全文获取类型
收费全文 | 12226篇 |
免费 | 109篇 |
国内免费 | 52篇 |
专业分类
安全科学 | 341篇 |
废物处理 | 443篇 |
环保管理 | 1694篇 |
综合类 | 2246篇 |
基础理论 | 3198篇 |
环境理论 | 7篇 |
污染及防治 | 3000篇 |
评价与监测 | 740篇 |
社会与环境 | 633篇 |
灾害及防治 | 85篇 |
出版年
2023年 | 76篇 |
2022年 | 110篇 |
2021年 | 113篇 |
2020年 | 102篇 |
2019年 | 115篇 |
2018年 | 167篇 |
2017年 | 147篇 |
2016年 | 230篇 |
2015年 | 202篇 |
2014年 | 278篇 |
2013年 | 888篇 |
2012年 | 364篇 |
2011年 | 510篇 |
2010年 | 417篇 |
2009年 | 487篇 |
2008年 | 530篇 |
2007年 | 527篇 |
2006年 | 461篇 |
2005年 | 433篇 |
2004年 | 356篇 |
2003年 | 367篇 |
2002年 | 354篇 |
2001年 | 478篇 |
2000年 | 352篇 |
1999年 | 216篇 |
1998年 | 133篇 |
1997年 | 160篇 |
1996年 | 169篇 |
1995年 | 193篇 |
1994年 | 193篇 |
1993年 | 162篇 |
1992年 | 135篇 |
1991年 | 174篇 |
1990年 | 167篇 |
1989年 | 157篇 |
1988年 | 117篇 |
1987年 | 116篇 |
1986年 | 118篇 |
1985年 | 91篇 |
1984年 | 108篇 |
1983年 | 110篇 |
1982年 | 119篇 |
1981年 | 108篇 |
1980年 | 97篇 |
1979年 | 112篇 |
1978年 | 73篇 |
1977年 | 77篇 |
1975年 | 77篇 |
1973年 | 72篇 |
1967年 | 66篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
361.
Viana M Postigo C Querol X Alastuey A López de Alda MJ Barceló D Artíñano B López-Mahia P García Gacio D Cots N 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1241-1247
Levels of cocaine and other psychoactive substances in atmospheric particulate matter (PM) were determined in urban environments representing distinct social behaviours with regard to drug abuse: night-life, university and residential areas. Three cities (with population >1 million and <0.3 million inhabitants) were selected. Mean daily levels of drugs in PM were 11-336 pg/m3 for cocaine, 23-34 pg/m3 for cannabinoids, and 5-90 pg/m3 for heroin. The highest levels were recorded on weekends, with factors with respect to weekdays of 1-3 for cocaine, 1-2 for cannabinoids and 1.1-1.7 for heroin. Higher levels were detected in the night-life areas, pointing towards consumption and trafficking as major emission sources, and possibly ruling out drug manufacture. The similarities in temporal trends at all sites suggested a city-scale transport of psychoactive substances. Correlations were detected between cocaine and amphetamine consumption (r2 = 0.98), and between heroin and cannabinoids (r2>0.82). 相似文献
362.
Amorim MJ Pereira C Menezes-Oliveira VB Campos B Soares AM Loureiro S 《Environmental pollution (Barking, Essex : 1987)》2012,160(1):145-152
Chemicals are often found in the environment as complex mixtures. There has been a large effort in the last decade to assess the combined effect of chemicals, using the conceptual models of Concentration Addition and Independent Action, but also including synergistic, antagonistic, dose-level and dose-ratio dependent deviations from these models. In the present study, single and mixture toxicity of atrazine, dimethoate, lindane, zinc and cadmium were studied in Folsomia candida, assessing survival and reproduction. Different response patterns were observed for the different endpoints and synergistic patterns were observed when pesticides were present. Compared with the previously tested Enchytraeus albidus and Porcellionides pruinosus, the mixture toxicity pattern for F. candida was species specific. The present study highlights the importance of studying toxicity of chemicals mixtures due to the observed potentiation of effects and confirms that for an adequate ecologically relevant risk assessment different organisms and endpoints should be included. 相似文献
363.
Occurrence of glyphosate and acidic herbicides in select urban rivers and streams in Canada, 2007 总被引:1,自引:1,他引:1
364.
Ishtiyaq Ahmed Najar Anisa B. Khan 《Environmental science and pollution research international》2013,20(9):6406-6417
In the present study, potential of Eisenia fetida to recycle the different types of fresh water weeds (macrophytes) used as substrate in different reactors (Azolla pinnata reactor, Trapa natans reactor, Ceratophyllum demersum reactor, free-floating macrophytes mixture reactor, and submerged macrophytes mixture reactor) during 2 months experiment is investigated. E. fetida showed significant variation in number and weight among the reactors and during the different fortnights (P <0.05) with maximum in A. pinnata reactor (number 343.3?±?10.23 %; weight 98.62?±?4.23 % ) and minimum in submerged macrophytes mixture reactor (number 105?±?5.77 %; weight 41.07?±?3.97 % ). ANOVA showed significant variation in cocoon production (F4?=?15.67, P <0.05) and mean body weight (F4?=?13.49, P <0.05) among different reactors whereas growth rate (F3?=?23.62, P <0.05) and relative growth rate (F3?=?4.91, P <0.05) exhibited significant variation during different fortnights. Reactors showed significant variation (P <0.05) in pH, Electrical conductivity (EC), Organic carbon (OC), Organic nitrogen (ON), and C/N ratio during different fortnights with increase in pH, EC, N, and K whereas decrease in OC and C/N ratio. Hierarchical cluster analysis grouped five substrates (weeds) into three clusters—poor vermicompost substrates, moderate vermicompost substrate, and excellent vermicompost substrate. Two principal components (PCs) have been identified by factor analysis with a cumulative variance of 90.43 %. PC1 accounts for 47.17 % of the total variance represents “reproduction factor” and PC2 explaining 43.26 % variance representing “growth factor.” Thus, the nature of macrophyte affects the growth and reproduction pattern of E. fetida among the different reactors, further the addition of A. pinnata in other macrophytes reactors can improve their recycling by E. fetida. 相似文献
365.
B. A. Brodovicz Jr. V. H. Sussman G. B. Murdock 《Journal of the Air & Waste Management Association (1995)》2013,63(7):484-489
The Pennsylvania Air Pollution Commission has developed a regulatory program based upon the control of local air pollution problems and reduction of pollutant levels in air basins. The geographical boundaries of 10 air basins have been established. The Commission’s air basin regulations will provide for the reduction of over-all pollutant levels and for emergency procedures in the event of adverse meteorological conditions. The paper discusses the format and objectives of the program. In order to effectively enforce the air basin regulations and maintain the necessary surveillance of the state’s air quality, a "computerized real time on-line integrated air monitoring-data handling system" has been designed. The system will incorporate a network to constantly monitor the air in each air basin.The primary objectives of the system are: 1. Constant surveillance of air pollution in the air basins. 2. Provide information on air pollution potential alerts. 3. Aid in further development of air quality criteria and regulations. The air monitoring network is estimated to include approximately 25 remote stations. Each remote will contain air pollution and meteorological sampling equipment and hardware to telemeter to a central station. The data will be transmitted over leased telephone lines. The central station in Harrisburg will contain the necessary hardware to receive and process data, calculate and display results and permit supervisory control of the network. Output options will include immediate display of edited data, command and alarm information, and presentation of statistical results. Although the air monitoring system is one of the principle ingredients of the program, the air basin concept encompasses other component systems designed to knit together the entire air pollution control program in Pennsylvania. 相似文献
366.
367.
Walter W. Kovalick Jr. Jerri P. Town Mary B. Deardorff 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1478-1485
Headquarters managers and Regional staff in the U.S. Environmental Protection Agency’s hazardous and solid waste programs were surveyed to determine priorities for technical information and guidance among EPA Regional staff, state hazardous waste management staff, EPA contractors, and the regulated community. The survey also examined delivery systems effective for EPA Regional staff. The fifteen highest ranked technical needs for RCRA, Superfund, and UST reflect a pervasive interest in hazardous waste remediation. Top priority technical needs focus on establishing cleanup levels, subsurface fate and transport, field monitoring and quality assurance, remedy selection, and most importantly, which remedies work and which do not in specific situations. Technical needs of non- EPA audiences are quite similar to those for EPA field staff. Preferences for technology transfer delivery systems are generally for conventional distribution methods (such as print materials and workshops) rather than electronic or video media. Regional staff report serious problems in utilizing technology transfer because of time constraints, insufficient knowledge of available products, insufficient travel funds, and limited access to and training on computers. 相似文献
368.
Pan B Liu WX Shi Z Cao J Shen WR Qing BP Sun R Tao S 《Journal of environmental science and health. Part. B》2004,39(3):353-365
The methods of sample purification for determinations of organochlorine pesticides (OCPs) in sediment and fish muscle were investigated in this study. A two-step procedure with preliminary cleanup and florisil column fraction was adopted. The working conditions of florisil column were firstly optimized. As to preliminary cleanup, liquid-liquid extraction by mixture of dimethyl formamide (DMF) and hexane and sulphonation by concentrated sulfuric acid were applied respectively and compared for the studied samples. The results indicated that liquid-liquid distribution could effectively separate lipids from fish muscle extracts, while failed in elimination of chlorophyll extracted from the relicts of hydrophytes in the sediment sample. In view of the sample appearance and clarity of gas chromatogram, sulphonation was more suitable to purify the sediment sample, however, the recoveries of the spiked standards were poor. The use of eluting solvent with stronger polarity could improve the corresponding recoveries significantly. Due to complete loss of Dieldrin, Endrin, and Endrin aldehyde after sulphonation, this pretreatment was improper to the three components. Sulfur, as the particular disturbing element in sediment, could be removed sufficiently by addition of activated copper powder. The relevant detection limits of the selected methods for OCPs in the studied substrates were also provided. 相似文献
369.
Alteration in uptake and translocation of essential nutrients in cabbage by excess lead 总被引:1,自引:0,他引:1
To observe the tolerance limit of lead phytotoxicity in cabbage (Brassica oleracea L.) var. Golden Aker plants were grown in refined sand with complete nutrient solution for 41 days. On 42nd day, pots with plants were separated into six lots. One lot was allowed to grow as such and was treated as control, in rest of the five lots, lead was applied at 0.1, 0.2, 0.4, 0.5 and 1.0 mM as lead nitrate. At d 75 (34 days after metal exposure), the lead toxicity symptoms as restricted growth was observed on plants at 1.0 mM lead supply. Excess lead (0.5 and 1.0 mM) developed interveinal chlorosis along the margins of young leaves. The affected leaves were reduced in size giving plant a rosette like appearance. Head size was markedly reduced at these (0.5 and 1.0 mM) levels of lead. At 0.5 mM the intensity of symptoms was markedly low. With an increase in lead supply, the concentration of lead and zinc was increased whereas that of P, S, Fe, Mn and Cu were decreased in various parts of cabbage. At 1.0 mM Pb, the concentration of lead was highest in roots and lowest in head. In leaves of cabbage the threshold of toxicity and toxicity values were 150 and 320 microg g-1 dry matter, respectively. 相似文献
370.