全文获取类型
收费全文 | 9661篇 |
免费 | 0篇 |
专业分类
废物处理 | 772篇 |
环保管理 | 1207篇 |
综合类 | 945篇 |
基础理论 | 3108篇 |
污染及防治 | 1727篇 |
评价与监测 | 1006篇 |
社会与环境 | 896篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 1473篇 |
2017年 | 1371篇 |
2016年 | 1194篇 |
2015年 | 125篇 |
2014年 | 15篇 |
2013年 | 7篇 |
2012年 | 460篇 |
2011年 | 1338篇 |
2010年 | 691篇 |
2009年 | 597篇 |
2008年 | 878篇 |
2007年 | 1226篇 |
2006年 | 3篇 |
2005年 | 23篇 |
2004年 | 34篇 |
2003年 | 62篇 |
2002年 | 98篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 2篇 |
1998年 | 9篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1935年 | 2篇 |
排序方式: 共有9661条查询结果,搜索用时 15 毫秒
991.
Spectrofluorimetric study of the ageing of mixtions used in the gildings of mediaeval wall paintings
Mounier A Belin C Daniel F 《Environmental science and pollution research international》2011,18(5):772-782
Introduction
In the Middle Ages, we could find gildings on mural paintings. Gold, silver or tin leaves were applied according to distemper or mixtion technique. For the first one, a binder as glue is necessary, and for the second, a lipidic binder is used to stick the metallic leaf. Studies of gildings materials characterization show that the mixtion technique, with a mordant, is the most common. Linseed oil seems to be the binder used. It is always mixed with a siccative agent as lead. Because of bad conditions of conservation, the gildings do not resist anymore, only remain traces of metal or the adhesive under-layer. Thanks to the binder fluorescence, we can nowadays detect ancient gildings. 相似文献992.
Rundqvist S Hedenås H Sandström A Emanuelsson U Eriksson H Jonasson C Callaghan TV 《Ambio》2011,40(6):683-692
Shrubs and trees are expected to expand in the sub-Arctic due to global warming. Our study was conducted in Abisko, sub-arctic
Sweden. We recorded the change in coverage of shrub and tree species over a 32– to 34-year period, in three 50 × 50 m plots;
in the alpine-tree-line ecotone. The cover of shrubs and trees (<3.5 cm diameter at breast height) were estimated during 2009–2010
and compared with historical documentation from 1976 to 1977. Similarly, all tree stems (≥3.5 cm) were noted and positions
determined. There has been a substantial increase of cover of shrubs and trees, particularly dwarf birch (Betula nana), and mountain birch (Betula pubescens ssp. czerepanovii), and an establishment of aspen (Populus tremula). The other species willows (Salix spp.), juniper (Juniperus communis), and rowan (Sorbus aucuparia) revealed inconsistent changes among the plots. Although this study was unable to identify the causes for the change in shrubs
and small trees, they are consistent with anticipated changes due to climate change and reduced herbivory. 相似文献
993.
Julius H. Kotir 《Environment, Development and Sustainability》2011,13(3):587-605
Sub-Saharan Africa has been portrayed as the most vulnerable region to the impacts of global climate change because of its
reliance on agriculture which is highly sensitive to weather and climate variables such as temperature, precipitation, and
light and extreme events and low capacity for adaptation. This article reviews evidence on the scope and nature of the climate
change challenge; and assesses the impact of climate change on agriculture and food security in Sub-Saharan Africa. From the
review, it is apparent that the climate in Africa is already exhibiting significant changes, evident by changes in average
temperature, change in amount of rainfall and patterns and the prevalence of frequency and intensity of weather extremes.
The review also revealed that although uncertainties exist with regards to the magnitude of impacts, climate will negatively
affect agricultural production in Sub-Saharan Africa. Specifically, as result of current and expected climate change, the
area suitable for agriculture, the length of growing seasons and yield potential, particularly along the margins of semi-arid
and arid areas, are expected to decrease. These impacts will affect all components of food security: food availability, food accessibility, food utilisation and food stability and hence increase the risk of hunger in the region. The review thus confirms the general consensus that Sub-Saharan Africa
is the most vulnerable region to climate change. It suggests that, policymakers and development agencies should focus on formulating
and implementing policies and programmes that promote farm level adaptation strategies currently being practiced by farmers
across the region. 相似文献
994.
Ben-Shlomo R Shanas U 《Environmental science and pollution research international》2011,18(8):1264-1269
Purpose
We tested the genetic diversity in wild mice (Mus musculus domesticus) inhabiting the asbestos-polluted area as a model for the long-term mutagenic effect of asbestos. Hazardous effects of deposited asbestos persist in the environment because of low rate of fiber disintegration. The upper layers of the soil in the vicinity of a former asbestos factory are nearly “saturated” with asbestos fibers and dust. Natural populations of mice dwell in this area and are constantly exposed to asbestos fibers. 相似文献995.
996.
Kirk R. Vincent Jonathan M. Friedman Eleanor R. Griffin 《Environmental management》2009,44(2):218-227
Removal of nonnative riparian trees is accelerating to conserve water and improve habitat for native species. Widespread control
of dominant species, however, can lead to unintended erosion. Helicopter herbicide application in 2003 along a 12-km reach
of the Rio Puerco, New Mexico, eliminated the target invasive species saltcedar (Tamarix spp.), which dominated the floodplain, as well as the native species sandbar willow (Salix exigua Nuttall), which occurred as a fringe along the channel. Herbicide application initiated a natural experiment testing the
importance of riparian vegetation for bank stability along this data-rich river. A flood three years later eroded about 680,000 m3 of sediment, increasing mean channel width of the sprayed reach by 84%. Erosion upstream and downstream from the sprayed
reach during this flood was inconsequential. Sand eroded from channel banks was transported an average of 5 km downstream
and deposited on the floodplain and channel bed. Although vegetation was killed across the floodplain in the sprayed reach,
erosion was almost entirely confined to the channel banks. The absence of dense, flexible woody stems on the banks reduced
drag on the flow, leading to high shear stress at the toe of the banks, fluvial erosion, bank undercutting, and mass failure.
The potential for increased erosion must be included in consideration of phreatophyte control projects. 相似文献
997.
Understanding how setting attributes influence the nature of the visitor experience is crucial to effective recreation management.
Highly influential attributes are useful indicators to monitor within a planning framework, such as Limits of Acceptable Change.
This study sought to identify the setting attributes perceived to have the most profound effect on the ability to have “a
real wilderness experience” and to assess the degree to which attribute importance varied with situational context and visitor
characteristics. To this end, exiting hikers were surveyed at moderate and very high use trailheads in Alpine Lakes Wilderness,
WA (USA), and Three Sisters Wilderness, OR (USA). They were asked about the degree to which encountering varying levels of
different setting attributes would add to or detract from their experience. Attributes with the largest range of effect on
experience, based on evaluations of different levels, were considered most important. The most influential attributes were
litter and several types of campsite interaction—people walking through camp and number of other groups camping close by.
The perceived importance of setting attributes did not vary much between wilderness locations with substantially different
use levels, suggesting that conclusions are robust and generalizable across wilderness areas. There also was little difference
in the perceptions of day and overnight visitors. In contrast, we found substantial variation in the perceived importance
of setting attributes with variation in wilderness experience, knowledge, attachment, and motivation. Our results validate
the emphasis of many wilderness management plans on indicators of social interaction, such as number of encounters. 相似文献
998.
999.
Vernon G. Thomas 《The Environmentalist》2010,30(2):206-210
Lead from spent ammunition causes preventable lead exposure in wildlife and humans that may ingest it. Nontoxic substitutes
for lead ammunition exist but are not adopted widely because of hunter opposition. Other forms of lead exposure in the human
environment have been heavily regulated because there is no safe level of exposure. The use of lead ammunition should be regulated
similarly to protect wildlife from this common disease. 相似文献
1000.
Fuminori Hashihama Haruko Umeda Chiaki Hamada Sakae Kudoh Toru Hirawake Kazuhiko Satoh Mitsuo Fukuchi Yasuhiro Kashino 《Marine Biology》2010,157(10):2263-2278
In high-latitude waters such as the Southern Ocean, the primary production of phytoplankton supports the ecosystem. To understand
the photo-acclimation strategy of such phytoplankton within cold environments, the vertical distribution profile of photosynthetic
pigments was analyzed in the Southern Ocean. Samples were taken along 110°E during the austral summer, and along 150°E and
around the edge of the seasonal sea ice of the Antarctic Continent during the austral autumn. Pigment extraction methods were
optimized for these samples. The standing crop of chlorophyll a was larger in the region along the edge of the seasonal sea ice than at sampling stations in open ocean areas. Chlorophyll
concentration seemed to be dependent on the formation of thermo- and haloclines along the edge of the seasonal sea ice, but
not in the open ocean where such clines are less pronounced. The marker pigments fucoxanthin and/or 19′-hexanoyloxyfucoxanthin
were dominant at most sampling stations throughout the water column, while other marker pigments such as alloxanthin were
quite low. This indicated that diatoms and/or haptophytes were the major phytoplankton in this area. Comparison of the relative
ratio of fucoxanthin with that of 19′-hexanoyloxyfucoxanthin allowed some stations to be characterized as either diatom-dominant
or haptophyte-dominant. The relative ratio of xanthophyll-cycle pigments (diadinoxanthin plus diatoxanthin) to chlorophyll
a was high in surface waters and decreased gradually with depth. This suggests that near the ice edge during summer in the
Southern Ocean, both diatoms and haptophytes acclimate to their light environments to protect their photosystems under high-light
conditions. 相似文献