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871.
Ana B. Payá-Pérez Mohammed S. Rahman Helle Skejø-Andresen Bo R. Larsen 《Environmental science and pollution research international》1996,3(4):183-188
The soil/water partition coefficient (Kd) of hexachlorobenzene (HCB) ranged from 220 1/kg to 1800 1/kg for eight soils having a wide range of physico-chemical properties. Kd normalised to soil organic carbon (Koc) was found to be 28000 ± 4800 1/kg. Anionic surfactant dodecylsulphate (DS) present at concentrations above the critical micellar concentration (CMC) caused reductions in the apparent soil/water partition coefficient (Kd *) in the range of 3–26 times for most soils and up to 36–91 times for sandy soils. Below CMC, at environmentally relevant surfactant concentrations, Kd * was reduced by a factor of 1–13. For clay and calcareous soils significant adsorption/complexation/precipitation of DS occurred. At the lowest DS concentration this produced a two-fold increase in Kd *. At increasing DS concentrations this effect was shielded by the solubihzing effect from DS. Monomer (Kmn) and micellar (Kmc) surfactant/water partition coefficients for HCB were determined to be, 980 ± 190 1/kg and 21000 ± 1600 1/kg, respectively. 相似文献
872.
Spring wheat (Triticum aestivum L. cv. Turbo) was exposed to different levels of ozone and water supply in open-top chambers in 1991. Air was charcoal filtered (CF), non-filtered (NF) and CF plus proportional addition of ambient or twice ambient ozone (CF1, CF2). Seasonal means of O(3), taken over 24 h, were 2.3, 20.6, 17.3, and 34.5 nl litre(-1) for CF, NF, CF1 and CF2 treatments, respectively. A split-plot design was used to obtain two levels of water supply: one-half of the pots was irrigated sufficiently not to show any symptoms of drought stress; the others were exposed to low water supply and received 50% of these amounts. Using a steady-state porometer approximately 800 measurements of stomatal conductance (g(s)) were made on flag leaves from 68 to 106 days after sowing. The measurements yielded only small differences of maximum conductance between the two levels of water supply. Therefore, low water supply did not protect wheat plants against ozone injury via reduced stomatal uptake in this experiment. To describe the effects of environmental variables on the stomatal behaviour, boundary-line analysis and non-linear regression analysis were used. Besides microclimatic parameters, the ozone dose of flag leaves was introduced as an independent variable affecting stomatal aperture. A well-defined boundary line for ozone dose was found, suggesting that increasing ozone dose caused stomatal closure in wheat flag leaves. But at high ozone doses, co-acting senescence seems also responsible for the decrease in stomatal conductance. A multiplicative boundary-line model was used to predict stomatal conductance from combinations of environmental variables. In the test carried out with the measurements of stomatal conductance, the model accounted only for 40% of the variation of g(s). Generalized stomatal response patterns of the herbaceous growth form, the dependence of the variables' age and ozone dose and the lack of an important factor influencing stomatal response (water status of the plant) in the model, are suggested as explanations of the poor results of the test. 相似文献
873.
Sjödin A Cooper DA Andréasson K 《Journal of the Air & Waste Management Association (1995)》1995,45(3):186-190
Ambient air measurements of N2O, NOx, CO, and HC based on grab sampling were conducted in a major traffic tunnel in Sweden, that carries up to 4,000 vehicles per hour, in order to estimate real-world emissions of N2O for road traffic. Two different methods--relative and mass balance-were used to calculate a N2O emission factor for the mixed vehicle fleet, which gave an average emission factor, at average speeds of 30-70 km/h, of approximately 25 mg N2O/ km, with a range of 7-56 mg/km. 相似文献
874.
Forsberg A Söderlund S Frank A Petersson LR Pedersén M 《Environmental pollution (Barking, Essex : 1987)》1988,49(4):245-263
Concentrations of eleven metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) were determined in the brown seaweed Fucus vesiculosus collected from the Archipelago of Stockholm. Several factors which influence the metal content in the seaweed have been studied, including errors caused by epiphytes, sea exposure and differences depending on which part of the seaweed is analysed. It is concluded that, if all these factors are considered, Fucus vesiculosus plants are excellent bio-indicators of metal pollution. This is also demonstrated by a significant increase in metal content in transplanted Fucus vesiculosus near the city of Stockholm. The results from this investigation also indicate increasing metal concentrations, especially Cd, in samples from the northern parts of the Archipelago and the reason for this is discussed. 相似文献
875.
Adama Ndao Lalit R Kumar Rajeshwar. D. Tyagi Jose Valéro 《Journal of environmental science and health. Part. B》2020,55(2):115-126
AbstractThe aim of this study was to produce Bacillus thuringiensis-based biopesticide using starch-producing industry wastewater (SIW) fortified with soybean medium and optimize the formulated product using different adjuvants. This study was necessary as low endotoxin concentration is obtained in formulated biopesticide when SIW alone is used as fermentation medium. The fermentation runs were conducted using SIW alone and SIW fortified with 25% soybean (w/v) medium in 2000?L and 150?L bioreactor, respectively. SIW supplemented with soybean medium showed an increase in cell count (from 1.95?×?108 to 1.65?×?109 CFU mL–1), spore synthesis (from 1.5?×?108 to 1.35?×?109 CFU mL–1) and endotoxin concentration (from 436 to 1170?μg mL–1) when compared to SIW medium alone. The fermented broth was concentrated using continuous centrifugation and adjuvants were added for biopesticide formulation in order to enhance its resistance against UV rays and rainfastness. Entomotoxicity of the formulation produced using fermented broth of SIW fortified with soybean (38,000?IU μL–1) was higher than that obtained by SIW medium alone (21,000?IU μL–1), commercial biopesticide Foray 76B (20,000?IU μL–1) and Btk sander’s (12,500?IU μL–1). 相似文献
876.
Polycyclic aromatic hydrocarbons, black carbon, and molecular markers in soils of Switzerland 总被引:16,自引:0,他引:16
Polycyclic aromatic hydrocarbons (PAH) were analysed in 23 soil samples (0–10 cm layer) from the Swiss soil monitoring network (NABO) together with total organic carbon (TOC) and black carbon (BC) concentration, as well as some PAH source diagnostic ratios and molecular markers. The concentrations of the sum of 16 EPA priority PAHs ranged from 50 to 619 μg/kg dw. Concentrations increased from arable, permanent and pasture grassland, forest, to urban soils and were 21–89% lower than median numbers reported in the literature for similar Swiss and European soils. NABO soils contained BC in concentrations from 0.4 to 1.8 mg/g dw, except for two sites with markedly higher levels. These numbers corresponded to 1–6% of TOC and were comparable to the limited published BC data in soil and sediments obtained with comparable analytical methods. The various PAH ratios and molecular markers pointed to a domination of pyrogenically formed PAHs in Swiss soils. In concert, the gathered data suggest the following major findings: (1) gas phase PAHs (naphthalene to fluorene) were long-range transported, cold-condensated at higher altitudes, and approaching equilibrium with soil organic matter (OM); (2) (partially) particle-bound PAHs (phenanthrene to benzo[ghi]perylene) were mostly deposited regionally in urban areas, and not equilibrated with soil OM; (3) Diesel combustion appeared to be a major emission source of PAH and BC in urban areas; and (4) wood combustion might have contributed significantly to PAH burdens in some soils of remote/alpine (forest) sites. 相似文献
877.
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
878.
Chlorination of bisphenol A: kinetics and by-products formation 总被引:6,自引:0,他引:6
The kinetics of initial chlorination of bisphenol A (BPA) was studied between pH 2 and 11 at room temperature (20 +/- 2 degrees C). pH Profile of the apparent second-order rate constant of the reaction of BPA with chlorine were modeled considering the elementary reactions of HOCl with BPA species and an acid-catalyzed reaction. The predominant reactions at near neutral pH were the reactions of HOCl with the two phenolate species of BPA (k = 3.10 x 10(4) M(-1)s(-1) for BPA- and 6.62 x 10(4) M(-1) s(-1) for BPA(2-)). At near neutral pH, half-life times of BPA were calculated to be less than 1.5 h for chlorine residual higher than 0.2 mg l(-1). Chlorination of synthetic treated waters spiked with BPA showed that BPA disappeared within 4 h and that chlorinated bisphenol A congeners were rapidly formed and remained in solution for up to 10-20 h when low chlorine dosages are applied (0.5-1 mg l(-1)). To limit their presence in drinking water networks, it is then necessary to maintain high chlorine residuals that rapidly produce and decompose chlorinated bisphenol A congeners. 相似文献
879.
Jean-Paul Schwitzguébel Hailong Wang 《Environmental science and pollution research international》2007,14(7):446-544
Goal, Scope and Background Aquaculture activities are well known to be the major contributor to the increasing level of organic waste and toxic compounds
in the aquaculture industry. Along with the development of intensive aquaculture in China, concerns are evoked about the possible
effects of everincreasing aquaculture waste both on productivity inside the aquaculture system and on the ambient aquatic
ecosystem. Therefore, it is apparent that appropriate waste treatment processes are needed for sustaining aquaculture development.
This review aims at identifying the current status of aquaculture and aquaculture waste production in China.
Main Features China is the world’s largest fishery nation in terms of total seafood production volume, a position it has maintained continuously
since 1990. Freshwater aquaculture is a major part of the Chinese fishery industry. Marine aquaculture in China consists of
both land-based and offshore aquaculture, with the latter mostly operated in shallow seas, mud flats and protected bays. The
environmental impacts of aquaculture are also striking.
Results Case studies on pollution hot spots caused by aquaculture have been introduced. The quality and quantity of waste from aquaculture
depends mainly on culture system characteristics and the choice of species, but also on feed quality and management. Wastewater
without treatment, if continuously discharged into the aquatic environment, could result in remarkable elevation of the total
organic matter contents and cause considerable economy lost. Waste treatments can be mainly classified into three categories:
physical, chemical and biological methods.
Discussion The environmental impacts of different aquaculture species are not the same. New waste treatments are introduced as references
for the potential development of the waste treatment system in China. The most appropriate waste treatment system for each
site should be selected according to the sites’ conditions and financial status as well as by weighing the advantages and
disadvantages of each system. Strategies and perspectives for sustainable aquaculture development are proposed, with the emphasis
on environmental protection.
Conclusions Negative effects of waste from aquaculture to aquatic environment are increasingly recognized, though they were just a small
proportion to land-based pollutants. Properly planned use of aquaculture waste alleviates water pollution problems and not
only conserves valuable water resources but also takes advantage of the nutrients contained in effluent. It is highly demanding
to develop sustainable aquaculture which keeps stocking density and pollution loadings under environmental capacity.
Recommendations and Perspectives The traditional procedures for aquaculture waste treatment, mainly based on physical and chemical means, should be overcome
by more site-specific approaches, taking into account the characteristics and resistibility of the aquatic environment. Further
research needs to improve or optimize the current methods of wastewater treatment and reuse. Proposed new treatment technology
should evaluate their feasibility at a larger scale for practical application.
ESS-Submission Editor: Dr. Ding Wang (wangd@ihb.ac.cn) 相似文献
880.
Hernández-Huesca R Braos-García P Mérida-Robles J Maireles-Torres P Rodríguez-Castellón E Jiménez-López A 《Chemosphere》2002,48(4):467-474
A series of cobalt containing alumina pillared zirconium phosphate materials have been prepared by ion exchange or by impregnation, and fully characterised. The catalytic behaviour of these materials in the selective catalytic reduction of NO by propane, in excess of oxygen, at temperatures ranging between 350 and 550 degrees C, has been also evaluated. A maximum NO conversion close to 14% is obtained on Co-impregnated catalysts heated at 600 degrees C. The NO reduction seems to be related to the presence of Co3+, thus the calcination temperature of samples influences the resulting activity much more than the cobalt content. 相似文献