全文获取类型
收费全文 | 775篇 |
免费 | 9篇 |
国内免费 | 13篇 |
专业分类
安全科学 | 37篇 |
废物处理 | 41篇 |
环保管理 | 214篇 |
综合类 | 83篇 |
基础理论 | 160篇 |
污染及防治 | 182篇 |
评价与监测 | 51篇 |
社会与环境 | 28篇 |
灾害及防治 | 1篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 10篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 16篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 94篇 |
2012年 | 19篇 |
2011年 | 45篇 |
2010年 | 24篇 |
2009年 | 35篇 |
2008年 | 44篇 |
2007年 | 46篇 |
2006年 | 47篇 |
2005年 | 17篇 |
2004年 | 20篇 |
2003年 | 36篇 |
2002年 | 28篇 |
2001年 | 16篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 15篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 18篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1974年 | 7篇 |
1973年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有797条查询结果,搜索用时 15 毫秒
51.
52.
Environmental site assessment criteria were originally developed by organizations that focused, almost exclusively, on surface,
subsurface, and pollution source contamination. Many of the hazards associated with indoor environments and building structures
were traditionally not considered when evaluating sources and entities of environmental pollution. Since a large number of
building materials are potentially hazardous, careful evaluation is necessary. Until recently, little information on building
inspection requirements of environmental problems has been published. Traditionally, asbestos has been the main component
of concern. The ever-changing environmental standards have dramatically expanded the scope of building surveys. Indoor environmental
concerns, for example, currently include formaldehyde, lead-based paint, polychlorinated biphenyls, radon, and indoor air
pollution. Environmental regulations are being expanded and developed that specifically include building structures. These
regulatory standards are being triggered by an increased awareness of health effects from indoor exposure, fires, spills,
and other accidents that have resulted in injury, death, and financial loss. This article discusses various aspects of assessments
for building structures. 相似文献
53.
Kenneth M. Karch 《环境质量管理》1994,3(3):297-307
Benchmarking is a process companies use to identify and evaluate the best practices, both inside and outside their industry, in their field of interest. The goal is to identify gaps between their performance and the benchmarks so that they can find ways to improve their performance. This article describes an early benchmarking effort in the environmental management area of the Weyerhaeuser Company. 相似文献
54.
Kenneth G. Maxey Norman H. Starler 《Journal of the American Water Resources Association》1987,23(5):749-759
ABSTRACT: In the past, development of Federal water resource projects depended heavily or exclusively on Federal financing of construction costs. However, pressures on the Federal budget, environmental issues, and the notion that there are economic efficiency gains when beneficiaries of Federal water resource projects increase their cost share are causing changes. The case of the Central Arizona Project Plan 6 is a noteworthy example of the transition to more non-Federal participation in water resource development. This is because the non-Federal financing is to be provided for a project already under construction. The negotiation and terms of the Plan 6 financing agreement between the Department of the Interior and multiple interests in Arizona are used as an example of how Federal water project cost sharing is in a state of transition. The negotiation process is described, a financial analysis is provided, and the terms of the agreement and policy issues that were deliberated in the Executive Branch of the Federal Government are discussed. 相似文献
55.
Fred J. Brenner William Kanour Bruce Weston Gerald Valerio Kenneth R. Grayburn 《Environmental management》1986,10(2):241-253
A study of the impact of two flood control reservoirs and pollution influx was conducted on two streams within the Sandy Creek Watershed, Mercer County, Pennsylvania, USA. Fecal coliforms were significantly reduced in the outflows without affecting water chemistry, thereby improving the overall water quality. The size and composition of the aquatic communities as well as stream metabolism varied seasonably among the different sampling stations. Pollution influx primarily from communities and agricultural drainage had a greater impact on the stream ecosystem than did impounding of the streams. Natural wetlands and riparian vegetation were important factors in reducing the pollution load in these streams. The reestablishment and maintenance of riparian vegetation should therefore be an integral part of the land-use plan for watersheds in order to improve water quality and wildlife habitats. In the future, the maintenance of riparian vegetation should be given prime consideration in the development of watershed projects. 相似文献
56.
Martin H. David Erhard F. Joeres Eric D. Loucks Kenneth W. Potter Stuart S. Rosenthal 《Journal of the American Water Resources Association》1988,24(1):141-148
ABSTRACT: Water level fluctuations of the Great Lakes often have created regional controversies among the states and Canadian provinces that share this vast resource. Even though the 100-year range of their water levels is only four to five feet, episodes of high and low Great Lakes water levels have been a recurring problem throughout the twentieth century. The possibility of increased diversion and consumptive use has exacerbated the existing conflicts over how to manage this water resource. A research project evaluated the effects of interbasin diversion on the Great Lakes system and on the industries that depend on the maintenance of historical water levels, namely hydropower and commercial navigation. The simulation approach employed in this research and some of the important findings are presented. The approach is similar to that used in recent government studies of Great Lakes water level regulation. Several significant modifications were made specifically addressing the diversion issue. Aggregate annual impacts to hydropower and shipping resulting from a diversion of 10,000 cubic feet per second were found to vary from 60 to 100 million dollars. Increases in impacts as a function of diversion rate are nonlinear for the navigation industry. 相似文献
57.
Kenneth H. Reckhow 《Journal of the American Water Resources Association》1988,24(4):723-734
ABSTRACT: A cross-sectional data set of 80 lakes and reservoirs in nine southeastern states was examined to specify and parameterize trophic state relationships. The relationships fitted are based on measurements of several limnological variables taken over the course of a growing season or year in each of the lakes. The trophic state models relate phosphorus and nitrogen loading to inlake phosphorus and nitrogen concentrations, which in turn are related to maximum chlorophyll level, Secchi disk depth, dominant algal species, and hypolimnetic dissolved oxygen status. Due to the empirical nature of the study, causal conclusions are limited; rather, the models are most useful for prediction of average growing season conditions related to trophic state. 相似文献
58.
Mary H. Nichols Kenneth G. Renard Herbert B. Osborn 《Journal of the American Water Resources Association》2002,38(1):161-172
ABSTRACT: The climate of Southern Arizona is dominated by summer precipitation, which accounts for over 60 percent of the annual total. Summer and non‐summer precipitation data from the USDA‐ARS Walnut Gulch Experimental Watershed are analyzed to identify trends in precipitation characteristics from 1956 to 1996. During this period, annual precipitation increased. The annual precipitation increase can be attributed to an increase in precipitation during non‐summer months, and is paralleled by an increase in the proportion of annual precipitation contributed during non‐summer months. This finding is consistent with previously reported increases in non‐summer precipitation in the southwestern United States. Detailed event data were analyzed to provide insight into the characteristics of precipitation events during this time period. Precipitation event data were characterized based on the number of events, event precipitation amount, 30‐minute event intensity, and event duration. The trend in non‐summer precipitation appears to be a result of increased event frequency since the number of events increased during nonsummer months, although the average amount per event, average event intensity, and average event duration did not. During the summer “monsoon” season, the frequency of recorded precipitation events increased but the average precipitation amount per event decreased. Knowledge of precipitation trends and the characteristics of events that make up a precipitation time series is a critical first step in understanding and managing water resources in semiarid ecosystems. 相似文献
59.
Environmental regulations governing industrial activities in tundra environments stem largely from the expected ecological
effects of the activities. One of the major ecological effects of industrial activities is the surface subsidence associated
with thermokarst, which can result in changes in primary and secondary production. The primary production changes associated
with thermokarst are strongly governed by three ecosystem properties—soil temperature, water regime, and nutrient availability.
Most disturbances set in motion a more-or-less predictable sequence of landscape change related to these properties: soil
warming, thermokarst, surface flooding, accelerated organic matter decomposition, and increased nutrient availability. The
warmed soil and the enhanced nutrient availability typically lead to increased annual primary production, increased dominance
by graminoids, and reduced plant species diversity. These vegetational changes may in turn potentially enhance secondary production,
but in general these second-level responses have yet to be quantified. More information is needed about the food-chain effects
of tundra landscape disturbances before regulators can make well-informed predictions of impacts or plan useful habitat rehabilitation. 相似文献
60.
Kenneth C. Jurgens 《Journal of the American Water Resources Association》1971,7(2):260-264
.Fish and wildlife enhancement through water resources development implies fish and wildlife will be enhanced or benefit directly from such development. As a matter of practicality, the opposite may be the case in that wildlife lands of prime value and stream fisheries are often lost or severely altered as a result of reservoir construction or stream channelization. Additionally, estuarine fish and wildlife can also suffer from water resources development due to reductions in volume of fresh waters reaching the estuaries and adjacent marshes. In some instances waterfowl habitat can be created by reservoir construction and with good planning waterfowl habitat and use may be enhanced. To offset losses of thousands of acres of wildlife habitat when a river system is to be totally harnessed, planners could set aside sufficiently large natural areas dedicated for use by wildlife. This, however, would be replacement rather than enhancement. Reservoir fisheries can be enhanced with good planning to include timber clearing, shoreline clearing, boat road clearing, variable level drawoff devices and tailrace escapement channels. To sum up, it is possible for some species offish and wildlife to be enhanced through water resources development but only at the expense of others, and then only through careful and integrated planning. 相似文献