全文获取类型
收费全文 | 19292篇 |
免费 | 245篇 |
国内免费 | 175篇 |
专业分类
安全科学 | 607篇 |
废物处理 | 806篇 |
环保管理 | 2554篇 |
综合类 | 3034篇 |
基础理论 | 5226篇 |
环境理论 | 7篇 |
污染及防治 | 4885篇 |
评价与监测 | 1344篇 |
社会与环境 | 1118篇 |
灾害及防治 | 131篇 |
出版年
2022年 | 161篇 |
2021年 | 147篇 |
2020年 | 153篇 |
2019年 | 167篇 |
2018年 | 280篇 |
2017年 | 341篇 |
2016年 | 453篇 |
2015年 | 368篇 |
2014年 | 576篇 |
2013年 | 1511篇 |
2012年 | 665篇 |
2011年 | 904篇 |
2010年 | 776篇 |
2009年 | 764篇 |
2008年 | 865篇 |
2007年 | 916篇 |
2006年 | 775篇 |
2005年 | 674篇 |
2004年 | 664篇 |
2003年 | 639篇 |
2002年 | 621篇 |
2001年 | 737篇 |
2000年 | 540篇 |
1999年 | 313篇 |
1998年 | 220篇 |
1997年 | 266篇 |
1996年 | 252篇 |
1995年 | 287篇 |
1994年 | 288篇 |
1993年 | 223篇 |
1992年 | 234篇 |
1991年 | 213篇 |
1990年 | 232篇 |
1989年 | 211篇 |
1988年 | 169篇 |
1987年 | 177篇 |
1986年 | 170篇 |
1985年 | 178篇 |
1984年 | 166篇 |
1983年 | 166篇 |
1982年 | 146篇 |
1981年 | 150篇 |
1980年 | 136篇 |
1979年 | 141篇 |
1978年 | 113篇 |
1977年 | 116篇 |
1975年 | 92篇 |
1974年 | 90篇 |
1973年 | 98篇 |
1972年 | 91篇 |
排序方式: 共有10000条查询结果,搜索用时 781 毫秒
901.
David Leith Michael J. Ellenbecker 《Journal of the Air & Waste Management Association (1995)》2013,63(8):877-881
Presently, there is no effective way to interpret or predict dust penetration through a pulse-jet cleaned fabric filter. This paper presents a model which considers penetration straight through the filter and penetration by seepage. A considerable number of studies have been devoted to penetration by the straight through process; however, a comparison of data from the literature with the present model indicates that seepage and not straight through penetration accounts for virtually all penetrating dust. Although insufficient information is presently available to use the model to predict penetration, the model does show trends that should occur with changes in filter operating variables such as filtration velocity and pulse pressure, and suggests areas in which further research is necessary. 相似文献
902.
903.
Joseph P. Reynolds Louis Theodore 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1255-1257
Baghouse operation and maintenance is probably the most serious problem area of fabric filter operations. Committee TC-1 (Particulates) of the Air Pollution Control Association recently surveyed baghouse installations in'the United States for the purpose of gathering information on operation and maintenance procedures and problems. One hundred thirty-three questionnaires were completed and returned. In this paper, the results of a comprehensive analysis of these data are described and interpreted. A multiple-choice type of compilation of the responses has been used to permit statistical interpretation of the results. Due to the length of the questionnaire and the tables which resulted from the analysis, these are described but not included in the following paper. They are available from the TC-1 Committee c/o APCA. 相似文献
904.
905.
906.
G. P. Greiner D. A. Furlong D. W. VanOsdell L. S. Hovis 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1125-1130
The concept of electrostatic stimulation of fabric filtration (ESFF) has been investigated at pilot scale. The pilot unit consisted of a conventional baghouse in parallel with an ESFF baghouse, allowing direct comparison. All results reported in this paper are for pulse-cleaned bags in which the electric field was maintained parallel to the fabric surface. The performance of the ESFF baghouse has been superior to the parallel conventional baghouse by several measures. The ESFF baghouse demonstrated: (1) a reduced rate of pressure drop increase during a filtration cycle, (2) lower residual pressure drop, (3) stable operation at higher face velocities, and (4) improved particle removal efficiency. These benefits can be obtained with only minor modifications to conventional pulse-jet hardware and at low electrical power consumption. The indicated ability to operate at increased face velocities with only modest expenditure for electrical hardware leads to very favorable economic projections. 相似文献
907.
908.
Michael Duncan Hinrich L. Bohn Mark Burr 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1175-1179
If many homeowners convert to solid fuels for heating, residential flue gases will be a large source of air pollution. Control of this pollution requires an inexpensive, reliable, and effective method of flue gas treatment. One such method is to force flue gases through soil beds. Such soil treatment removes all detectable smoke, odor, and polynuclear organic matter (POM), up to 97% of the CO, and at least 97% of the SO2 from flue gases of wood and coal combustion. The technique is low cost, reliable, almost maintenance-free, and also appears suitable for other small point sources of air pollution. 相似文献
909.
Charles J. Weschler Stephen P. Kelty Joyce E. Lingousky 《Journal of the Air & Waste Management Association (1995)》2013,63(6):624-629
As part of an energy conservation program recently implemented by the Bell System, fans in many telephone equipment buildings now operate only when necessary to bring the temperature within allowable limits, rather than continuously. In the study reported here the effects of fan operation on indoor-outdoor dust relationships were monitored at 2 representative telephone offices. Automatic dichotomous samplers were used to collect fine and coarse aerosol particles inside telephone equipment buildings at Wichita, KS and Lubbock, TX. At both sites, outdoor samples (roof top) were collected at the same time as the indoor samples. During the tests the building fans were repetitively cycled between 2-week intervals of continuous fan operation and 2-week intervals of intermittent fan operation. The indoor dust concentrations typically increased when the fans were off. The results indicate that this increase was due to loss of constant filtration, but not due to loss of building pressurlzation (i.e., filtration of the recirculated air is largely responsible for the lower dust levels when the fans are running continuously). An expression is derived for the relative dust increase when the building fans are switched off. Among other factors, the relative increase is directly proportional to the efficiency of the building filters and to the rate at which air is recirculated through them. The present findings can be extended to similar buildings. 相似文献
910.
Lawrence P. Hanrahan Henry A. Anderson Kay A. Dally Ann D. Eckmann Marty S. Kanarek 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1164-1167
Mobile homes utilize a class of prefabricate construction techniques which rely greatly upon the use of particle board and hardwood plywood paneling for structural components. This has resulted In household sources which may emit formaldehyde into the home, since urea-formaldehyde resins are used as the bonding agent in most pressed wood stocks. A series of 137 mobile home households was investigated to determine indoor formaldehyde exposure concentrations. Homes were selected based on the estimated age of the construction components. Homes were studied serially for a nine-month period, with formaldehyde samples obtained on a monthly basis using a modified NIOSH chromotropic acid procedure. Formaldehyde concentrations were found to range from less than 0.10 ppm to 2.84 ppm. The median exposure concentration was 0.39 ppm. Analysis of variance was performed on each home to discern visit and room measurement effects. Eighty-nine percent of the homes exhibited no measurement placement effects, while only 10 percent failed to demonstrate between-visit variance effects. Regression models were constructed to predict household formaldehyde concentrations. Concentrations exhibited an inverse relationship with the age of the construction materials. A weighted least squares regression model of log of home age predicting temperature-corrected log formaldehyde explained 82 percent of the formaldehyde variation. 相似文献