全文获取类型
收费全文 | 10590篇 |
免费 | 1017篇 |
国内免费 | 1171篇 |
专业分类
安全科学 | 1253篇 |
废物处理 | 160篇 |
环保管理 | 2631篇 |
综合类 | 5664篇 |
基础理论 | 1025篇 |
环境理论 | 48篇 |
污染及防治 | 418篇 |
评价与监测 | 686篇 |
社会与环境 | 829篇 |
灾害及防治 | 64篇 |
出版年
2024年 | 26篇 |
2023年 | 128篇 |
2022年 | 183篇 |
2021年 | 261篇 |
2020年 | 287篇 |
2019年 | 300篇 |
2018年 | 284篇 |
2017年 | 533篇 |
2016年 | 535篇 |
2015年 | 572篇 |
2014年 | 503篇 |
2013年 | 771篇 |
2012年 | 779篇 |
2011年 | 762篇 |
2010年 | 621篇 |
2009年 | 576篇 |
2008年 | 401篇 |
2007年 | 656篇 |
2006年 | 659篇 |
2005年 | 592篇 |
2004年 | 529篇 |
2003年 | 492篇 |
2002年 | 383篇 |
2001年 | 361篇 |
2000年 | 356篇 |
1999年 | 248篇 |
1998年 | 186篇 |
1997年 | 159篇 |
1996年 | 121篇 |
1995年 | 138篇 |
1994年 | 78篇 |
1993年 | 70篇 |
1992年 | 49篇 |
1991年 | 28篇 |
1990年 | 23篇 |
1989年 | 17篇 |
1988年 | 15篇 |
1986年 | 7篇 |
1984年 | 7篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
961.
962.
为确保炼油厂设备安全而稳定地运行,各生产装置都要定期进行停工检修,在此期间排放的污染物对环境将产生一定的影响。停工检修中的环保工作包括实施环保措施;加强环境管理;并且将2000m~3隔油池由一间式变为两间式,提高污水处理率和达标率。 相似文献
963.
In many locations, regulatory agencies do not permit tree planting above landfills that are sealed with a capping clay, because
roots might penetrate the clay barrier and expose landfill contents to leaching. We find, however, no empirical or theoretical
basis for this restriction, and instead hypothesize that plant roots of any kind are incapable of penetrating the dense clays
used to seal landfills. As a test, we excavated 30 trees and shrubs, of 12 species, growing over a clay-lined municipal sanitary
landfill on Staten Island, New York. The landfill had been closed for seven years, and featured a very shallow (10 to 30-cm)
soil layer over a 45-cm layer of compacted grey marl (Woodbury series) clay. The test plants had invaded naturally from nearby
forests. All plants examined—including trees as tall as 6 m—had extremely shallow root plates, with deformed tap roots that
grew entirely above and parallel to the clay layer. Only occasional stubby feeder roots were found in the top 1 cm of clay,
and in clay cracks at depths to 6 cm, indicating that the primary impediment to root growth was physical, although both clay
and the overlying soil were highly acidic. These results, if confirmed by experimental research should lead to increased options
for the end use of many closed sanitary landfills. 相似文献
964.
Julia Badal Graf 《Journal of the American Water Resources Association》1995,31(2):265-281
ABSTRACT: The effect of unsteadiness of dam releases on velocity and longitudinal dispersion of flow was evaluated by injecting a fluorescent dye into the Colorado River below Glen Canyon Dam and sampling for dye concentration at selected sites downstream. Measurements of a 26-kilometer reach of Glen Canyon, just below Glen Canyon Dam, were made at nearly steady dam releases of 139, 425, and 651 cubic meters per second. Measurements of a 380-kilometer reach of Grand Canyon were made at steady releases of 425 cubic meters per second and at unsteady releases with a daily mean of about 425 cubic meters per second. In Glen Canyon, average flow velocity through the study reach increased directly with discharge, but dispersion was greatest at the lowest of the three flows measured. In Grand Canyon, average flow velocity varied slightly from subreach to subreach at both steady and unsteady flow but was not significantly different at steady and unsteady flow over the entire study reach. Also, longitudinal dispersion was not significantly different during steady and unsteady flow. Long tails on the time-concentration curves at a site, characteristic of most rivers but not predicted by the one-dimensional theory, were not found in this study. Absence of tails on the curves shows that, at the measured flows, the eddies that are characteristic of the Grand Canyon reach do not trap water for a significant length of time. Data from the measurements were used to calibrate a one-dimensional flow model and a solute-transport model. The combined set of calibrated flow and solute-transport models was then used to predict velocity and dispersion at potential dam-release patterns. 相似文献
965.
Lawrence J. MacDonnell David H. Getches William C. Hugenberg 《Journal of the American Water Resources Association》1995,31(5):825-836
ABSTRACT: The waters of the Colorado River are divided among seven states according to a complex ‘Law of the River’ drawn from interstate compacts, international treaties, statutes, and regulations. The Law of the River creates certain priorities among the states and the Republic of Mexico, and in the event of a severe sustained drought, the Law of the River dictates the distribution of water and operation of the elaborate reservoir system. Earlier work indicated that there is remarkable resilience in the system for established uses of water in the Lower Basin of the Colorado River. This work shows, based on an application of the Law of the River using computer modeling of operations of facilities on the Colorado River, that there may be serious environmental consequences and related legal restraints on how the water is used in times of shortage and that the existing legal and institutional framework governing the Colorado River does not adequately address all the issues that would be raised in a severe sustained drought. Several possible legal options for dealing with drought in the context of the Law of the River are identified. 相似文献
966.
Richard S. Krannich Sean P. Keenan Michael S. Walker Donald L. Hardesty 《Journal of the American Water Resources Association》1995,31(5):851-865
ABSTRACT: Survey data collected in the San Joaquin Valley of southern California and the Grand Valley of western Colorado reveal that residents of both areas believe that a severe sustained drought is likely to occur within the next 20–25 years and that their communities would be seriously impacted by such an event. Although a severe sustained drought affecting the Colorado River Basin would cause major economic and social disruptions in these and other communities, residents express little support for water management alternatives that would require significant shifts in economic development activities or in water use and allocation patterns. In particular, residents of these areas express little support for strategies such as construction and growth moratoriums, mandatory water conservation programs, water transfers from low-to high-population areas, water marketing, or reallocations of water from agricultural to municipal/industrial uses. This rejection of water management strategies that would require a departure from “business as usual” with respect to water use and allocations severely restricts the capacity of these and similar communities to respond effectively should a severe sustained drought occur. 相似文献
967.
Taiye B. Sangoyomi Benjamin L. Harding 《Journal of the American Water Resources Association》1995,31(5):925-938
ABSTRACT: We evaluated the effects of institutional responses developed for coping with a severe sustained drought (SSD) in the Colorado River Basin on selected system variables using a SSD inflow hydrology derived from the drought which occurred in the Colorado River basin from 1579–1616. Institutional responses considered are reverse equalization, salinity reduction, minimum flow requirements, and temporary suspension of the delivery obligation of the Colorado River Compact. Selected system variables (reservoir contents, streamflows, consumptive uses, salinity, and power generation) from scenarios incorporating the drought-coping responses were compared to those from Baseline conditions using the current operating criteria. The coping responses successfully mitigated some impacts of the SSD on consumptive uses in the Upper Basin with only slight impacts on consumptive uses in the Lower Basin, and successfully maintained specified minimum streamflows throughout the drought with no apparent effect on consumptive uses. The impacts of the coping responses on other system variables were not as clear cut. We also assessed the effects of the drought-coping responses to normal and wet hydrologic conditions to determine if they were overly conservative. The results show that the rules would have inconsequential effects on the system during normal and wet years. 相似文献
968.
This article investigates the impact of ISO 14001 certification on the compliance with environmental regulations by Korean companies. The impact of ISO 14001 certification on the industry was studied through a questionnaire survey and the compliance of environmental regulations were investigated using government-released data. The motivation for an environment management system was a result of the current international situation and the need to maintain fair competition. ISO 14001 certification has been recognized as an essential strategy for industrial competition and to improve company/product recognition. The certified and non-certified companies' environmental regulation violation (ERV) rates were 3.5% and 11.6%, respectively, in 1997. In 1998, the ERV rate had an eight-time difference with 1.0% and 8.5% for certified and non-certified companies, respectively. Annual regulation violation rates were reduced from 3.5% in 1997 to 1.0% in 1998 with certified companies and from 11.6% in 1997 to 8.5% in 1998 with their non-certified counterparts, respectively. ISO 14001 certified companies showed more improvement than non-certified companies in regards to environmental performance. 相似文献
969.
Environmental impact assessment of a proposed info-tech complex in East Calcutta wetlands 总被引:1,自引:0,他引:1
An info-tech complex is proposed for 286 acres (116 ha) of land within the East Calcutta wetlands. The proposed site is 15 km east of Kolkata city and only 8 km south of Dum Dum airport. The site is vacant, with pockets of agricultural land and a few degrading water-logged areas. In order to assess the likely impact of the proposed development on the environment, a rapid environmental impact assessment of an area of 10 km radius from the centre of the project site was carried out. The present status of the environment with respect to ambient air, surface water, groundwater, soil, landuse, noise, and socio-economics of the core and buffer zone has been documented and correlated with 24 project activities during construction, development and operational phases. The frequency of adverse impacts is greater than that of beneficial impacts. Out of the total adverse impacts 20 are short term, reversible and have a low magnitude. The total impact score for the proposed project is (–)468.75 and as per the Assessment Value Index Scale the environmental impact of the proposed project activities is no appreciable impact. But there are certain sectors where the environment will be adversely impacted. Therefore, appropriate measures have been suggested to ameliorate the adverse impacts. It is envisaged that if these measures are implemented then there will be an improvement in the quality of the environment, as well as life, by 687.5 units. 相似文献
970.
An Experiment in Participative Environmental Decision Making 总被引:2,自引:0,他引:2
Summary The paper presents a method of participatory decision-making involving the authorities at local level, experts and the public.
It studies how to solve the problems caused by the heterogeneity of the parties taking part in the decision-making process.
The method builds on mutual learning and consideration among the participants following a systematic approach led by a moderator.
The method was tested at a workshop simulating a real-life situation. The test case studied at the workshop was the problem
of identifying the best site for a low and intermediate level radioactive waste repository among three alternatives. The learning
phase was the Krško Nuclear Power Plant cooling problem. The results show that the participants were able to reach agreement
on the prioritisation of the alternatives and to end up with suprisingly complex and fully reasonable decision models. We
believe that this was achieved particularly due to the well defined procedure that guided the decision-making process, and
the ability of all participants to see the influence of their views on the decision model. 相似文献