全文获取类型
收费全文 | 16387篇 |
免费 | 234篇 |
国内免费 | 148篇 |
专业分类
安全科学 | 586篇 |
废物处理 | 597篇 |
环保管理 | 2775篇 |
综合类 | 2612篇 |
基础理论 | 4352篇 |
环境理论 | 14篇 |
污染及防治 | 3883篇 |
评价与监测 | 1029篇 |
社会与环境 | 782篇 |
灾害及防治 | 139篇 |
出版年
2023年 | 112篇 |
2022年 | 151篇 |
2021年 | 151篇 |
2020年 | 133篇 |
2019年 | 157篇 |
2018年 | 280篇 |
2017年 | 261篇 |
2016年 | 387篇 |
2015年 | 307篇 |
2014年 | 416篇 |
2013年 | 1259篇 |
2012年 | 572篇 |
2011年 | 769篇 |
2010年 | 596篇 |
2009年 | 698篇 |
2008年 | 757篇 |
2007年 | 750篇 |
2006年 | 655篇 |
2005年 | 598篇 |
2004年 | 515篇 |
2003年 | 499篇 |
2002年 | 478篇 |
2001年 | 552篇 |
2000年 | 432篇 |
1999年 | 275篇 |
1998年 | 203篇 |
1997年 | 210篇 |
1996年 | 220篇 |
1995年 | 261篇 |
1994年 | 260篇 |
1993年 | 221篇 |
1992年 | 183篇 |
1991年 | 203篇 |
1990年 | 196篇 |
1989年 | 192篇 |
1988年 | 144篇 |
1987年 | 147篇 |
1986年 | 154篇 |
1985年 | 129篇 |
1984年 | 149篇 |
1983年 | 152篇 |
1982年 | 167篇 |
1981年 | 147篇 |
1980年 | 126篇 |
1979年 | 125篇 |
1978年 | 101篇 |
1977年 | 91篇 |
1976年 | 74篇 |
1975年 | 83篇 |
1973年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 557 毫秒
751.
S. Witz M. Smith M. Shu A. B. Moore 《Journal of the Air & Waste Management Association (1995)》2013,63(3):276-278
Air monitoring In the San Francisco Bay Area was carried out to measure outdoor community air concentrations of poly cyclic aromatic hydrocarbons (PAH) and mutagenlc activity (mutagenlclty) In participate organic matter (POM). Monitoring began In 1979 and Is currently conducted at six stations. PAH and mutagenlclty tests were performed on organic extracts prepared from high volume (hl-vol) filters composited every four months, by meteorological season. PAH were determined by high pressure liquid chromatography (HPLC) with fluorescence and ultraviolet detection. Mutagenlclty was measured In the Ames Salmonella bloas-say using strain TA98 with and without metabolic activation. The nine-year mean concentration of benzo(a)pyrene (BaP) was 0.4 ng/m3. The mutagenlcfty of this amount of BaP accounted for only about 0.2% of the observed mutagenicity In POM and other measured PAH accounted for even less. Concentrations of PAH and mutagenlclty were three to nine times higher during the winter than during other seasons. Year-to-year wintertime trends In several PAH were also seen. Early In the 1980s, winter concentrations of BaP and benzo (g,h,i)perylene Increased. However since the mld-1980’s, their concentrations have fallen. The decrease In PAH concentrations may be the result of an Increasing proportion of vehicles with relatively low organic emissions. In contrast to PAH, mutagenlcfty did not show significant year-to-year time trends. 相似文献
752.
753.
A. R. Hawthorne R. B. Gammage 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1126-1131
An important potential source of formaldehyde in the home is ureaformaldehyde foam insulation (UFFI). This study measures the long-term release of formaldehyde through the interior wall of test panels foamed with commercial urea-formaldehyde insulation. The measurements, made approximately 16 mo after initial foaming, were conducted under both static and dynamic air conditions with air flow selected to simulate a typical air exchange found in houses. Estimated room concentrations based on a simple model of uniform mixing within a room and measured emission rates are presented. Measurements of formaldehyde in the air from within the UFFI cavities are also reported. 相似文献
754.
Warren B. Johnson 《Journal of the Air & Waste Management Association (1995)》2013,63(6):563-574
Regional scale air quality simulation models covering spatial scales of thousands of kilometers are finding increasing applications in studies of acid deposition and other air pollution problems. The purpose of this paper is to familiarize the nonexpert with the characteristics of the major types of interregional air quality models currently in use: Eulerian grid, statistical trajectory, and Lagrangian trajectory. The basic features, advantages, and disadvantages of each of these modeling approaches are summarized, as are the important limitations and problems associated with interregional modeling in general. Typical applications are illustrated using examples from the use of a representative Lagrangian trajectory model, ENAMAP, over the eastern North American area. 相似文献
755.
R.M. Adams S.A. Hamilton B. A. McCarl 《Journal of the Air & Waste Management Association (1995)》2013,63(9):938-943
Past attempts to measure the economic consequences of ozone on agriculture have been based on limited plant science information. This paper reports on an economic assessment of ozone on U.S. agriculture using recent crop response data from the National Crop Loss Assessment Network (NCLAN). The results are derived from a U.S. agricultural sector model that includes major crop and livestock production as well as domestic consumption, livestock feeding and export uses. The economic effects of four hypothetical ambient ozone levels are investigated. The analysis Indicates that the benefits to society of moderate (25%) ozone reductions are approximately $1.7 billion. A 25% Increase in ozone pollution results in costs (negative benefits) of $2.1 billion. These estimates do not reflect compliance costs of achieving the ozone changes and hence are not net benefits. 相似文献
756.
G. B. Howe R. K. M. Jayanty A. V. Rao W. F. Gutknecht C. E. Decker D. J. von Lehmden 《Journal of the Air & Waste Management Association (1995)》2013,63(9):823-826
A repository of 38 gaseous organic compounds in compressed gas cylinders has been established by EPA. This repository was established to provide standards for source test performance audits, that is, quantitative quality assurance tests. Among these compounds are ten halogenated organic species, which are the focus of this paper. Stability studies of all ten compounds have been performed to determine the feasibility of using them as performance audit standards. Results indicate that all of the halocarbons tested are adequately stable to be used as reliable audit standards. Subsequent to completion of stability studies, four of the ten halocarbons were used in source test performance audits. Results are available at this time for two of the four compounds; the results show agreement within 10% of the concentrations previously established by Research Triangle Institute. 相似文献
757.
758.
John C. S. Chang J. David Mobley 《Journal of the Air & Waste Management Association (1995)》2013,63(10):955-962
Pilot plant (0.1 MW) tests and utility boiler full scale demonstration (194 MW) of byproduct organic dibasic acids (DBA) as buffer additives to limestone scrubbers have shown performance improvements equivalent to those achieved by the addition of pure adipic acid. Both SO2 removal efficiency and limestone utilization increased, and no significant operating problems were observed with three of the four DBA tested. Chemical and biological evaluations of scrubber samples taken during the DBA testing indicated no detectable tOxicity or mutagenicity, and no significant environmental impact is expected as a result of DBA addition. Economic estimates indicate that substitution of DBA for pure adipic acid as a buffer additive will result in additive cost savings of 30 % or greater. 相似文献
759.
Myrto Petreas Kai-Shen Liu Bei-Hung Chang Steven B. Hayward Ken Sexton 《Journal of the Air & Waste Management Association (1995)》2013,63(5):647-651
As part of the California Mobile Home Study, over 250 mobile homes from throughout the state were monitored for nitrogen dioxide (NO2) concentrations. Week-long average measurements were taken with Palmes tubes in the kitchen and bedroom of each mobile home during the summer of 1984 and the winter of 1985. The study was conducted entirely by mail with the participants providing all the necessary information. Mobile homes using gas for cooking had significantly higher indoor NO2 levels than those using electricity. Mobile homes located in the Los Angeles basin had significantly higher indoor NO2 concentrations than did mobile homes in the rest of the state. Gas cooking, the inverse of the house volume and geographic location (as a surrogate of outdoor NO2) were the most important variables identified by multiple linear regression. 相似文献
760.
George R. Offen David Eskinazi Michael W. McElroy John S. Maulbetsch 《Journal of the Air & Waste Management Association (1995)》2013,63(7):864-871
From March 23rd to 26th, 1987, the city of New Orleans hosted 350 attendees, including representatives from 15 foreign countries, at the 1987 Joint Symposium on Stationary Combustion NOx Control. Cosponsored by the Electric Power Research Institute (EPRI) and the U.S. Environmental Protection Agency (EPA), the symposium provided attendees the opportunity to hear 49 papers in nine sessions covering technological and regulatory developments on NOx control in the United States and abroad since the May 1985 symposium in Boston. Session topics included general environmental issues, low-NOx combustion equipment (i.e., low-NOx burners, reburning, etc.), flue gas treatment, fundamental combustion research, and special issues for cyclone coal-fueled boilers, oil- and gas-fired boilers, and industrial combustion applications. Advances to the state-of-the-art presented at this symposium include: improved and/or newly applied combustion modifications for pulverized coal-fired boilers; further analyses of reburning, the leading combustion modification option for cyclone-equipped boilers; initial experiences with catalytic flue gas treatment in Europe; studies of NOx control retrofit options for oil- and gas-fired utility systems; and new technology developments for coal, oil, and gas fueled utility and industrial combustors. This paper summarizes those presentations that discussed significant changes since May 1985 in areas of potential interest to EPRI and its utility members. Where appropriate, they include our perspectives on the applicability of these newly disclosed findings to utility systems. 相似文献