全文获取类型
收费全文 | 16107篇 |
免费 | 124篇 |
国内免费 | 77篇 |
专业分类
安全科学 | 335篇 |
废物处理 | 638篇 |
环保管理 | 1915篇 |
综合类 | 3736篇 |
基础理论 | 3636篇 |
环境理论 | 6篇 |
污染及防治 | 3964篇 |
评价与监测 | 1012篇 |
社会与环境 | 1020篇 |
灾害及防治 | 46篇 |
出版年
2022年 | 111篇 |
2021年 | 131篇 |
2019年 | 127篇 |
2018年 | 200篇 |
2017年 | 193篇 |
2016年 | 311篇 |
2015年 | 241篇 |
2014年 | 361篇 |
2013年 | 1088篇 |
2012年 | 408篇 |
2011年 | 614篇 |
2010年 | 472篇 |
2009年 | 554篇 |
2008年 | 635篇 |
2007年 | 673篇 |
2006年 | 603篇 |
2005年 | 506篇 |
2004年 | 532篇 |
2003年 | 519篇 |
2002年 | 490篇 |
2001年 | 622篇 |
2000年 | 394篇 |
1999年 | 295篇 |
1998年 | 186篇 |
1997年 | 204篇 |
1996年 | 224篇 |
1995年 | 233篇 |
1994年 | 233篇 |
1993年 | 218篇 |
1992年 | 198篇 |
1991年 | 207篇 |
1990年 | 198篇 |
1989年 | 169篇 |
1988年 | 168篇 |
1987年 | 154篇 |
1986年 | 153篇 |
1985年 | 148篇 |
1984年 | 169篇 |
1983年 | 167篇 |
1982年 | 172篇 |
1981年 | 144篇 |
1980年 | 132篇 |
1979年 | 123篇 |
1978年 | 134篇 |
1977年 | 115篇 |
1976年 | 103篇 |
1975年 | 107篇 |
1974年 | 118篇 |
1971年 | 98篇 |
1967年 | 101篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
521.
522.
523.
524.
Heat waves and heat-related stresses are increasing environmental concerns in urban areas. The impact of heat waves is dependent on the intensity and duration of each event and on underlying environmental and socio-demographic factors which influence population vulnerability. In order to develop effective adaptation strategies, it is important to develop a method to clearly identify the most vulnerable areas based on these factors. The purpose of this study is to develop and map a heat wave vulnerability index combined with heat exposure analysis to identify areas where interventions can be targeted. The vulnerability index was derived from a principle component analysis of eight key variables that influence heat wave vulnerability. Eight proxy measures of vulnerability were obtained from 2010 census and land-use data for the 1904 census districts of Osaka City. Three principle components explained >77 % of the variance (age, employment and education; social isolation; density and lack of green space). The components were combined and weighted to produce a vulnerability score for each census district. The vulnerability scores ranged from 0 to 106, were categorised into eight vulnerability levels and were overlaid with fine-scale air temperature observations. The resulting output identified the distribution of population vulnerability and exposure. This assessment of vulnerability, combining exposure and sensitivity components, can provide precedent for efficient, targeted action to be taken to reduce the impact of heat waves at present and under climate change. 相似文献
525.
G. S. Kalacheva E. S. Zadereev V. G. Gubanov I. V. Gribovskaya 《Russian Journal of Ecology》2000,31(2):113-117
The chemical composition of water conditioned by colonies ofMoina macrocopa and involved in the regulation of their life cycle was analyzed in comparison with water samples from natural water bodies.
Dechlorinated tap water was used as the control medium. The results showed that metabolism of crustaceans leads to an increase
in the concentrations of phosphorus and nitrogen in all forms, the appearance of protein and carbohydrate fractions, and changes
in the composition of lipid fractions in the water conditioned by their colonies. The contents of all organic components are
very low, which makes their identification difficult. Concentrations of substances identified in the conditioned water do
not exceed those occurring in nature. 相似文献
526.
527.
Tiziano Gomiero Davide Pettenella Giang Phan Trieu Maurizio G. Paoletti 《Environment, Development and Sustainability》2000,2(2):119-142
Vietnam, in the ongoing transition to market economies, has to cope with high rural poverty and a dramatic process of forest loss and environment degradation, particularly in the mountainous regions. The government considers rural poverty as the main cause of environment degradation, associated with slash-and-burn cultivation and to an unclear definition of property rights on forest land. In 1993, the government launched a Forest Land Allocation programme aiming to lease forest lands to individual households and, on this basis, to solve food security problems, halt the increasing environment degradation and preserve the remaining forests.To evaluate the results of this land reform policy, two upland pilot communes have been intensively monitored. The environmental and economic impacts of the forest land reform allocation in the two study areas are presented, after providing a background on the Vietnamese situation of mountain zones. On the basis of these findings, it is discussed as to whether the current forest land allocation process may actually promote local development and natural resources conservation, and under what conditions. Deforestation problems must be tackled also with new macroeconomic policies (e.g. credit programmes to support sustainable agriculture practices) and social policy (e.g. reduction of demographic pressure), together with the reform of the State institutions (e.g. State Forest Enterprises) involved in management of the forest areas. 相似文献
528.
The index of cenotic significance and other indices calculated on its basis were used for revealing specific structural features of zooplanktonic communities in lakes differing in productivity. The results showed that new indices (complexity coefficient, index of cenotic significance of dominant species, and integrated cenotic significance of the zooplankton) strongly correlate with the trophic status of the water body and are more responsive to changes in the structure of the community than the Shannon–Weaver index of species diversity. The results confirm the hypothesis that the structure of zooplankton is simplified in the course of lake eutrophication. 相似文献
529.
Decolorization of Remazol Black-B using a thermotolerant yeast, Kluyveromyces marxianus IMB3 总被引:4,自引:0,他引:4
Meehan C Banat IM McMullan G Nigam P Smyth F Marchant R 《Environment international》2000,26(1-2):75-79
The ability of Kluyveromyces marxianus IMB3 to decolorize Remazol Black-B dye was investigated. The effect of environmental conditions, such as pH and temperature were examined. No noticeable effects on decolorization were observed when pH varied from 3.0-5.5. Maximum colour removal, 98%, was achieved at 37 degrees C. Little or no colour removal was detected when K. marxianus IMB3 was incubated under anaerobic conditions. Further investigation, in which decolorization was monitored under extreme temperatures and low pH (to inhibit growth) and using ten fold dense inoculum, revealed that decolorization was due to biosorption to the yeast cells and not due to a metabolic reaction. 相似文献
530.
G. A. Klevezal A. E. Bakhur A. A. Sokolov V. A. Serezhenkov N. L. Krushinskaya 《Russian Journal of Ecology》2001,32(2):110-116
The results of the electron paramagnetic resonance (EPR) analysis of pure tooth enamel and the data on the radionuclide content in bones were used for estimating the radiation load on reindeer that lived on Wrangel Island in the 1970s and early 1980s. Based on the measurements of the lower jaws, some biological parameters of the Wrangel reindeer population were estimated and compared with those in the Novaya Zemlya and Taimyr populations. Changes in only two of these parameters—the degree of root cementum resorption and animal life span–might be attributed to the effect of the radiation load. 相似文献