全文获取类型
收费全文 | 1637篇 |
免费 | 44篇 |
国内免费 | 35篇 |
专业分类
安全科学 | 113篇 |
废物处理 | 11篇 |
环保管理 | 348篇 |
综合类 | 730篇 |
基础理论 | 184篇 |
环境理论 | 2篇 |
污染及防治 | 79篇 |
评价与监测 | 159篇 |
社会与环境 | 69篇 |
灾害及防治 | 21篇 |
出版年
2024年 | 3篇 |
2023年 | 14篇 |
2022年 | 14篇 |
2021年 | 29篇 |
2020年 | 58篇 |
2019年 | 19篇 |
2018年 | 16篇 |
2017年 | 45篇 |
2016年 | 50篇 |
2015年 | 43篇 |
2014年 | 60篇 |
2013年 | 75篇 |
2012年 | 65篇 |
2011年 | 112篇 |
2010年 | 80篇 |
2009年 | 130篇 |
2008年 | 89篇 |
2007年 | 106篇 |
2006年 | 94篇 |
2005年 | 82篇 |
2004年 | 56篇 |
2003年 | 78篇 |
2002年 | 72篇 |
2001年 | 43篇 |
2000年 | 58篇 |
1999年 | 42篇 |
1998年 | 29篇 |
1997年 | 18篇 |
1996年 | 19篇 |
1995年 | 23篇 |
1994年 | 9篇 |
1993年 | 23篇 |
1992年 | 19篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1716条查询结果,搜索用时 820 毫秒
821.
通过解读"十一五"末期国家城考新指标,结合城考工作新形势,剖析当今新疆城市环境综合整治定量考核工作中存在的具体问题,提出新疆城市城考工作具有建议性的意见,为"十二五"期间新疆城市有的放失地推动城考工作提供依据. 相似文献
822.
Urbanization is a dominant component of social and economic development around the world, but this process creates tremendous pressure on the ecological environment. How to achieve coordination between urbanization and conservation of this environment has become a key issue, especially in developing countries. It is necessary to identify the driving factors that affect this coordination. To identify these factors, we chose 290 Chinese prefecture-level cities to analyze the driving factors behind urbanization using spatial regression analysis, and explored the spatial differences among regions in these factors. Our results show that industrial upgrading and technological progress were the main factors that promoted coordinated development, with industrialization having positive effects under government management, but with differences among regions in how the driving forces affected coordinated development. Using technological progress to promote industrial upgrading, creating new employment to absorb surplus rural labor, and providing workers with skills training so they can take advantage of new jobs can promote win–win solutions that coordinate urbanization with conservation of the ecological environment. 相似文献
823.
824.
高校要加强大学生礼仪教育 总被引:1,自引:0,他引:1
本文列举了大学生在学校多种场合和情景中礼仪素养缺失的种种表现,并多方面分析问题产生的原因,最后简要提出了高校要加强大学生礼仪教育的对策。 相似文献
825.
D. J. Schaeffer T. R. Seastedt D. J. Gibson D. C. Hartnett B. A. D. Hetrick S. W. James D. W. Kaufman A. P. Schwab E. E. Herricks E. W. Novak 《Environmental management》1990,14(1):81-93
Ecosystem responses to physical or chemical stress may vary from changes in single organisms to alteration of the structure
and function of the ecosystem. These responses to stress cannol be predicted exactly. Ecosystems repeatedly exposed to physical
and/or chemical stress can be used to study the separate and combined environmental effects of stress. Such studies also allow
the development of procedures to select test systems for the analysis of stress in ecosystems. A preliminary field survey
of six military training sites at Fort Riley, Kansas, USA, was conducted to identify and verify ecological test systems for
evaluating ecosystem responses to physical and/or chemical stress. Comparisons of these data with data collected concurrently
from Konza Prairie Research Natural Area reference sites showed that soil microarthropods, some species of macroarthropods,
small mammals, and native earthworm species were negatively affected by stress. In contrast, plant species diversity, plant
foliage biomass, soil mycorrhizae, and many soil characteristics were within the boundaries of nominal variations observed
on “pristine” Konza Prairie. Introduced European earthworms appeared to be positively affected by training activities. This
study provided a test of systematic procedures to support impact analysis, ecological toxicology, and ecosystem risk assessments.
This is paper IX in D. J. Schaeffer's “Environmental Audit” series. 相似文献
826.
How and when migrants integrate directional information from different sources may depend not only on the bird’s internal
state, including fat stores, but also on the ecological context during passage. We designed experiments to (1) examine the
influence of stored fat on the decision to migrate and on the choice of migratory direction and (2) investigate how the integration
of orientation cue information is tied to energetic status in relation to migration across an ecological barrier. Migratory
orientation of red-eyed vireos (Vireo olivaceus) at twilight was recorded using two different techniques, orientation cage experiments and free-flight release tests, during
both fall and spring migration. During fall migration, the amount of stored fat proved decisive for directional selections
of the vireos. Fat birds chose directions in accordance with migration across the Gulf of Mexico. Lean birds oriented either
parallel to the coast line (cage tests) or moved inland (free-flight releases). Whereas only fat birds showed significant
responses to experimental deflections of the geomagnetic field, lean birds displayed a tendency to shift their activity in
the expected direction, making it difficult to evaluate the prediction that use of the magnetic compass is context dependent.
Fat loads also had a significant effect on the decision to migrate, i.e., fat individuals were more likely to embark on migration
than were lean birds (true for both cage and release experiments). During spring migration, a majority of experimental subjects
were classified as lean, following their arrival after crossing the Gulf of Mexico, and oriented in seasonally appropriate
directions. The vireos also showed significant responses to experimental deflections of the geomagnetic field regardless of
their energetic status. Free-flight release experiments during spring migration revealed a significant difference in mean
directions between clear sky and overcast tests. The difference may indicate a compensatory response to wind drift or possibly
a need for celestial cues to calibrate the magnetic compass. Finally, this is the first demonstration of magnetic compass
orientation in a North American vireo.
Received: 15 December 1995/Accepted after revision: 24 March 1996 相似文献
827.
本文从社会需要的两极保障是社会稳定与发展的前提出发,论述了社会需要、自然环境与灾害的关系;并从发展生产与引导人的需要两方面阐述了维护生态平衡是减灾工作的重点途径之一。 相似文献
828.
Profiles of and variations in aluminum species in PAC-MC used for the removal of blooming microalgae
Polyaluminum chloride modified clay (PAC-MC) is a safe and efficient red tide control agent that has been studied and applied worldwide. Although it is well known that the distribution of hydrolytic aluminum species in PAC affects its flocculation, little is known about the influence of particulars aluminum species on the microalgae removal efficiency of PAC-MC; this lack of knowledge creates a bottleneck in the development of more efficient MCs based on aluminum salts. The ferron method was used in this study to quantitatively analyze the distributions of and variations in different hydrolytic aluminum species during the process of microalgae removal by PAC-MC. The results showed that Ala, which made up 5%–20% of the total aluminum, and Alp, which made up 15%–55% of the total aluminum, significantly affected microalgae removal, with Pearson's correlation coefficients of 0.83 and 0.89, respectively. Most of the aluminum in the PAC-MC sank rapidly into the sediments, but the rate and velocity of settlement were affected by the dose of modified clay. The optimal dose of PAC-MC for precipitating microalgae was determined based on its aluminum profile. These results provide guidance for the precise application of PAC-MC in the control of harmful algal blooms. 相似文献
829.
快速工业化区域建设用地问题与制度优化研究——以佛山市南海区为例 总被引:3,自引:0,他引:3
快速工业化区域是工业化快速发展、工业化水平迅速提升、经济社会结构急剧变化的新兴地域类型。普遍存在着建设用地总量急剧扩张、空间无序分散、城乡缺乏统筹等问题。本文从佛山市南海区典型案例入手,运用新制度经济学原理。归纳和解析了快速工业化区域城乡建设用地的主要问题,认为双二元管理体制、农村土地产权不完善、城乡土地市场发育不平衡和部门规划不协调等是建设用地发展的主要体制性障碍因素,并从管理、产权、市场、规划等方面系统提出相应的制度优化对策。 相似文献
830.
Exposing ecological and economic costs of the research‐implementation gap and compromises in decision making
下载免费PDF全文
![点击此处可从《Conservation biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Santtu Kareksela Atte Moilanen Olli Ristaniemi Reima Välivaara Janne S. Kotiaho 《Conservation biology》2018,32(1):9-17
The frequently discussed gap between conservation science and practice is manifest in the gap between spatial conservation prioritization plans and their implementation. We analyzed the research‐implementation gap of one zoning case by comparing results of a spatial prioritization analysis aimed at avoiding ecological impact of peat mining in a regional zoning process with the final zoning plan. We examined the relatively complex planning process to determine the gaps among research, zoning, and decision making. We quantified the ecological costs of the differing trade‐offs between ecological and socioeconomic factors included in the different zoning suggestions by comparing the landscape‐level loss of ecological features (species occurrences, habitat area, etc.) between the different solutions for spatial allocation of peat mining. We also discussed with the scientists and planners the reasons for differing zoning suggestions. The implemented plan differed from the scientists suggestion in that its focus was individual ecological features rather than all the ecological features for which there were data; planners and decision makers considered effects of peat mining on areas not included in the prioritization analysis; zoning was not truly seen as a resource‐allocation process and not emphasized in general minimizing ecological losses while satisfying economic needs (peat‐mining potential); and decision makers based their prioritization of sites on site‐level information showing high ecological value and on single legislative factors instead of finding a cost‐effective landscape‐level solution. We believe that if the zoning and decision‐making processes are very complex, then the usefulness of science‐based prioritization tools is likely to be reduced. Nevertheless, we found that high‐end tools were useful in clearly exposing trade‐offs between conservation and resource utilization. 相似文献