全文获取类型
收费全文 | 794篇 |
免费 | 33篇 |
国内免费 | 36篇 |
专业分类
安全科学 | 32篇 |
废物处理 | 2篇 |
环保管理 | 310篇 |
综合类 | 196篇 |
基础理论 | 142篇 |
环境理论 | 1篇 |
污染及防治 | 35篇 |
评价与监测 | 52篇 |
社会与环境 | 59篇 |
灾害及防治 | 34篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 11篇 |
2021年 | 15篇 |
2020年 | 20篇 |
2019年 | 14篇 |
2018年 | 21篇 |
2017年 | 23篇 |
2016年 | 30篇 |
2015年 | 19篇 |
2014年 | 27篇 |
2013年 | 49篇 |
2012年 | 40篇 |
2011年 | 58篇 |
2010年 | 43篇 |
2009年 | 53篇 |
2008年 | 52篇 |
2007年 | 57篇 |
2006年 | 47篇 |
2005年 | 27篇 |
2004年 | 24篇 |
2003年 | 16篇 |
2002年 | 18篇 |
2001年 | 19篇 |
2000年 | 22篇 |
1999年 | 17篇 |
1998年 | 12篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 1篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1973年 | 1篇 |
排序方式: 共有863条查询结果,搜索用时 15 毫秒
81.
A “finding of no significant impact” (FONSI) resulting from an environmental assessment (EA) was reported by the US Army in
June 1986 for the construction and utilization of a multipurpose range complex (MPRC) at the Pohakuloa Training Area, Hawaii.
There was little public response, and the US Fish and Wildlife Service and state agencies were consulted and had few comments
concerning the results of the botanical surveys used in the assessment. Construction of the $24 million project was begun
in 1988. Near the end of construction in 1989 a lawsuit was filed to halt construction because an environmental impact statement
(EIS) had not been done for the project, and the plaintiff thought that significant damage had occurred to several unusual
ecosystems. Judgment was against the plaintiff and construction continued. An appeal was filed with the 9th Circuit Court.
As MPRC construction was nearly complete, and on advice of Department of Justice lawyers, the Department of Army agreed to
settle out of court. The settlement in part called for: (1) the plaintiff to drop the appeal and allow construction to be
completed as scheduled, and (2) the Department of Army to prepare an EIS for the operation of the MPRC. A subsequent botanical
survey for the EIS discovered one endangered plant species, four category 1 candidate plant species (taxa with sufficient
data to support listing as endangered or threatened), three category 2 candidate plant species (taxa with some evidence of
vulnerability but insufficient data to support listing at this time), one category 3a species (presumably extinct taxa), and
possibly three undescribed species growing within the MPRC boundary. The MPRC case study is an excellent example of why the
National Environmental Policy Act (NEPA) must be modified to require in-depth and thorough environmental surveys. 相似文献
82.
长江流域的鱼类资源及其保护对策 总被引:40,自引:7,他引:33
刘健康|曹文宣 《长江流域资源与环境》1992,1(1):3-23
长江水系的鱼类约有300种,其中鲤科鱼类占半数以上,主要的经济鱼类多数属于鲤科。对不同江段的鱼类资源作了简介,并提出了相应的保护措施。上游江段以维护生物多样性,保护特有种为主,需要建立鱼类自然保护区;中游应保证主要经济鱼类的自然繁殖条件,加强珍稀鱼类的人工繁殖放流工作,同时对湖泊幼鱼资源进行保护;下游应注意保持江水质量,严格遵守工业废水排放标准;河口江段应规定幼鲟保护期,建议每年6月15日至7月31日停止一切损害幼鲟资源的渔捞作业。 相似文献
83.
Aquatic macroinvertebrate diversity in the Nanda Devi Biosphere Reserve (NDBR) was monitored for a period of twelve months (September 2000 to August 2001). All the important hydrological attributes were measured monthly for one year. Macroinvertebrates were sampled from three sites (S1$, S2$, & S3$) of the headwater stream Dhauliganga of NDBR. The present study revealed that the velocity of the water current, hydromedian depth, turbidity and dissolved oxygen in addition to nature and size of the bottom substrates have their significant impact on benthic invertebrate diversity. The ecological relevance of the measured hydrological attributes was investigated by comparing their degree of correlation with invertebrate density and diversity. Macroinvertebrate diversity was found to be highest (3.096 ± 0.03) in winter months (November–January) and lowest (2.816 ± 0.02) in monsoon months (July–August). The high diversity of macroinvertebrates may be due to low turbidity, high water transparency, optimum water temperature, high dissolved oxygen, low water velocity and suitable composition of the bottom substrates. 相似文献
84.
Travis C Obenshain KR Gunter JT Regens JL Whipple C 《Environmental science and pollution research international》2004,11(5):302-306
GOAL, SCOPE AND BACKGROUND: This paper uses two case studies of U.S. Department of Energy nuclear weapons complex installations to illustrate the integration of expedited site characterization (ESC) and multimedia modeling in the remedial action decision making process. CONCEPTUAL SITE MODELS, MULTIMEDIA MODELS, AND EXPEDITED SITE CHARACTERIZATION: Conceptual site models outline assumptions about contaminates and the spatial/temporal distribution of potential receptors. Multimedia models simulate contaminant transport and fate through multiple environmental media, estimate potential human exposure via specific exposure pathways, and estimate the risk of cancer and non-cancer health outcomes. ESC relies on using monitoring data to quantify the key components of an initial conceptual site model that is modified iteratively using the multimedia model. CASE STUDIES: Two case studies are presented that used the ESC approach: Los Alamos National Laboratory (LANL) and Pantex. LANL released radionuclides, metals, and organic compounds, into canyons surrounding the facility. The Pantex Plant has past waste management operations which included burning chemical wastes in unlined pits, burying wastes in unlined landfills, and discharging plant wastewaters into on-site surface waters. CONCLUSIONS: The case studies indicate that using multimedia models with the ESC approach can inform assessors about what, where, and how much site characterization data needs to be collected to reduce the uncertainty associated with risk assessment. Lowering the degree of uncertainty reduces the time and cost associated with assessing potential risk and increases the confidence that decision makers have in the assessments performed. 相似文献
85.
Benefits-based management seeks to provide recreation benefits for recreation participants by managing the physical environments
in which recreation occurs. This study investigates the relationship between benefits desired by visitors and the physical,
social, and managerial characteristics of settings that facilitate realization of recreation benefits. Data such as perceived
benefits from recreation experiences, setting attributes that significantly influenced perceived benefits, and sociodemographic
variables were collected from 376 visitors to Sorak-san National Park in the eastern part of the Korean peninsula. Cluster
analysis was used to group visitors' desired benefits into 12 domains: relationship with nature/scenery, escaping pressure,
learning about nature, family togetherness, introspection, exploration, autonomy/achievement, being with friends, leading
others, skills/learning, risk taking, and meeting/observing new people. Multiple regression was used to link benefit domains
with the characteristics of settings. The social attribute of recreation settings was linked to eight of the ten benefit domains.
There were two statistically strong multiple regression correlations: (1) between domain of “relationship with nature /scenery”
and the attributes “forest/water,”“attractive nature,” and “facility/maintenance” and (2) between the domain of “escaping
pressure” and the attributes “attractive nature” and “social.” The results of this study are useful to managers in their efforts
to provide recreation opportunities for visitors to achieve beneficial outcomes. 相似文献
86.
Bogaert J Salvador-Van Eysenrode D Impens I Van Hecke P 《Environmental management》2001,27(4):493-500
A method is proposed to quantify disturbance impact on isolated habitats. For every landscape patch, the breakpoint distance,
defined as the penetration distance for which equality of interior and edge habitat is observed, can be calculated. Disturbance
with equal impact at all patch sides is assumed. Effects of patch compactness, size, convolution, and perforation are discussed.
The potential use of the measure for nature reserve design is discussed. The breakpoint distance follows the reserve design
guidelines for individual patches, based on island biogeography and is consistent with the form and function principle. A
large breakpoint distance is preferred for natural habitats. Small size, small compactness, intense convolution, and the occurrence
of many gaps depress the breakpoint distance. 相似文献
87.
Fire occurrences and their sources were monitored in Emas National Park, Brazil (17°49′–18°28′S; 52°39′–53°10′W) from June
1995 to May 1999. The extent of burned area and weather conditions were registered. Forty-five fires were recorded and mapped
on a GIS during this study. Four fires occurred in the dry winter season (June–August; 7,942 ha burned), all caused by humans;
10 fires occurred in the seasonally transitional months (May and September) (33,386 ha burned); 31 fires occurred in the wet
season, of which 30 were caused by lightning inside the park (29,326 ha burned), and one started outside the park (866 ha
burned). Wet season lightning fires started in the open vegetation (wet field or grassy savanna) at a flat plateau, an area
that showed significantly higher fire incidence. On average, winter fires burned larger areas and spread more quickly, compared
to lightning fires, and fire suppression was necessary to extinguish them. Most lightning fires were patchy and extinguished
primarily by rain. Lightning fires in the wet season, previously considered unimportant episodes, were shown to be very frequent
and probably represent the natural fire pattern in the region. Lightning fires should be regarded as ecologically beneficial,
as they create natural barriers to the spread of winter fires. The present fire management in the park is based on the burning
of preventive firebreaks in the dry season and exclusion of any other fire. This policy does not take advantage of the beneficial
effects of the natural fire regime and may in fact reduce biodiversity. The results presented here stress the need for reevaluating
present policies and management procedures concerning fire in cerrado conservation areas. 相似文献
88.
89.
Başak K. Taşeli 《The Environmentalist》2007,27(3):315-327
Environmental pollution and degradation of ecosystems considerably affect the natural resources. The Turkish Government is
aware of the importance of the preservation of natural ecology and thereby the environmental conservation of many species
in their natural habitat. This paper provides critical assessments of the problems and possible solutions in the identification,
implementation and management of the Specially Protected Areas (SPAs) system by giving basic information about stakeholders
and their responsibilities that currently offer nature conservation in Turkey. The goals of the article are to analyze how
the SPAs interface with the local people, especially the villagers who have dwelt there before SPA designation and how people-SPA
conflicts resolved; to show how effective the SPA conservation objectives have been; to outline the significance of informing
and empowering people in nature conservation for the protected area management and to show the importance of planning at all
levels during protection of the natural, archeological and cultural values of the SPAs. 相似文献
90.
Ben A. Minteer Elizabeth A. Corley 《Journal of Agricultural and Environmental Ethics》2007,20(4):307-333
Few disputes in the annals of US environmentalism enjoy the pedigree of the conservation-preservation debate. Yet, although
many scholars have written extensively on the meaning and history of conservation and preservation in American environmental
thought and practice, the resonance of these concepts outside the academic literature has not been sufficiently examined.
Given the significance of the ideals of conservation and preservation in the justification of environmental policy and management,
however, we believe that a more detailed analysis of the real-world use and understanding of these ideas is needed. In this
paper, we describe the results of a qualitative, semantic study of the concepts of conservation and preservation undertaken
in the context of the Chattahoochee National Forest (CNF), located in northern Georgia (USA). Thirty in-depth interviews were
conducted with scientists and north Georgia residents either interested or involved in the future management of the forest.
Respondents were asked to define conservation and preservation in their own words and to indicate which approach they felt
was more appropriate for the management of the CNF. Qualitative content analysis was used to elicit a set of recurring themes
for each foundational concept. Taken together, these themes help to flesh out the meaning of conservation and preservation
for citizens and scientists today, and illustrate the evolving nature of two of the more significant and venerable ideas animating
US environmental policy and management. 相似文献