全文获取类型
收费全文 | 17238篇 |
免费 | 172篇 |
国内免费 | 120篇 |
专业分类
安全科学 | 423篇 |
废物处理 | 511篇 |
环保管理 | 2199篇 |
综合类 | 4579篇 |
基础理论 | 3977篇 |
环境理论 | 14篇 |
污染及防治 | 4414篇 |
评价与监测 | 790篇 |
社会与环境 | 549篇 |
灾害及防治 | 74篇 |
出版年
2018年 | 219篇 |
2017年 | 222篇 |
2016年 | 295篇 |
2015年 | 260篇 |
2014年 | 321篇 |
2013年 | 1160篇 |
2012年 | 418篇 |
2011年 | 632篇 |
2010年 | 435篇 |
2009年 | 543篇 |
2008年 | 665篇 |
2007年 | 670篇 |
2006年 | 594篇 |
2005年 | 451篇 |
2004年 | 476篇 |
2003年 | 483篇 |
2002年 | 461篇 |
2001年 | 560篇 |
2000年 | 395篇 |
1999年 | 263篇 |
1998年 | 195篇 |
1997年 | 190篇 |
1996年 | 224篇 |
1995年 | 228篇 |
1994年 | 250篇 |
1993年 | 204篇 |
1992年 | 221篇 |
1991年 | 216篇 |
1990年 | 237篇 |
1989年 | 216篇 |
1988年 | 188篇 |
1987年 | 182篇 |
1986年 | 173篇 |
1985年 | 184篇 |
1984年 | 170篇 |
1983年 | 176篇 |
1982年 | 186篇 |
1981年 | 190篇 |
1980年 | 167篇 |
1979年 | 162篇 |
1978年 | 161篇 |
1977年 | 150篇 |
1976年 | 165篇 |
1975年 | 126篇 |
1974年 | 157篇 |
1973年 | 148篇 |
1972年 | 140篇 |
1971年 | 125篇 |
1967年 | 144篇 |
1965年 | 133篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
105.
106.
Association of extinction risk of saproxylic beetles with ecological degradation of forests in Europe 下载免费PDF全文
Sebastian Seibold Roland Brandl Jörn Buse Torsten Hothorn Jürgen Schmidl Simon Thorn Jörg Müller 《Conservation biology》2015,29(2):382-390
To reduce future loss of biodiversity and to allocate conservation funds effectively, the major drivers behind large‐scale extinction processes must be identified. A promising approach is to link the red‐list status of species and specific traits that connect species of functionally important taxa or guilds to resources they rely on. Such traits can be used to detect the influence of anthropogenic ecosystem changes and conservation efforts on species, which allows for practical recommendations for conservation. We modeled the German Red List categories as an ordinal index of extinction risk of 1025 saproxylic beetles with a proportional‐odds linear mixed‐effects model for ordered categorical responses. In this model, we estimated fixed effects for intrinsic traits characterizing species biology, required resources, and distribution with phylogenetically correlated random intercepts. The model also allowed predictions of extinction risk for species with no red‐list category. Our model revealed a higher extinction risk for lowland and large species as well as for species that rely on wood of large diameter, broad‐leaved trees, or open canopy. These results mirror well the ecological degradation of European forests over the last centuries caused by modern forestry, that is the conversion of natural broad‐leaved forests to dense conifer‐dominated forests and the loss of old growth and dead wood. Therefore, conservation activities aimed at saproxylic beetles in all types of forests in Central and Western Europe should focus on lowlands, and habitat management of forest stands should aim at increasing the amount of dead wood of large diameter, dead wood of broad‐leaved trees, and dead wood in sunny areas. 相似文献
107.
108.
Both the ‘cascade model’ of ecosystem service provision and the Driver-Pressure-State-Impact-Response framework individually contribute to the understanding of human–nature interactions in social–ecological systems (SES). Yet, as several points of criticism show, they are limited analytical tools when it comes to reproducing complex cause–effect relationships in such systems. However, in this paper, we point out that by merging the two models, they can mutually enhance their comprehensiveness and overcome their individual conceptual deficits. Therefore we closed a cycle of ecosystem service provision and societal feedback by rethinking and reassembling the core elements of both models. That way, we established a causal sequence apt to describe the causes of change to SES, their effects and their consequences. Finally, to illustrate its functioning we exemplified and discussed our approach based on a case study conducted in the Alpujarra de la Sierra in southern Spain.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-015-0651-y) contains supplementary material, which is available to authorized users. 相似文献109.
Erik Andersson Björn Nykvist Rebecka Malinga Fernando Jaramillo Regina Lindborg 《Ambio》2015,44(1):102-112
In this exploratory study we use existing in situ qualitative and quantitative data on biophysical and social indicators to compare two contrasting Swedish farming systems (low intensity and high intensity) with regard to ecosystem service supply and demand of a broad suite of services. We show that the value (demand) placed on a service is not necessarily connected to the quantity (supply) of the service, most clearly shown for the services recreation, biodiversity, esthetic experience, identity, and cultural heritage. To better capture this complexity we argue for the need to develop portfolios of indicators for different ecosystem services and to further investigate the different aspects of supply and demand. The study indicates that available data are often ill-suited to answer questions about local delivery of services. If ecosystem services are to be included in policy, planning, and management, census data need to be formatted and scaled appropriately. 相似文献
110.
It has been hypothesized that climate warming will allow southern species to advance north and invade northern ecosystems. We review the changes in the Swedish mammal and bird community in boreal forest and alpine tundra since the nineteenth century, as well as suggested drivers of change. Observed changes include (1) range expansion and increased abundance in southern birds, ungulates, and carnivores; (2) range contraction and decline in northern birds and carnivores; and (3) abundance decline or periodically disrupted dynamics in cyclic populations of small and medium-sized mammals and birds. The first warm spell, 1930–1960, stands out as a period of substantial faunal change. However, in addition to climate warming, suggested drivers of change include land use and other anthropogenic factors. We hypothesize all these drivers interacted, primarily favoring southern generalists. Future research should aim to distinguish between effects of climate and land-use change in boreal and tundra ecosystems. 相似文献