全文获取类型
收费全文 | 2171篇 |
免费 | 53篇 |
国内免费 | 27篇 |
专业分类
安全科学 | 84篇 |
废物处理 | 99篇 |
环保管理 | 442篇 |
综合类 | 294篇 |
基础理论 | 479篇 |
环境理论 | 3篇 |
污染及防治 | 573篇 |
评价与监测 | 165篇 |
社会与环境 | 100篇 |
灾害及防治 | 12篇 |
出版年
2023年 | 21篇 |
2022年 | 32篇 |
2021年 | 35篇 |
2020年 | 32篇 |
2019年 | 25篇 |
2018年 | 50篇 |
2017年 | 55篇 |
2016年 | 58篇 |
2015年 | 55篇 |
2014年 | 73篇 |
2013年 | 153篇 |
2012年 | 100篇 |
2011年 | 124篇 |
2010年 | 88篇 |
2009年 | 109篇 |
2008年 | 112篇 |
2007年 | 131篇 |
2006年 | 101篇 |
2005年 | 90篇 |
2004年 | 86篇 |
2003年 | 76篇 |
2002年 | 79篇 |
2001年 | 49篇 |
2000年 | 46篇 |
1999年 | 32篇 |
1998年 | 40篇 |
1997年 | 29篇 |
1996年 | 39篇 |
1995年 | 37篇 |
1994年 | 29篇 |
1993年 | 19篇 |
1992年 | 24篇 |
1991年 | 12篇 |
1990年 | 20篇 |
1989年 | 20篇 |
1988年 | 14篇 |
1987年 | 17篇 |
1986年 | 15篇 |
1985年 | 15篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 7篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1972年 | 5篇 |
1968年 | 3篇 |
排序方式: 共有2251条查询结果,搜索用时 31 毫秒
91.
Kevin G. Boggs Robert W. Van Kirk Gary S. Johnson Jerry P. Fairley P. Steve Porter 《Journal of the American Water Resources Association》2010,46(6):1116-1132
Boggs, Kevin G., Robert W. Van Kirk, Gary S. Johnson, Jerry P. Fairley, and P. Steve Porter, 2010. Analytical Solutions to the Linearized Boussinesq Equation for Assessing the Effects of Recharge on Aquifer Discharge. Journal of the American Water Resources Association (JAWRA) 46(6):1116–1132. DOI: 10.1111/j.1752-1688.2010.00479.x Abstract: There is a need to develop a general understanding of how variations in aquifer recharge are reflected in discharge. Analytical solutions to the linearized Boussinesq equation governing flow in an unconfined aquifer provide a unified mathematical framework to quantify relationships among lag time, attenuation and distance between aquifer recharge and discharge and the effect of an up-gradient no-flow boundary. We applied this framework to three types of recharge: (1) instantaneous, (2) periodic, and (3) constant rate for a finite duration. When the temporal scale of recharge exceeds the diffusive aquifer time scale, recharge will be reflected in discharge quickly and with little attenuation. When aquifer time scale is large, most recharge events are shorter in scale than that of the aquifer, resulting in large attenuation. Attenuation is more sensitive to boundary effects than lag time, and boundary effects increase as recharge time scale increases. Boundary effects can often be ignored when the recharge source is farther than 1/3 of the domain length away from the no-flow boundary. We illustrate analytical results with application to the economically critical Eastern Snake River Plain Aquifer in Idaho. In this aquifer, detectable annual and decadal cycles in discharge can result from recharge no farther than 20 and 60 km away from the discharge point, respectively. The effects of more distant, long-term recharge can be detected only after a time lag of several decades. 相似文献
92.
Although composting has been successfully used at pilot scale to manage waste algae removed from eutrophied water environments and the compost product applied as a fertiliser, clear guidelines are not available for full scale algae composting. The review reports on the application of composting to stabilize waste algae, which to date has mainly been macro-algae, and identifies the peculiarities of algae as a composting feedstock, these being: relatively low carbon to nitrogen (C/N) ratio, which can result in nitrogen loss as NH3 and even N2O; high moisture content and low porosity, which together make aeration challenging; potentially high salinity, which can have adverse consequence for composting; and potentially have high metals and toxin content, which can affect application of the product as a fertiliser. To overcome the challenges that these peculiarities impose co-compost materials can be employed. 相似文献
93.
Pietro A. Catizone Steven E. Zell Christopher R. Arrington Michael B. Newman Steven F. Weber Robert J. White 《Journal of the Air & Waste Management Association (1995)》2014,64(3):291-308
Detailed hourly precipitation data are required for long-range modeling of dispersion and wet deposition of particulate matter and water-soluble pollutants using the CALPUFF model. In sparsely populated areas such as the north central United States, ground-based precipitation measurement stations may be too widely spaced to offer a complete and accurate spatial representation of hourly precipitation within a modeling domain. The availability of remotely sensed precipitation data by satellite and the National Weather Service array of next-generation radars (NEXRAD) deployed nationally provide an opportunity to improve on the paucity of data for these areas. Before adopting a new method of precipitation estimation in a modeling protocol, it should be compared with the ground-based precipitation measurements, which are currently relied upon for modeling purposes. This paper presents a statistical comparison between hourly precipitation measurements for the years 2006 through 2008 at 25 ground-based stations in the north central United States and radar-based precipitation measurements available from the National Center for Environmental Predictions (NCEP) as Stage IV data at the nearest grid cell to each selected precipitation station. It was found that the statistical agreement between the two methods depends strongly on whether the ground-based hourly precipitation is measured to within 0.1 in/hr or to within 0.01 in/hr. The results of the statistical comparison indicate that it would be more accurate to use gridded Stage IV precipitation data in a gridded dispersion model for a long-range simulation, than to rely on precipitation data interpolated between widely scattered rain gauges.
Implications:
The current reliance on ground-based rain gauges for precipitation events and hourly data for modeling of dispersion and wet deposition of particulate matter and water-soluble pollutants results in potentially large discontinuity in data coverage and the need to extrapolate data between monitoring stations. The use of radar-based precipitation data, which is available for the entire continental United States and nearby areas, would resolve these data gaps and provide a complete and accurate spatial representation of hourly precipitation within a large modeling domain. 相似文献
94.
M. St. J. Warne G. E. Batley O. Braga J. C. Chapman D. R. Fox C. W. Hickey J. L. Stauber R. Van Dam 《Environmental science and pollution research international》2014,21(1):51-60
The Australian and New Zealand Guidelines for Fresh and Marine Water Quality are a key document in the Australian National Water Quality Management Strategy. These guidelines released in 2000 are currently being reviewed and updated. The revision is being co-ordinated by the Australian Department of Sustainability, Environment, Water, Population and Communities, while technical matters are dealt with by a series of Working Groups. The revision will be evolutionary in nature reflecting the latest scientific developments and a range of stakeholder desires. Key changes will be: increasing the types and sources of data that can be used; working collaboratively with industry to permit the use of commercial-in-confidence data; increasing the minimum data requirements; including a measure of the uncertainty of the trigger value; improving the software used to calculate trigger values; increasing the rigour of site-specific trigger values; improving the method for assessing the reliability of the trigger values; and providing guidance of measures of toxicity and toxicological endpoints that may, in the near future, be appropriate for trigger value derivation. These changes will markedly improve the number and quality of the trigger values that can be derived and will increase end-users’ ability to understand and implement the guidelines in a scientifically rigorous manner. 相似文献
95.
G. Van Houte B. Delmon J.C. Maon Ph. Dumont 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1030-1033
This publication concerns the dry removal of SO2 from gases using limestone absorbents. It reports bench-scale experiments made with commercial samples of powdered limestone (CaCO3) activated by addition of a cheap substance, namely CaCl2. The absorption was carried out in a fluidized bed traversed by the flue gases, between 600° and 900° C. The degree and rate of transformation of CaCO3 to CaSO4 in the presence of SO2 and air have been compared for unmodified and modified absorbents. Initial rates of reaction, and the variation of the rate of absorption with time have been measured. The influence of the SO2 content of the gas has been assessed. At 700° C, the maximum degree of transformation of activated limestone to sulfate exceeds 90%, whereas untreated CaCO3 transforms only to 16–20%. At the same temperature, more than 90% of SO2 contained In a gas carrying 0.35% SO2 is removed. Because of the much smaller quantity of solid absorbent required, dry absorption processes based on the modified absorbents might get renewed interest. The modified absorbents might also be used for in situ absorption in fluidized bed combustion, in which the temperatures are in the range studied in the present paper. 相似文献
96.
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
97.
Gregory A. Holton J. Steven Arendt James J. Rooney 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1202-1206
Recent catastrophic industrial accidents have left the public wary of most industrial facilities. Fearing illness and death from toxic releases, the public has opposed siting hazardous waste facilities in their locale. Associated with these concerns are fears of declining property values and a perceived reduction in the quality of life for a community. Recent political actions stemming from these fears have made siting these facilities an extremely unpopular and expensive process. This paper presents a systematic, phased approach for performing a reliability and hazards analysis of a hazardous waste facility design. It also demonstrates how the results of a risk analysis can present an accurate "risk picture" of the facility for use in alleviating public fears. A typical analysis is outlined and methods that can be used to convey to the public the results of this type of risk analysis are explored. 相似文献
98.
Robert F. Mouradiarn Steven P. Levine Hui-Qiong Ke Herbert H. Alvord 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1067-1072
Direct inlet gas chromatography (GC) is becoming one of the most frequently used techniques for measurement of volatile organics in air. Although GC is an effective tool, its usefulness as a field method can be limited by retention times of several minutes or more, and by the limits of detection. In order to address these issues, a high speed GC system featuring a capillary cold trap inlet and variable speed electrometeramplifier was developed and tested. The gas cooled inlet was used to collect and focus organic vapors from injection volumes of up to 1 ml. Resistance heating of the metal cold trap produced a narrow injection band that allowed simple separations to be completed in 5 to 20 seconds. Use of a variable speed electrometer-amplifier allowed the response time and noise suppression characteristics to be adjusted to the needs of the specific analysis. Simple mixtures of organics including aromatics, alkanes and chlorinated hydrocarbons were separated in 20 seconds or less. The limits of detection for 13 test compounds ranged from less than 1 part per billion by volume (ppbv) to about 50 ppbv. Data presented here indicate that high speed GC using a cold trap inlet may be a feasible approach for near real-time measurement of volatile organics in ambient air. 相似文献
99.
Michael G. Yost Ram A. Hashmonay Yi Zhou Robert Spear DooYong Park Steven Levine 《Journal of the Air & Waste Management Association (1995)》2013,63(4):424-433
ABSTRACT Researchers have applied open path optical sensing techniques to a variety of workplace and environmental monitoring problems. Usually these data are reported in terms of a path-average (or path-integrated) concentration. When assessing potential human exposures along a beam path, this path-average value is not always informative, since concentrations along the path can vary substantially from the beam average. The focus of this research is to arrive at a method for estimating the upper-bound in contaminant concentrations over a fixed open beam path. The approach taken here uses a statistical model to estimate an upper-bound concentration based on a combination of the path-average and a measure of the spatial variability computed from point samples along the beam path. Results of computer simulations and experimental testing in a controlled ventilation chamber indicate that the model produced conservative estimates for the maximum concentration along the beam path. This approach may have many applications for open path monitoring in workplaces or wherever maximum concentrations are a concern. 相似文献
100.