全文获取类型
收费全文 | 15538篇 |
免费 | 158篇 |
国内免费 | 126篇 |
专业分类
安全科学 | 374篇 |
废物处理 | 666篇 |
环保管理 | 1794篇 |
综合类 | 2540篇 |
基础理论 | 4308篇 |
环境理论 | 4篇 |
污染及防治 | 4025篇 |
评价与监测 | 1056篇 |
社会与环境 | 963篇 |
灾害及防治 | 92篇 |
出版年
2022年 | 127篇 |
2021年 | 104篇 |
2020年 | 100篇 |
2019年 | 106篇 |
2018年 | 195篇 |
2017年 | 233篇 |
2016年 | 326篇 |
2015年 | 266篇 |
2014年 | 452篇 |
2013年 | 1202篇 |
2012年 | 491篇 |
2011年 | 691篇 |
2010年 | 613篇 |
2009年 | 581篇 |
2008年 | 671篇 |
2007年 | 713篇 |
2006年 | 589篇 |
2005年 | 513篇 |
2004年 | 521篇 |
2003年 | 507篇 |
2002年 | 489篇 |
2001年 | 647篇 |
2000年 | 475篇 |
1999年 | 254篇 |
1998年 | 173篇 |
1997年 | 206篇 |
1996年 | 205篇 |
1995年 | 236篇 |
1994年 | 234篇 |
1993年 | 180篇 |
1992年 | 195篇 |
1991年 | 183篇 |
1990年 | 203篇 |
1989年 | 187篇 |
1988年 | 151篇 |
1987年 | 162篇 |
1986年 | 153篇 |
1985年 | 156篇 |
1984年 | 148篇 |
1983年 | 140篇 |
1982年 | 125篇 |
1981年 | 120篇 |
1980年 | 115篇 |
1979年 | 124篇 |
1978年 | 100篇 |
1977年 | 113篇 |
1975年 | 87篇 |
1974年 | 87篇 |
1973年 | 96篇 |
1972年 | 86篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
H. P. Sanderson R. Thomas Morris Katz 《Journal of the Air & Waste Management Association (1995)》2013,63(6):328-330
Field experience with the lead acetate impregnated paper tape sampler has indicated that large errors may arise in this method due to fading of the color of the precipitated lead sulfide spots. This fading is due to the action of light, sulfur dioxide, ozone, on other substances capable of oxidizing lead sulfide. The moisture content or relative humidity of the air sample must be maintained at an appropriate level to ensure reaction with the impregnated paper tape. The effects of the factors have been investigated in laboratory experiments with known concentrations of H2S. A number of antioxidants were studied in relation to the stability of the resultant spots to light and oxidation Orthophenyl phenol was found to be the most effective antioxidant for this purpose. A number of necessary precautions to be employed in the use of the lead acetate method are recommended and the limitations are discussed. 相似文献
952.
953.
954.
P. R. Miller J. R. Parmeter Jr. Brigitta H. Flick C. W. Martinez 《Journal of the Air & Waste Management Association (1995)》2013,63(6):435-438
Photochemical oxidant injury to ponderosa pine (Pinus ponderosa Laws) is a severe problem in the southern California mountains. Three-year-old ponderosa pines fumigated in controlled environment chambers with ozone at 0.15, 0.30, or 0.45 ppm had apparent photosynthesis rates reduced by 10, 70, and 85%, respectively, after 30 days exposure. A fumigation with 0.30 ppm ozone for 33 days depressed the cold perchloric acid extracted polysaccharides of both current and one-year-old needles by 40%. The 80% ethanol soluble sugar concentration of current year, ozone-injured needles increased 16% and that of the one-year-old needles decreased slightly. Both carbohydrate fractions of control trees in carbon-filtered air increased moderately. Higher, endogenous concentrations of ascorbic acid in needles did not protect the tissue from ozone injury. Apparent photosynthesis rate was a sensitive index for ozone dosage response. Needle carbohydrate depletion probably induces premature abscission. 相似文献
955.
H.P. Schuchmann K.J. Laidler 《Journal of the Air & Waste Management Association (1995)》2013,63(1):52-53
Recent studies of organic pyrolyses in the presence of nitric oxide have shown that various nitogen compounds, such as hydrogen cyanide (HCN) and aceto-nitrile (CH3CN) are formed. This suggests the possibility that such compounds will be found in internal combustion processes, and may be present in automobile exhaust gases. The present paper describes some gas-chromatographic and wet analyses of exhaust gases. It is concluded that the amounts of hydrogen cyanide are less than 1 ppm, but that various organic nitrogen compounds may reach a level of about 100 ppm. The significance of these results is discussed. 相似文献
956.
N.C.G. Freeman T. Wainman P.J. Lioy A.H. Stern S.I. Shupack 《Journal of the Air & Waste Management Association (1995)》2013,63(8):604-605
Honorary Memberships are conferred by the Air Pollution Control Association on persons of widely recognized eminence in some part of the field of air pollution control or who have rendered especially meritorious service to the Association. Honorary Memberships were awarded this year to Dr. Leonard Greenburg and Mr. Milton Reizenstein, both past presidents of APCA. 相似文献
957.
B. R. Hubble Stanley Siegel L. H. Fuchs H. R. Hoekstra B. Tani P. T. Cunningham 《Journal of the Air & Waste Management Association (1995)》2013,63(4):343-346
Abstract Inspection and maintenance programs for motor vehicles in the United States increasingly use loaded mode mass emissions testing (IM240). A method was developed to predict mass emission rates and mass emission changes, particularly from repair benefits, using a low-cost, portable four-gas non-dispersive infrared (NDIR) vehicle exhaust gas analyzer. A single vehicle was tested several times with the analyzer while on the dynamometer and undergoing successive repairs. Excellent correlations for CO and HC were observed. Five vehicles were measured using an on-road driving loop before and after emissions-related repairs, while another three vehicles were tested with no repairs performed. The on-road concentration data used to guide the repair process were converted to grams per gallon; when divided by estimated miles per gallon, this gave grams per mile emissions for comparison to IM240. Correlation coefficients (r2) of 0.87 for CO and 0.76 for HC were achieved for the 13 tests. The linear correlations between IM240 and emissions measured by this method would allow repair facilities to perform a relatively inexpensive test for diagnostic purposes and to estimate repair effectiveness without the need for a dynamometer. 相似文献
958.
Daniel P. Y. Chang Bradford C. Grems 《Journal of the Air & Waste Management Association (1995)》2013,63(7):673-675
The body of information presented in this paper is directed toward those individuals involved with handling hazardous materials, whether in actual use of such chemicals, or in monitoring atmospheric emissions. Although specifically relating experience in the design and testing of phosgene emission control equipment, it attempts to establish general guidelines for effectively dealing with emissions of hazardous materials. An approach for handling chemical pollutants having no established air quality emission standards is developed. The paper presents a technique for establishing process emissions at acceptably low levels to insure the health and safety of the general population as well as that of the process workers themselves. Methods, suitable for measuring phosgene at these low levels, have been investigated, and problems associated with such an investigation are discussed. While complete theoretical scrubber design criteria are beyond the scope of this paper, many of the "real world" problems which affected scrubber performance are presented. Finally, the practical aspects of process emissions control are illustrated by actual results from the system test. 相似文献
959.
960.