全文获取类型
收费全文 | 16872篇 |
免费 | 159篇 |
国内免费 | 126篇 |
专业分类
安全科学 | 828篇 |
废物处理 | 667篇 |
环保管理 | 1879篇 |
综合类 | 3263篇 |
基础理论 | 4349篇 |
环境理论 | 4篇 |
污染及防治 | 4048篇 |
评价与监测 | 1061篇 |
社会与环境 | 963篇 |
灾害及防治 | 95篇 |
出版年
2022年 | 128篇 |
2021年 | 104篇 |
2020年 | 100篇 |
2019年 | 106篇 |
2018年 | 195篇 |
2017年 | 234篇 |
2016年 | 329篇 |
2015年 | 269篇 |
2014年 | 454篇 |
2013年 | 1231篇 |
2012年 | 492篇 |
2011年 | 694篇 |
2010年 | 620篇 |
2009年 | 585篇 |
2008年 | 675篇 |
2007年 | 718篇 |
2006年 | 589篇 |
2005年 | 516篇 |
2004年 | 680篇 |
2003年 | 659篇 |
2002年 | 556篇 |
2001年 | 687篇 |
2000年 | 475篇 |
1999年 | 255篇 |
1998年 | 217篇 |
1997年 | 217篇 |
1996年 | 209篇 |
1995年 | 286篇 |
1994年 | 276篇 |
1993年 | 213篇 |
1992年 | 223篇 |
1991年 | 202篇 |
1990年 | 230篇 |
1989年 | 209篇 |
1988年 | 181篇 |
1987年 | 186篇 |
1986年 | 170篇 |
1985年 | 167篇 |
1984年 | 159篇 |
1983年 | 153篇 |
1982年 | 135篇 |
1981年 | 125篇 |
1980年 | 116篇 |
1979年 | 129篇 |
1978年 | 100篇 |
1977年 | 114篇 |
1975年 | 94篇 |
1974年 | 91篇 |
1973年 | 104篇 |
1913年 | 112篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
911.
Inna P. Solyanikova Andrej L. Mulyukin Natalja E. Suzina Galina I. El-Registan Ludmila A. Golovleva 《Journal of environmental science and health. Part. B》2013,48(7):638-647
The goals of the present work were as follows: to obtain the dormant forms of R. opacus 1cp; to study the phenotypic variability during their germination; to compare phenotypic variants during the growth on selective and elective media; and to reveal changes in the ability of the strain to destruct xenobiotics that had not been degradable before dormancy. It was shown that Rhodococcus opacus 1cp (the strain degrading chlorinated phenols) became able to utilize a broader spectrum of xenobiotics after storage in the dormant state. Germination of the dormant forms of R. opacus 1cp on an agarized medium was followed by emergence and development of phenotypic variants that could grow on 4-chlorophenol and 2,4,6-trichlorophenol without adaptation. The cells of R. opacus 1cp phenotypic variants also utilized all of the tested chlorinated phenols: 2,3-, 2,5-, and 2,6-dichloro-, 2,3,4- and 2,4,5-trichloro-, pentachlorophenol, and 1,2,4,5-tetrachlorobenzene in concentrations up to 60 mg/L, though at the lower rates than 4-CP and 2,4,6-TCP. The improved degradation of chlorinated phenols by R. opacus strain 1cp exposed to the growth arrest conditions demonstrates the significance of dormancy for further manifestation of the adaptive potential of populations. A new principle of selection of variants with improved biodegradative properties was proposed. It embraces introduction of the dormancy stage into the cell life cycle with subsequent direct inoculation of morphologically different colonies into the media with different toxicants, including those previously not degraded by the strain. 相似文献
912.
P. Janaki R. Sathya Priya C. Chinnusamy 《Journal of environmental science and health. Part. B》2013,48(11):941-947
Oxyfluorfen, a diphenyl-ether herbicide is being used to control annual and perennial broad-leaved weeds and sedges in a variety of field crops including onion. The present study was aimed to investigate the dynamics and field persistence of oxyfluorfen in onion plant, bulb and soil under Indian tropical conditions. Application of four rates of oxyfluorfen viz., 200, 250, 300 and 400 g AI ha?1 as pre-emergence gave good weed control in field experiment with onion. The oxyfluorfen residue dissipated faster in plant than in soil respectively, with a mean half-life of 6.1 and 11.2 days. Dissipation followed first-order kinetics. In laboratory column leaching experiments, 17 percent of the applied oxyfluorfen was recovered from the soil and indicates its solubility in water and mobility in sandy clay loam soil was low. A sorption study revealed that the adsorption of oxyfluorfen to the soil was highly influenced by the soil organic carbon with the Koc value of 5450. The study concludes that the dissipation of oxyfluorfen in soil and onion was dependent on the physico-chemical properties of the soil and environmental conditions. 相似文献
913.
S.K. Kashyap J.P. Jani H.N. Saiyed S‐K. Gupta 《Journal of environmental science and health. Part. B》2013,48(4-5):479-489
Abstract Phorate (Thimet), an aliphatic derivative of phospnorus is a hignly toxic insecticide. In order to implement the safety measures, the clinical manifestations and cholinesterase (ChE) activity were evaluated before and after 2 weeks of exposure to this insecticide in 40 male tormulators. The 2 week's exposure reveal signs and symptoms of toxicity in 60% of the formulators. Gastrointestinal symptoms and lowering of heart rate (bradycardia) were more prominent as compared to the neurological symptoms. A significant depression in plasma ChE activity was observed at the end of 1st week (55%) and 2nd week (71%) as compared to the respective pre‐exposure values. A recovery up to 79% of the pre‐exposure activity of this enzyme was noticed 10 days after cessation of the above exposure. 相似文献
914.
Ernest Hodgson Arun P. Kulkarni David L. Fabacher Karen M. Robacker 《Journal of environmental science and health. Part. B》2013,48(6):723-754
Abstract The induction of drug metabolizing enzymes in mammals is summarized including both enzymes of the cytochrome P‐450‐dependent microsomal mixed function oxidase system and glutathione S‐transferases. Particular emphasis is placed on the role of pesticides as inducers, the early work being summarized while investigations carried out at North Carolina State University are considered in greater detail. Finally, the possible significance of induction is considered. 相似文献
915.
J. Jacobson A. Kuja D. Shriner S. Perrigan P. Irving J. Lee 《Journal of the Air & Waste Management Association (1995)》2013,63(6):777-783
Radish plants were exposed three times per week to simulated acidic rain at pH values of 2.6 to 5.4 over the course of four weeks in trials performed at Argonne, Illinois; Ithaca and Upton, New York; Corvallis, Oregon; Oak Ridge, Tennessee; and Toronto, Canada. Uniform genotype, soil media and planting techniques, treatment procedures, biological measurements, and experimental design were employed. Growth of plants differed among trials as a result of variation in greenhouse environmental conditions according to location and facilities. Larger plants underwent greater absolute but lower relative reductions in biomass after exposure to the higher levels of acidity. A generalized Mitscherlich function was used to model the effects of acidity of simulated rain or dry mass of hypocotyls using data from three laboratories that performed duplicate trials. The remaining data, from three other laboratories that performed only one trial each, were used to test the model. When the laboratory by trial effect was removed (influence of different growth. conditions), lack of fit to the Mitscherlich function was insignificant. Thus, a single mathematical model satisfactorily characterized the relationship between acidity and mean plant response. The pH value associated with a 10 percent reduction in mass was 3.3 ± 0.3 for hypocotyls. No value was estimated for shoots because effects oh shoots were not significant. The results of this study demonstrate that a generalized exposure-response model can be developed in the presence of large variations in environmental conditions when plant culture and exposure to simulated rain are standardized among laboratories. 相似文献
916.
Robert J. Tidona Ahtisham A. Nizami Nicholas P. Cernansky 《Journal of the Air & Waste Management Association (1995)》2013,63(6):806-811
Experiments were carried out to determine the relative chemiluminescence quenching efficiencies as a function of third body concentration for each of the common combustion products, H2O, CO2, CO, H2, O2 and Ar. These results are compared with those of other investigators. The effect of reaction chamber pressure on analyzer response and the development of an analyzer design which incorporates an adjustable sample capillary inlet capable of maintaining a constant molar flow rate of sample gas to the reaction chamber are discussed. The effect of carbon monoxide interference on chemiluminescent NOx measurement has been isolated and found to be significant. A means of correcting NO, measurements for these CO interference effects is described. Quantification of NO and NO2 absorption in liquid water in NOx sampling systems has been made. Recommendations for sample system designs to handle the presence of water in the sample gas are made. 相似文献
917.
A. P. Altshuller 《Journal of the Air & Waste Management Association (1995)》2013,63(7):936-943
The observed ranges in nonmethane organic compound (NMOC) concentrations, NMOC composition and nitrogen oxides (NOX) concentrations have been evaluated for urban and nonurban areas at ground level and aloft of the contiguous United States. The ranges in NMOC to NOX ratios also are considered. The NMOC composition consistently shifts towards less reactive compounds, especially the alkanes, in air parcels over nonurban areas compared to the NMOC composition near ground level within urban areas. The values for the NMOC to NOX ratios, 1.2 to 4.2, in air aloft over nonurban areas are lower than in air at ground level urban sites, ≥8, and much lower than in air at ground level nonurban sites, ≥20. The layers of air aloft over a number of nonurban areas of the United States tend to accumulate NOX emissions from the tall stacks of large fossil fuel power plants located at nonurban sites. During the night into the morning hours, the air aloft is isolated from any fresh NMOC emissions predominately coming from near surface sources. Conversely, during this extended period of restricted vertical mixing, air near the surface accumulates NMOC emissions while this air is isolated from the major NOX sources emitting aloft. These differences in the distribution of NMOC and NOX sources appear to account for the much larger NMOC to NOX ratios reported near ground level compared to aloft over nonurban areas. Two types of experimental results are consistent with these conclusions: (1) observed increases in surface rural NOX concentrations during the morning hours during which the mixing depth increases to reach the altitude at which NOX from the stacks of fossil fuel power plants is being transported downwind; (2) high correlations of total nitrate at rural locations with Se, which is a tracer for coal-fired power plant NOX emissions. The implications of these conclusions from the standpoint of air quality strategies are suggested by use of appropriate scenarios applied to both urban and regional scale photochemical air quality models. The predictions from urban model scenarios with NMOC to NOX ratios up to 20 are that NOX control will result in the need for the control of more NMOC emissions than necessary in the absence of NOX control, in order to meet the O3 standard. On a regional scale, control of NOX emissions from fossil fuel power plants has little overall effect regionally but does result on a more local scale in both small decreases and increases in O3 concentrations compared to the baseline scenario without NOX control. The regional modeling results obtained to date suggest that NOX control may be effective in reducing O3 concentrations only for a very limited set of conditions in rural areas. 相似文献
918.
919.
Martin A. Cohen P. Barry Ryan Yukio Yanagisawa John D. Spengler Halûk Özkaynak Paul S. Epstein 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1086-1093
The Kanawha Valley region of West Virginia which is comprised of Charleston and surrounding communities Is the center of a heavily industrialized area known for its chemical manufacturing. As part of a larger study designed to investigate the Impact of the chemical industry on human exposures to volatile organic compounds (VOC), a study of the relationship between indoor and outdoor concentrations was conducted. Thirty-five homes were selected for monitoring from among volunteers; approximately ten in each of three distinct population-industry centers and four outside the Valley to act as controls. Monitoring was performed using passive, badge samplers with a three-week monitoring period. Two separate questionnaires were administered: one for characterization of the residence; and one to characterize source use during monitoring. Participants were also asked to keep a record of their activities with respect to in-home, outdoors and other Indoor environments. Analysis of the samplers was performed by solvent extraction followed by gas chromatography using a flame-ionization detector. Results suggest that indoor VOC concentrations are higher than outdoor concentrations. Additionally, certain ventilation-related parameters were identified that afforded some predictive power for indoor concentrations. No statistically significant differences between regions were identified. 相似文献
920.
Viney P. Aneja Candis S. Claiborn Zheng Li Anuradha Murthy 《Journal of the Air & Waste Management Association (1995)》2013,63(2):217-220
Abstract This paper presents a comparative study of the biodegradation of three aromatic volatile compounds in a compost-based biofilter: toluene, xylene, and 1,2,4-trimethyl-benzene, used in the course of this work for the first time in the field of biofiltration. Hence, three identical biofiltration units have been operated at the laboratory scale. During the experiments, nitrogen (as urea) was supplied at various concentrations to each reactor, via irrigated nutrient solutions. A comparative analysis of the results showed that the biodegradability scale followed the degree of substitution around the aromatic ring: toluene > xylene > trimethylbenzene, with 95, 80, and 70% maximum conversions, respectively. In addition, and despite the different removal levels achieved in the three biore-actors, it was established that from a reaction viewpoint, the degradation of the three compounds seemed to follow similar metabolic pathways involving methylcatechol isomers. Finally, by varying the nitrogen input concentrations in the three reactors, three degradation regimes have been highlighted: an N-limitation regime and an N-optimum regime, common to the three solvents, and an N-excess regime, favorable to the colonization of the filter beds by nitrifying species, which particularly affected the xylene and trimethylbenzene biodegradation. 相似文献