全文获取类型
收费全文 | 217篇 |
免费 | 22篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 4篇 |
环保管理 | 15篇 |
综合类 | 36篇 |
基础理论 | 163篇 |
污染及防治 | 10篇 |
评价与监测 | 5篇 |
社会与环境 | 14篇 |
出版年
2023年 | 11篇 |
2022年 | 11篇 |
2021年 | 10篇 |
2020年 | 22篇 |
2019年 | 13篇 |
2018年 | 9篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 15篇 |
2012年 | 9篇 |
2011年 | 13篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 11篇 |
2007年 | 14篇 |
2006年 | 11篇 |
2005年 | 14篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1987年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有247条查询结果,搜索用时 0 毫秒
111.
Forest Health Monitoring in the United States: First Four Years 总被引:24,自引:0,他引:24
To address the need for more effective methods for evaluating and assessing forest ecosystem health, the USDA-Forest Service and the US Environmental Protection Agency through its Environmental Monitoring and Assessment Program developed the Forest Health Monitoring program. The program was initiated in 1990 and by 1994 was present in the major areas of the United States. This paper presents an overview of the program, the indicators and methods developed for the program, and some of the results after four years of monitoring and research. 相似文献
112.
2008年7月—2010年9月,对珠海淇澳岛红树林不同生境和不同植被群落的蟹类进行了调查,共采集到蟹类8科24种,其中相手蟹科Sesarmidae种类最多,为9种;弓蟹科Varunidae次之,为5种,沙蟹科Ocypodidae 4种。Jaccard区系相似性指数表明,林内泥滩与林外硬质泥滩蟹类区系为中等相似(J=0.523),林外硬质泥滩与高潮区光滩蟹类区系(J=0.071)及林内泥滩与高潮区光滩蟹类区系(J=0)都极不相似。林内泥滩蟹类中,谭氏泥蟹(Ilyoplax deschampsi)在数量上占绝对优势。无齿螳臂相手蟹(Chiromantes dehaani)、中华中相手蟹(Sesarmops sinensis)和弧边招潮蟹(Uca arcuata)等在红树林外道路两侧和堤坝较硬质泥滩数量较多,而林外高潮区光滩的蟹类都是耐干旱和奔跑能力较强的种类。天然秋茄(Kandelia candel)群落蟹类种类数和平均密度较人工引种的无瓣海桑(Sonneratia apetala)群落的少,但平均生物量较无瓣海桑群落高。秋茄群落蟹类密度和生物量与土壤全氮、全磷、有机质等理化因子都呈不显著相关;无瓣海桑群落土壤速效磷与蟹类生物量呈极显著正相关,与蟹类密度呈显著正相关;全磷与蟹类密度呈显著负相关。红树林土壤类型和新生蟹类补充进种群是影响珠海淇澳岛红树林蟹类密度和生物量变化的主要原因。 相似文献
113.
SAMUEL A. CUSHMAN KEVIN S. McKELVEY BARRY R. NOON KEVIN McGARIGAL 《Conservation biology》2010,24(3):830-840
Abstract: Indicator species concepts have a long history in conservation biology. Arguments in favor of these approaches generally stress expediency and assume efficacy. We tested the premise that the abundance patterns of one species can be used to infer those of other species. Our data consisted of 72,495 bird observations on 55 species across 1046 plots distributed across 30 sub basins. We analyzed abundance patterns at two spatial scales (plot and sub basin) and for empirical and a priori grouping. There were few significant indicator relationships at either scale or under either grouping rule, and those few we found did not explain a substantial portion of the abundance of other species. Coupled with the lack of proven efficacy for species surrogacy in the literature, our results indicate the utility of indicators and similar types of surrogate approaches must be demonstrated rather than assumed. 相似文献
114.
选取中国鄱阳湖南矶山湿地为研究范围,通过分析候鸟在越冬期的栖息特征,构建适宜于提取候鸟栖息地的湿地分类系统。以Landsat8卫星OLI遥感影像为数据源,采用面向对象分类方法,通过多尺度分割、特征提取和决策树建立等关键步骤,实现湿地信息的快速提取;通过与传统像元法的分类结果对比,系统分析了面向对象方法在基于中低分辨率遥感影像的湿地信息提取中的有效性。研究表明:在面向对象湿地信息提取中,构建不同等级的分割尺度,在多个尺度上提取同一地物,可以更好识别复杂的湿地景观类型;相比仅依据像元光谱特征进行分类的传统像元方法,面向对象方法综合利用光谱、空间、形状和纹理等多种特征,因此可以获得更高的精度(总体分类精度达到87.64%,Kappa系数为 0.855 2);基于中低分辨率遥感影像,采用面向对象分类方法,能够获得较高精度的湿地景观分布,是一种成本较低且行之有效的技术手段。 相似文献
115.
D. V. Quayle 《Chemistry and Ecology》1992,6(1):69-78
Plastics debris is known to be present in all of the world's oceans, and on most amenity beaches, although comparatively little data are available to provide reliable information on the extent of damage from this pollution, and on its spatial and temporal variations.
Marine pollution by plastics has been shown to be damaging to marine mammals, birds and reptiles. This is due to entanglement in packaging bands, synthetic ropes and lines, or drift nets; or by the ingestion of small items of plastics debris. More research is needed to quantify the extent of the problems.
Wider use of degradable plastics will not solve the problems of plastics pollution. Their lifetimes are relatively long and unpredictable, and they are not generally acceptable for recycling.
Marine plastics pollution may be alleviated by the judicious application of both economic incentives and legislation, designed to decrease their use, to increase the rate of recycling, and to restrict uncontrolled discards. 相似文献
Marine pollution by plastics has been shown to be damaging to marine mammals, birds and reptiles. This is due to entanglement in packaging bands, synthetic ropes and lines, or drift nets; or by the ingestion of small items of plastics debris. More research is needed to quantify the extent of the problems.
Wider use of degradable plastics will not solve the problems of plastics pollution. Their lifetimes are relatively long and unpredictable, and they are not generally acceptable for recycling.
Marine plastics pollution may be alleviated by the judicious application of both economic incentives and legislation, designed to decrease their use, to increase the rate of recycling, and to restrict uncontrolled discards. 相似文献
116.
米埔湿地冬季鸟类对气象及生态质量响应研究 总被引:1,自引:0,他引:1
为探讨气象及生态气象质量与湿地生态系统内鸟类变化的关系,文章以香港米埔湿地为例,利用米铺湿地1979—2009年留鸟人工观测数据、香港天文台公布气象数据和以2000—2009年4期等时间间距研究区的景观变化数据,分析湿地内留鸟数量对研究区气象及生态气象质量变化的响应。结果表明:(1)湿地留鸟数量与温度和最低能见度时数相关性显著,与降水量和月均日照时数变化相关性较小;(2)5种生态气象评价指数(EMI)与同期鸟类数量的相关性分析表明,留鸟与综合生态评价指数(ECAI)呈正相关。其中与水体指数(WDI)正相关系数最大,与土地利用退化指数(LDI)负相关系数最大,相关系数分别为0.88和-0.85;而与湿润指数(HI)和植被指数(VDI)相关性较小。研究表明,保护生态环境,调节气候变化幅度,对保护留鸟的生存空间,延续生物的生态平衡具有重要意义。 相似文献
117.
采用分解袋法,研究了川西亚高山云杉纯林与混交林叶凋落物的质量损失过程及土壤动物与微生物的作用。结果如下:(1)云杉叶凋落物分解过程中,土壤动物数量总体呈下降趋势,即土壤动物主要在分解前期发挥作用,其中,大型土壤动物早期以植食性的蛴螬为主,中期以捕食性的石蜈蚣为主,后期以腐食性的马陆为主;中小型土壤动物始终以螨类、跳虫和线虫为优势类群;相关分析表明线虫数量与云杉叶凋落物分解速率相关性最大,大型土壤动物次之。(2)云杉叶凋落物分解过程中,微生物数量总体呈上升趋势,即土壤微生物主要在分解后期发挥作用,进一步相关分析表明真菌数量与云杉叶凋落物分解速率相关性大于细菌和放线菌。(3)云杉纯林叶凋落物分解速率低于混交林,其中分解3、15、21、24个月时,纯林小孔径分解袋失重率分别为混交林的65.51%、95.73%、98.91%、94.8%,大孔径分解袋失重率分别为混交林的89.83%、92.95%、98.13%、97.13%,即,两类林分小孔径分解袋及凋落物分解前期失重率差异更为明显,表明凋落物分解速率既受底物质量的影响,也和参与分解的土壤生物有关,其中与线虫、大型土壤动物及真菌的数量相关性最大。 相似文献
118.
湿地鸟类多样性及其环境影响因子的研究进展 总被引:7,自引:0,他引:7
湿地鸟类在能量转换和维护生态系统的稳定性方面起着举足轻重的作用,同时也是监测、评价湿地生态环境极其敏感的指标.本文从物种多样性、遗传多样性和生态系统多样性三个方面分析了湿地鸟类多样性.总结了环境因子对湿地鸟类多样性的影响,最后对湿地鸟类多样性的研究提出展望,为更好地保护湿地鸟类资源及生态环境提供科学依据. 相似文献
119.
Neil R. Jordan Bradley P. Smith Robert G. Appleby Lily M. van Eeden Hugh S. Webster 《Conservation biology》2020,34(4):803-810
Millennia of human conflict with wildlife have built a culture of intolerance toward wildlife among some stakeholders. We explored 2 key obstacles to improved human–wildlife coexistence: coexistence inequality (how the costs and benefits of coexisting with wildlife are unequally shared) and intolerance. The costs of coexisting with wildlife are often disproportionately borne by the so-called global south and rural communities, and the benefits often flow to the global north and urban dwellers. Attitudes and behaviors toward wildlife (tolerance versus intolerance) vary with social and cultural norms. We suggest more empathetic advocacy is needed that, for example, promotes conservation while appropriately considering those who bear the costs of conflict with wildlife. To achieve more equitable cost-sharing, we suggest limiting the costs incurred by those most affected or by sharing those costs more widely. For example, we advocate for the development of improved wildlife compensation schemes, increasing the scale of rewilding efforts, and preventing wildlife-derived revenue leaching out of the local communities bearing the costs of coexistence. 相似文献
120.
Laura R. Perry Tom P. Moorhouse Andrew J. Loveridge David W. Macdonald 《Conservation biology》2020,34(4):879-890
Conflict between people and carnivores can lead to the widespread killing of predators in retaliation for livestock loss and is a major threat to predator populations. In Kenya, a large, rural, pastoralist population comes into regular conflict with predators, which persist across southern Kenya. We explored the social and psychological backdrop to livestock management practices in this area in a process designed to be easy to use and suitable for use across large areas for the study of conflict and transboundary implementation of wildlife conflict reduction measures, focusing on community involvement and needs. We carried out fully structured interviews of livestock managers with a survey tool that examined how social and psychological factors may influence livestock management behavior. We compared survey responses on 3 sites across the study area, resulting in 723 usable responses. Efficacy of individuals’ livestock management varied between and within communities. This variation was partially explained by normative and control beliefs regarding livestock management. Individual livestock managers’ self-reported management issues were often an accurate reflection of their practical management difficulties. Psychological norms, control beliefs, and attitudes differed among sites, and these differences partially explained patterns associated with conflict (i.e., variation in livestock management behavior). Thus, we conclude that a one-size-fits-all approach to improving livestock management and reducing human–predator conflict is not suitable. 相似文献