全文获取类型
收费全文 | 1424篇 |
免费 | 6篇 |
国内免费 | 42篇 |
专业分类
安全科学 | 45篇 |
废物处理 | 86篇 |
环保管理 | 142篇 |
综合类 | 240篇 |
基础理论 | 340篇 |
环境理论 | 1篇 |
污染及防治 | 394篇 |
评价与监测 | 100篇 |
社会与环境 | 118篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 13篇 |
2022年 | 45篇 |
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 14篇 |
2018年 | 54篇 |
2017年 | 22篇 |
2016年 | 28篇 |
2015年 | 49篇 |
2014年 | 35篇 |
2013年 | 119篇 |
2012年 | 36篇 |
2011年 | 63篇 |
2010年 | 61篇 |
2009年 | 72篇 |
2008年 | 70篇 |
2007年 | 60篇 |
2006年 | 44篇 |
2005年 | 43篇 |
2004年 | 77篇 |
2003年 | 66篇 |
2002年 | 43篇 |
2001年 | 102篇 |
2000年 | 43篇 |
1999年 | 24篇 |
1998年 | 16篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 20篇 |
1994年 | 7篇 |
1993年 | 9篇 |
1992年 | 15篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1980年 | 6篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1972年 | 12篇 |
1971年 | 5篇 |
1966年 | 5篇 |
1965年 | 5篇 |
1959年 | 5篇 |
1957年 | 5篇 |
排序方式: 共有1472条查询结果,搜索用时 19 毫秒
641.
Jeran Z Jaćimović R Batic F Mavsar R 《Environmental pollution (Barking, Essex : 1987)》2002,120(1):107-113
In this work an attempt to combine the results of lichen mapping with the quantitative levels of certain trace elements in Hypogymnia physodes (L.) Nyl. collected on a national scale is presented. An Index of Atmospheric Purity (IAP) was calculated using a simple method of mapping lichens based on the assessment of the cover and frequency of crustose, foliose and fruticose lichens on different tree species. For determination of trace elements in lichens k0-instrumental neutron activation analysis was used. From the IAP results it can be concluded that the epiphytic lichen flora look quite poor with more than 70% of the territory in the fourth and third classes, which represent highly polluted and moderately polluted air. By comparing IAP results with elemental levels in H. physodes using multivariate statistical methods it was found that the elemental levels do not have a direct negative effect on the diversity of lichens but can help in identification of the type of possible pollution sources and their origin. 相似文献
642.
643.
Interactions between arbuscular mycorrhizae and heavy metals under sand culture experiment 总被引:10,自引:0,他引:10
A sand culture experiment was established to determine interactions between arbuscular mycorrhizae and heavy metals. Mycorrhizal infection rates, spore densities, maize root and shoot weights, and heavy metal contents in maize were as indexes of responses of arbuscular mycorrhizal fungi (Acaulospora laevis, Glomus caledonium and Glomus manihotis) to heavy metals (Cu and Cd). The mycorrhizal infection rates of G. caledonium were the highest among these three mycorrhizal fungi, but the sporulating ability of G. caledonium was the poorest in the heavy metal treatments. The shoot and root weights of non-mycorrhizal plants were usually greater than those of mycorrhizal plants when the Cu concentrations in solutions are less than 3 mg l(-1) or Cd concentrations less than 1 mg l(-1). When Cd concentrations were 0.5 and 1 mg(-1), the root and shoot weights of plants inoculated with A. laevis were significantly (p < 0.05) lower than those of other treatments. Copper concentrations in shoots of mycorrhizal plants were higher than those of non-mycorrhizal ones at all Cu concentrations in solution, especially at low Cu concentrations. As to A. laevis, Cu concentrations in roots and shoots of the host were higher than those of non-mycorrhizal plants in these treatments. Thus A. laevis was sensitive to Cu and Cd, especially Cd, and G. caledonium was more tolerant to these two heavy metals. It is suggested that G. caledonium might be a promising mycorrhizal fungus for bioremediation of heavy metal contaminated soil. 相似文献
644.
Finkelstein ZI Baskunov BP Rietjens IM Boersma MG Vervoort J Golovleva LA 《Journal of environmental science and health. Part. B》2001,36(5):559-567
Transformation of teflubenzuron, the active component in the insecticide commercialized as Nomolt, by soil microorganisms was studied. It was shown that microorganisms, belonging to Bacillus, Alcaligenes, Pseudomonas and Acinetobacter genera are capable to perform the hydrolytic cleavage of the phenylurea bridge of teflubenzuron in different positions, especially active was Bacillus brevis 625. The structure of the intermediates formed was established using TLC, HPLC, mass-spectrometry and 19F NMR techniques. It was shown that for a dose range of 53-132 microM and upon 12 days of fermentation about 30% of the teflubenzuron was modified. About 10-15% was transformed into 2,6-difluorobenzamide, 3-5% into 2,6-difluorobenzoic acid, 10-12% into 2,4-difluoro-3,5-dichloro-aniline. The late compound gave rise to formation of a condensed compound, identified as 1,2-bis(2,4-difluoro-3,5-dichlorophenyl)urea with molecular mass of 420. The results obtained indicate degradation of teflubenzuron by soil microorganisms to be a process to be mediated by microbial consortia, and starting with hydrolysis of the phenylurea bridge by several bacterial species. Subsequent further degradation of the aromatic degradation products has to be mediated by other strains known to be capable of degradation of halogenated aromatics. 相似文献
645.
646.
13 hydrocarbons together with the known n-nonacosane were isolated by column chromatography from Canabis sativa extract. For separation and identification of the new compounds, the combined gas chromatography-masspectrometry technique was used. 相似文献
647.
A A L Zinatizadeh A R Mohamed M D Mashitah A Z Abdullah M Hasnain Isa 《Water environment research》2007,79(8):833-844
In the present study, characteristics of the granular sludge (including physical characteristics under stable conditions and process shocks arising from suspended solid overload, soluble organic overload, and high temperature; biological activity; and sludge kinetic evaluation in a batch experiment) developed in an upflow anaerobic sludge blanket fixed-film reactor for palm oil mill effluent (POME) treatment was investigated. The main aim of this work was to provide suitable understanding of POME anaerobic digestion using such a granular sludge reactor, particularly with respect to granule structure at various operating conditions. The morphological changes in granular sludge resulting from various operational conditions was studied using scanning electron microscopy and transmission electron microscopy images. It was shown that the developed granules consisted of densely packed rod- (Methanosaeta-like microorganism; predominant) and cocci- (Methanosarsina) shaped microorganisms. Methanosaeta aggregates functioned as nucleation centers that initiated granule development of POME-degrading granules. Under the suspended solid overload condition, most of the granules were covered with a thin layer of fiberlike suspended solids, so that the granule color changed to brown and the sludge volume index also increased to 24.5 from 12 to 15 mL/g, which caused a large amount of sludge washout. Some of the granules were disintegrated because of an acidified environment, which originated from acidogenesis of high influent organic load (29 g chemical oxygen demand [COD]/L d). At 60 degrees C, the rate of biomass washout increased, as a result of disintegration of the outer layer of the granules. In the biological activity test, approximately 95% COD removal was achieved within 72 hours, with an initial COD removal rate of 3.5 g COD/L d. During POME digestion, 275 mg calcium carbonate/L bicarbonate alkalinity was produced per 1000 mg COD(removed)/ L. A consecutive reaction kinetic model was used to simulate the data obtained from the sludge activity in the batch experiment. The mathematical model gave a good fit with the experimental results (R2 > 0.93). The slowest step was modeled to be the acidification step, with a rate constant between 0.015 and 0.083 hours(-1), while the rate constant for the methanogenic step was obtained to be between 0.218 and 0.361 hours(-1). 相似文献
648.
Z.?P.?McKiness E.?R.?McMullin C.?R.?Fisher C.?M.?CavanaughEmail author 《Marine Biology》2005,148(1):109-116
Until recently, the only major hydrothermal vent biogeographic province not known to include bathymodioline mussels was the spreading centers of the northeast Pacific, but deep-sea dives using DSV Alvin on the Endeavor segment of the Juan de Fuca Ridge (47°56N 129°06W; ∼2,200 m depth) in August 1999 yielded the only recorded bathymodioline mytilids from these northeastern Pacific vents. One specimen in good condition was evaluated for its relatedness to other deep-sea bathymodioline mussels and for the occurrence of chemoautotrophic and/or methanotrophic symbionts in the gills. Phylogenetic analyses of the host cytochrome oxidase I gene show this mussel shares evolutionary alliances with hydrothermal vent and cold seep mussels from the genus Bathymodiolus, and is distinct from other known species of deep-sea bathymodiolines, suggesting this mussel is a newly discovered species. Ultrastructural analyses of gill tissue revealed the presence of coccoid bacteria that lacked the intracellular membranes observed in methanotrophic symbionts. The bacteria may be extracellular but poor condition of the fixed tissue complicated conclusions regarding symbiont location. A single gamma-proteobacterial 16S rRNA sequence was amplified from gill tissue and directly sequenced from gill tissue. This sequence clusters with other mussel chemoautotrophic symbiont 16S rRNA sequences, which suggests a chemoautotrophic, rather than methanotrophic, symbiosis in this mussel. Stable carbon (δ13C = −26.6%) and nitrogen (δ15N = +5.19%) isotope ratios were also consistent with those reported for other chemoautotroph-mussel symbioses. Despite the apparent rarity of these mussels at the Juan de Fuca vent sites, this finding extends the range of the bathymodioline mussels to all hydrothermal vent biogeographic provinces studied to date. 相似文献
649.
To assess P losses to surface water by runoff during the rice season and by drainage flow during the winter wheat season, serial field trials were conducted in different types of paddy soils in the Tai Lake Region (TLR) during 2000 and 2001. Four P application rates were set as 0 (CK), 30, 150, and 300 kg P/hm2 for flooded rice trials and 0 (CK), 20, 80, 160 kg P/hm2 for winter wheat trials respectively. Field experiments were done in two locations with a plot size of 30 m2 and four replications in a randomized complete block design. A simplified lysimeter was installed for each plot to collect all the runoff or drainage flow from each event. Total P (TP) losses to surface water during rice season by runoff flow from four treatments were 150 (CK), 220 (T30), 395 (T150), 670 (T300) g P/hm2 in year 2000, and 298, 440, 1828, 3744 g P/hm2 in year 2001 respectively in Wuxi station, here the soil is permeable paddy soil derived from loam clay deposit. While the losses were 102, 140, 210, 270 in year 2000, and 128, 165, 359, 589 g P/hm2 in year 2001 respectively in Changshu station, here the soil is waterlogged paddy soil derived from silt loam deposit. During the winter wheat season, total P lost from the fields by drainage flow in the four treatments were 253 (CK), 382 (T20), 580 (T89), 818 (T160) g P/hm2 in year 2000–2001, and 573.3, 709.4, 1123.2, 1552.4 g P/hm2 in year 2001–2002 at the Wuxi station. While these were 395.6, 539.1, 1356.8, 1972.1 g P/hm2 in year 2000–2001, and 811.5, 1184.6, 3001.2, 5333.1 g P/hm2 in year 2001–2002 at the Changshu station. Results revealed that P fertilizer application rates significantly affected the TP concentrations and TP loads in runoff during the rice season, and by drainage flow during the winter wheat season. Both TP loads were significantly increased as the P application rate increases. The data indicate that TP losses to surface water were much higher during the winter wheat season than during the rice season in two tested sites. The data also reveal that the annual precipitation and evaporation rate affected the soil P losses to surface water significantly. Year 2000 was relatively dried with higher evaporation thus P losses to water by both runoff and drainage flow were less than in year 2001 which was a relatively wet year with lower evaporation. Results indicate that texture, structure of the soil profile, and field construction (with or without ridge and deep drains) affected soil P losses to surface water dramatically. Annual possible TP lost to water at the application rate of 50 kg P/hm2 year tested in TLR were estimated from 97 to 185 tones P from permeable paddy soils and 109–218 tones P from waterlogged paddy soils. There was no significant difference of TP lost between the CK and the T50 treatments in both stations, which indicate that there is no more TP lost in field of normal P fertilizer application rate than in control field of no P fertilized. Much higher TP lost in runoff or drainage flow from those other P application rates treatments than from the T50 treatment, which suggest that P losses to surface water would be greatly increasing in the time when higher available P accumulation in plough layer soil in this region. 相似文献
650.
Ahmad A Inam A Ahmad I Hayat S Azam ZM Samiullah 《Journal of environmental biology / Academy of Environmental Biology, India》2003,24(2):141-146
The crop of sugarcane (Saccharum officinarum) was grown at the agricultural farm of the Mathura Oil Refinery in a simple randomized block design. The experimental plots were irrigated with ground water (GW) or treated wastewater (TW) as and when required The plants gave better response to the latter than the former. The quantity of the required nutrients was comparatively more in TW than GW. The soil receiving wastewater did not show any significant change in its physico-chemical characteristics. The soil accumulated all the heavy metals but the plant samples receiving TW only exhibited the presence of Ni, Pb and Zn whose values are far below the permissible limits. 相似文献