全文获取类型
收费全文 | 42573篇 |
免费 | 461篇 |
国内免费 | 588篇 |
专业分类
安全科学 | 1356篇 |
废物处理 | 1911篇 |
环保管理 | 5541篇 |
综合类 | 6665篇 |
基础理论 | 11314篇 |
环境理论 | 21篇 |
污染及防治 | 11413篇 |
评价与监测 | 2830篇 |
社会与环境 | 2291篇 |
灾害及防治 | 280篇 |
出版年
2023年 | 183篇 |
2022年 | 408篇 |
2021年 | 415篇 |
2020年 | 311篇 |
2019年 | 382篇 |
2018年 | 642篇 |
2017年 | 635篇 |
2016年 | 999篇 |
2015年 | 790篇 |
2014年 | 1203篇 |
2013年 | 3511篇 |
2012年 | 1445篇 |
2011年 | 1918篇 |
2010年 | 1572篇 |
2009年 | 1652篇 |
2008年 | 1957篇 |
2007年 | 2028篇 |
2006年 | 1756篇 |
2005年 | 1472篇 |
2004年 | 1405篇 |
2003年 | 1494篇 |
2002年 | 1350篇 |
2001年 | 1708篇 |
2000年 | 1214篇 |
1999年 | 728篇 |
1998年 | 521篇 |
1997年 | 513篇 |
1996年 | 551篇 |
1995年 | 614篇 |
1994年 | 609篇 |
1993年 | 520篇 |
1992年 | 517篇 |
1991年 | 480篇 |
1990年 | 532篇 |
1989年 | 462篇 |
1988年 | 418篇 |
1987年 | 394篇 |
1986年 | 335篇 |
1985年 | 356篇 |
1984年 | 394篇 |
1983年 | 383篇 |
1982年 | 370篇 |
1981年 | 352篇 |
1980年 | 284篇 |
1979年 | 321篇 |
1978年 | 269篇 |
1977年 | 201篇 |
1975年 | 215篇 |
1972年 | 212篇 |
1971年 | 186篇 |
排序方式: 共有10000条查询结果,搜索用时 468 毫秒
911.
The article details the development and uses of the water poverty index (WPI). The index was developed as a holistic tool to measure water stress at the household and community levels, designed to aid national decision makers, at community and central government level, as well as donor agencies, to determine priority needs for interventions in the water sector. The index combines into a single number a cluster of data directly and indirectly relevant to water stress. Subcomponents of the index include measures of: access to water; water quantity, quality and variability; water uses (domestic, food, productive purposes); capacity for water management; and environmental aspects.
The WPI methodology was developed through pilot projects in South Africa, Tanzania and Sri Lanka and involved intensive participation and consultation with all stakeholders, including water users, politicians, water sector professionals, aid agency personnel and others. The article discusses approaches for the further implementation of the water poverty index, including the possibilities of acquiring the necessary data through existing national surveys or by establishing interdisciplinary water modules in school curricula. The article argues that the WPI fills the need for a simple, open and transparent tool, one that will appeal to politicians and decision makers, and at the same time can empower poor people to participate in the better targeting of water sector interventions and development budgets in general. 相似文献
The WPI methodology was developed through pilot projects in South Africa, Tanzania and Sri Lanka and involved intensive participation and consultation with all stakeholders, including water users, politicians, water sector professionals, aid agency personnel and others. The article discusses approaches for the further implementation of the water poverty index, including the possibilities of acquiring the necessary data through existing national surveys or by establishing interdisciplinary water modules in school curricula. The article argues that the WPI fills the need for a simple, open and transparent tool, one that will appeal to politicians and decision makers, and at the same time can empower poor people to participate in the better targeting of water sector interventions and development budgets in general. 相似文献
912.
Strategies for sustainable development of the small-scale gold and diamond mining industry of Ghana 总被引:1,自引:0,他引:1
The small-scale gold and diamonds mining industry is of great importance to Ghana. Since its regularization in 1989 the sector has produced and sold over 1.5 million troy ounces of gold and 8.0 million carats of diamonds. During the same period the sector also provided direct employment to over 100,000 people and improved the socioeconomic life of many individuals and communities. However, these were largely achieved at a cost to the environment in areas where mining is carried out and there is the need to develop the industry in a sustainable manner. This paper looks at the developments in the small-scale gold and diamonds mining industry in Ghana and proposes some strategies on how the concepts of sustainable development could be applied to the industry. 相似文献
913.
This paper provides non-hazardous solid waste audit procedures and bench mark audit data for golf courses (GCs). The paper also demonstrates the narrow scope of solid waste audit data, and the need to move towards a broader auditing scope such as that contained in sustainability auditing frameworks. A case study of Clear Lake Golf Course, located in southwestern Manitoba, Canada was completed. Annual waste generation rates at the GC were estimated to be 46.2 tonnes/year with 83% of this material compostable. Grass clipping material generated from the putting greens accounted for 79% of the waste stream. The GC achieved a solid waste diversion rate of 81% (waste generated not destined for landfill per total waste material generated). A future, realistic target of 97% diversion was also identified. The 7 day audit period was found to be unsuitable for estimating grass clipping generation rates. Implementation of a broader sustainability framework for future audits will harmonize many existing management functions such as solid waste auditing, waste characterizations, pollution prevention, green procurement, customer satisfaction, and the efficiency of the operations. 相似文献
914.
ABSTRACT: The time to hydrograph peak of a watershed basin has been found to correlate with various statistical attributes (e.g., skewness and kurtosis) of its hypsometric curve (treated as probability distribution). This paper presents a theoretical travel time that is conceptually analogous to the time to hydrograph peak and can be calculated directly from the hypsometric curve of a watershed basin based on gravity and acceleration. The theoretical travel times for 23 selected watersheds in the United States are found to correlate significantly with their corresponding hypsometric attributes. In addition, the theoretical travel times are consistent with the times of concentration estimated from the Federal Aviation Administration method. Thus, this paper offers a simple theoretical explanation to the empirically identified linkage between time to hydrograph peak and hypsometric attributes. This theoretical travel time can provide an alternative way of characterizing the effects of basin morphometry on hydrologic response. 相似文献
915.
Gerard McMahon Jerad D. Bales James F. Coles Elise M. P. Giddings Humbert Zappia 《Journal of the American Water Resources Association》2003,39(6):1529-1546
ABSTRACT: This paper presents the results of a study on the use of continuous stage data to describe the relation between urban development and three aspects of hydrologic condition that are thought to influence stream ecosystems—overall stage variability, stream flashiness, and the duration of extreme‐stage conditions. This relation is examined using data from more than 70 watersheds in three contrasting environmental settings—the humid Northeast (the metropolitan Boston, Massachusetts, area); the very humid Southeast (the metropolitan Birmingham, Alabama, area); and the semiarid West (the metropolitan Salt Lake City, Utah, area). Results from the Birmingham and Boston studies provide evidence linking increased urbanization with stream flashiness. Fragmentation of developed land cover patches appears to ameliorate the effects of urbanization on overall variability and flashiness. There was less success in relating urbanization and streamflow conditions in the Salt Lake City study. A related investigation of six North Carolina sites with long term discharge and stage data indicated that hydrologic condition metrics developed using continuous stage data are comparable to flow based metrics, particularly for stream flashiness measures. 相似文献
916.
917.
James M. Omernik 《Journal of the American Water Resources Association》2003,39(3):563-573
ABSTRACT: The use of watersheds to conduct research on land/water relationships has expanded recently to include both extrapolation and reporting of water resource information and ecosystem management. More often than not, hydrologic units (HUs) are used for these purposes, with the implication that hydrologic units are synonymous with watersheds. Whereas true topographic watersheds are areas within which apparent surface water drains to a particular point, generally only 45 percent of all hydrologic units, regardless of their hierarchical level, meet this definition. Because the area contributing to the downstream point in many hydrologic units extends far beyond the unit boundaries, use of the hydrologic unit framework to show regional and national patterns of water quality and other environmental resources can result in incorrect and misleading illustrations. In this paper, the implications of this misuse are demonstrated using four adjacent HUs in central Texas. A more effective way of showing regional patterns in environmental resources is by using data from true watersheds representative of different ecological regions containing particular mosaics of geographical characteristics affecting differences in ecosystems and water quality. 相似文献
918.
919.
J. Y. Kim M.-C. Shin J.-R. Park K. Nam 《Journal of Material Cycles and Waste Management》2003,5(1):0055-0062
The effect of the soil solids concentration in batch tests on the measured values of the partition coefficient (K
p) of organic pollutants in landfill liner-soil material was investigated. Since this study was based on the results of batch
and column tests conducted independently, there were limitations to the conclusions derived. The organic compounds tested
were benzene, methylene chloride, toluene, trichloroethylene, and p-xylene. The results of this study showed that as soil solids concentrations increased, the measured K
p values of these organic compounds strongly decreased. The observed values of K
p stabilized when the soil solids concentration was above a certain value. Typical K
p values obtained from batch tests conducted under high soil solids concentrations were close to those obtained from column
tests. It was concluded that the K
p values of organic compounds measured under low soil solids concentrations, i.e., less than 100 g/l, may not correctly simulate
the field situation. Consequently, the values of K
p obtained with low soil solids concentrations can result in an overestimation of the retardation factor of the landfill liner
material.
Received: March 14, 2002 / Accepted: August 25, 2002 相似文献
920.
Laboratory column experiments run for up to 13 days compared air sparging of groundwater contaminated by dissolved petroleum hydrocarbons in sterile and non-sterile aquifer sediments as well as uncontaminated sediments and groundwater. Loss of dissolved BTEX compounds in the contaminated columns was very rapid, occurring through volatilisation. The majority of the dissolved total organic carbon (TOC) persisted for much longer periods however. A direct comparison between losses from sterile and non-sterile columns suggested a negligible contribution of biodegradation to the removal of TOC. This was difficult to confirm through examination of O2 utilisation because oxidation of a small amount of reduced sulphur in the aquifer materials was the dominant sink for O2. Despite this, it was possible to conclude that less than 22% of the removal of TOC was through biodegradation during the first three days of air sparging. 相似文献