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951.
EPA's “Third Symposium on Fabric Filters for Particle Collection,” held in Tucson December 5 and 6, 1977, emphasized the results obtained from both laboratory and field experience. Data from selected new and/or continuing research programs as well as from new pilot and field applications are reviewed. 相似文献
952.
953.
Howard Moore Kathryn R. Williams 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1043-1045
The techniques of Principal Component Analysis (PCA) and subsequent regression analysis were used in an attempt to describe local and upwind chemical and physical factors which affect the variability of SO4 –2 concentrations observed in a rural area of the northeastern U.S. The data used in the analyses included upwind and local O3 concentrations, temperature, relative humidity and other climatological information, SO2, and meteorological information associated with backward trajectories. The investigation identified five principal components, three major (eigenvalues >1) and two minor (eigenvalues < one), which accounted for 52% (r = 0.72) of the variability in the SO4 –2 regression model. These components can be described as representing local and upwind photochemistry, droplet growth, SO2 emissions, and air mass characteristics. The study also indicated that in future studies it will be necessary to a priori select air pollution and meteorological variables for measurement to potentially increase the sensitivity of this type of receptor model. 相似文献
954.
Brian P. Leaderer Theodore R. Holford Jan A. J. Stolwijk 《Journal of the Air & Waste Management Association (1995)》2013,63(2):154-157
A PM10 monitoring network was established throughout the South Coast Air Basin (SOCAB) in the greater Los Angeles region during the calendar year 1986. Annual average PM10 mass concentrations within the Los Angeles metropolitan area ranged from 47.0 µg m-3 along the coast to 87.4 µg m-3 at Rubldoux, the furthest inland monitoring station. Measurements made at San Nicolas Island suggest that regional background aerosol contributes between 28 to 44 percent of the PM10 aerosol at monitoring sites In the SOCAB over the long term average. Five major aerosol components (carbonaceous material, NO- 3, SO= 4, NH+ 4, and soil-related material) account for greater than 80 percent of the annual average PM10 mass at all on-land monitoring stations. Peak 24-h average mass concentrations of nearly 300 µg m-3 were observed at inland locations, with lower peak values (?130–150 µg m-3) measured along the coast. Peak-day aerosol composition was characterized by increased NO- 3 Ion and associated ammonium ion levels, as compared to the annual average. There appears to be only a weak dependence of PM10 mass concentration on season of the year. This lack of a pronounced seasonal dependence results from the complex and contradictory seasonal variations in the major chemical components (carbonaceous material, nitrate, sulfate, ammonium ion and crustal material). At most sites within the Los Angeles metropolitan area, PM10 mass concentrations exceeded both the annual and 24-h average federal and state of California PM10 regulatory standards. 相似文献
955.
S.H. Cadle R.L. Williams 《Journal of the Air & Waste Management Association (1995)》2013,63(5):502-507
This paper is directed to air pollution scientists interested in special mobile emission sources. The purpose was to determine the contribution which automobile tires make to air pollution. The gaseous hydrocarbon and sulfur compounds emitted in laboratory tests were identified. Although these hydrocarbons can participate in smog reactions, their mass emission rate is less than 0.1 % of the current exhaust hydrocarbon emission rate. Hydrocarbons from tires are not measurable near a freeway. The particulate emitted from tires ranges in size from 0.01 μm to more than 30 μm, with the larger particles dominating the total mass. Measurements along a California freeway showed that most of the tire debris had settled within 5 m of the pavement edge. Airborne rubber concentrations were less than 0.5 μg/m3, or less than 5% of the total tire wear. These field measurements confirm the indoor emission pattern and verify that tire wear products are not a significant air pollution problem. 相似文献
956.
E. E. A. Rouillard R.E. Hicks 《Journal of the Air & Waste Management Association (1995)》2013,63(6):599-601
In isokinetic sampling from a gas stream it is usually assumed that the flow pattern upstream of the sampling probe is not affected by the presence of the probe. That some probes do seriously affect the gas streamlines is shown by velocity traverses taken with a hot wire anemometer under controlled flow conditions in a wind tunnel. The degree to v/hich the streamlines are affected depends on the wall thickness and taper of the nozzle, the stem diameter, as well as on the size and proximity of sampling accessories in the vicinity of the nozzle. For a probe to cause negligible disturbance under isokinetic conditions it should have a sharp-edged nozzle with little or no outside bevel, and the stem of the probe should be at least 11 stem diameters downstream from the nozzle inlet. 相似文献
957.
Louis Theodore Joseph P. Reynolds 《Journal of the Air & Waste Management Association (1995)》2013,63(7):777-779
This paper is directed to those individuals involved in design of electrostatic precipitators. The Deutsch-Anderson model is usually employed by industry for the design of electrostatic precipitators. The so-called process design variable in this approach is the total capture area in the precipitator. Unfortunately, little is available on the equipment design of this unit, i.e., the geometric arrangement of the plates that constitute the capture area and the external dimensions of the physical structure that houses the precipitator components. These are important economic considerations, and it is to this subject that this paper is directed. It is relatively easy to predict equipment costs for “off-the-shelf” electrostatic precipitators; it is more difficult to closely predict the cost for a custom-made unit, which is more often the case encountered in practice. Once the capture area is calculated, the total precipitator cost becomes a strong function of the outer casing and outer accessories of the physical system. In this paper, a model is presented that can help minimize precipitator cost. An illustrative example complements the development of the model. 相似文献
958.
959.
Bernd R. T. Simoneit M. A. Mazurek T. A. Cahill 《Journal of the Air & Waste Management Association (1995)》2013,63(4):387-390
The atmosphere of the Lake Tahoe air basin is contaminated with high molecular weight (> C12) petroleum hydrocarbons. Aerosol samples were collected by high-volume filtration and the solvent-soluble organic matter was analyzed. The relative concentrations of petroleum residues found were as follows: winter > summer and day > night. This contamination is primarily due to the poorer combustion of diesel and home heating fuels at that altitude and during periods of colder climate. 相似文献
960.