问题是有毒物质引起的.更确切地说,这种失调似乎是由两种以上生物或生物的因素共同引起的.杀死鲑鱼和鳟鱼幼体的M74综合症,是由于缺乏硫胺素(维生素B1).许多因素可以导致维生素B1缺乏,包括鲑鱼的食物和卤代有机化合物.鳕鱼不生M74病,其资源得不到恢复是由于繁殖区域溶解氧缺乏和过度捕捞.肉类加工厂排放物中的毒性物质,而不是机械作用和活性物质,抑制了生殖腺的发育.肉类加工厂所在海域的外侧鱼类资源缺乏可以解释为幼鱼缺乏食物,而不是繁殖失败.有关波罗的海甲壳类繁殖失调的资料很少.大部分资料都是关于端足类Monoporeoaaffnis的研究,该种生物已被用于监测计划.该种生物的繁殖失调现象例如胚胎畸形、死亡,以及雌雄性不同时成熟等已有报道. 相似文献
38.
Karlsson PE Medin EL Ottosson S Selldén G Wallin G Pleijel H Skärby L 《Environmental pollution (Barking, Essex : 1987)》2004,128(3):405-417
Norway spruce saplings [Picea abies (L.) Karst.] were exposed during four growing seasons to different ozone treatments in open-top chambers: charcoal filtered air (CF), non-filtered air (NF) and non-filtered air with extra ozone (NF+, 1.4xambient concentrations). The CF and NF+ ozone treatments were combined with phosphorous deficiency and drought stress treatments. The total biomass of the trees was harvested at different intervals during the experimental period. The ozone uptake to current-year needles of the Norway spruce saplings was estimated using a multiplicative stomatal conductance simulation model. There was a highly significant correlation between the reduction of total biomass and the estimated cumulative ozone uptake, which did not vary when different thresholds were applied for the rate of ozone uptake. The reduction of the total biomass was estimated to 1% per 10 mmol m(-2) cumulated ozone uptake, on a projected needle area basis. 相似文献
39.
Surface water and aqueous solutions of isolated organic matter from a humic rich lake in southern Sweden were exposed to artificial UV radiation to investigate the UV light induced influence on organic matter bound chlorine in natural systems. It was found that the photodegradation of organic matter bound chlorine was more pronounced than the photodegradation of organic carbon. After 120 h of irradiation of the isolated organic matter, only 35% of the initial organochlorine was still in the solution compared to about 70% of the dissolved organic carbon (DOC). A similar result was obtained for unfractionated surface water. Furthermore, our results indicate that the loss of organic chlorine was mainly due to a mineralization of organic chlorine into chloride ions. The total decrease of organic chlorine after 120 h was 32 microg Cl(org) l(-1), of which the major part disappeared in the initial irradiation phase. A similar increase was observed in the chloride concentration (34 microg Cl(-) l(-1)). 相似文献
40.
Performance of three-phase three-dimensional electrode reactor for the reduction of COD in simulated wastewater-containing phenol 总被引:18,自引:0,他引:18
The removal of chemical oxygen demand (COD) from wastewater-containing phenol was investigated using three-phase three-dimensional electrode reactor. Special attention was paid to experimentally probe the performance of the reactor in COD removal in the process of repeated batch runs. The experimental results showed that the reactor could remove COD from phenol-containing wastewater much more efficiently than both granulated activated carbon (GAC) adsorption bed and conventional three-dimensional electrode. For 200th batch run, the three-phase three-dimensional electrode reactor with an airflow of 5 l min(-1) and a cell voltage of 30 V could remove 1350 ppm COD from the wastewater in 30 min while conventional three-dimensional electrode reactor with a same cell voltage and GAC adsorption bed with a same airflow only could remove 610 and 1000 ppm, respectively, at the same reaction duration. Although it was found that COD removal decreased with increasing repeated batch runs in our experimental range, due to adsorption saturation of GAC and electrode passivation, the extent of decrease for the three-phase three-dimensional electrode is much less than those for conventional three-dimensional electrodes and GAC adsorption beds. The passivated reactor could be partly re-activated by electrolysis in the presence of MnO2. 相似文献