全文获取类型
收费全文 | 2923篇 |
免费 | 36篇 |
国内免费 | 20篇 |
专业分类
安全科学 | 70篇 |
废物处理 | 111篇 |
环保管理 | 367篇 |
综合类 | 959篇 |
基础理论 | 564篇 |
环境理论 | 4篇 |
污染及防治 | 636篇 |
评价与监测 | 161篇 |
社会与环境 | 100篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 20篇 |
2022年 | 21篇 |
2021年 | 29篇 |
2020年 | 29篇 |
2019年 | 25篇 |
2018年 | 47篇 |
2017年 | 62篇 |
2016年 | 46篇 |
2015年 | 56篇 |
2014年 | 59篇 |
2013年 | 164篇 |
2012年 | 105篇 |
2011年 | 136篇 |
2010年 | 99篇 |
2009年 | 119篇 |
2008年 | 118篇 |
2007年 | 141篇 |
2006年 | 110篇 |
2005年 | 104篇 |
2004年 | 108篇 |
2003年 | 99篇 |
2002年 | 102篇 |
2001年 | 46篇 |
2000年 | 34篇 |
1999年 | 22篇 |
1998年 | 30篇 |
1997年 | 27篇 |
1996年 | 22篇 |
1995年 | 37篇 |
1994年 | 37篇 |
1993年 | 22篇 |
1992年 | 23篇 |
1991年 | 20篇 |
1990年 | 18篇 |
1989年 | 19篇 |
1988年 | 18篇 |
1986年 | 18篇 |
1979年 | 18篇 |
1965年 | 18篇 |
1963年 | 28篇 |
1962年 | 19篇 |
1961年 | 17篇 |
1960年 | 25篇 |
1959年 | 25篇 |
1958年 | 17篇 |
1957年 | 19篇 |
1955年 | 31篇 |
1954年 | 41篇 |
1953年 | 22篇 |
1951年 | 24篇 |
排序方式: 共有2979条查询结果,搜索用时 46 毫秒
51.
52.
53.
Klaassien J. Ganzeveld Annechien van Hagen Martin H. van Agteren Wim de Koning Anton J. M. Schoot Uiterkamp 《Journal of Cleaner Production》1999,7(6):690
Two types of fermented organic waste (trade and industry waste and fruit and vegetable waste) were successfully used as a sole carbon source to produce poly-3-hydroxybutyrate-co-valerate (PHBV) by Ralstonia eutrophus (formerly Alcaligenes eutrophus) via oxygen limitation.The production of PHBV could be optimized by optimizing the oxygen transfer through the fermentor. Thereby, a peak concentration of 1.1 g PHBV per liter cell suspension, 40 w% of cell dry weight, was obtained at an aeration rate of 0.24 mol O2/h·kg biomass. The yield of PHBV on the fatty acid concentration in the organic waste was 0.16 g polymer/g volatile organic matter. The process obtained, compares well with the commercial production process of PHBV based on glucose. 相似文献
54.
Frans J. Los MD PhD Diane Van Opstal Martin P. Schol Johannes L. J. Gaillard Helen Brandenburg Ans M. W. Van Den Ouweland Peter A. In 'T Veld 《黑龙江环境通报》1995,15(12):1155-1159
A prenatally detected case of a rare mosaic tetrasomy 12p/trisomy 12p is reported, presenting as the well-known accessory isochromosome 12p and a supernumerary single 12p marker in 17/24 and 6/24 clones of cultured amniotic fluid cells, respectively. The chromosomal nature of both marker chromosomes was investigated in cultured amniotic fluid cells by fluorescent in situ hybridization with various probes: the 12-centromeric probes pa12H8 and D12Z3, a whole chromosome 12 paint, and the chromosome 12p-specific paint M28. DNA analysis revealed a maternal origin of the extra 12p material. After counselling, the parents requested termination of pregnancy. Inspection and autopsy of the fetus revealed many of the dysmorphisms and internal structural abnormalities of the Pallister–Killian syndrome. 相似文献
55.
56.
57.
58.
59.
60.
Helmut Haberl Christoph Plutzar Karl-Heinz Erb Veronika Gaube Martin Pollheimer Niels B. Schulz 《Agriculture, ecosystems & environment》2005,110(3-4):119-131
The relationship between land-use induced changes in production ecology and avifauna diversity was analysed using a GIS land cover dataset on a 0.25 km × 0.25 km grid covering Austria's national territory. Considering only aboveground processes, the “human appropriation of net primary production” (HANPP = potential NPP − NPPt), actual NPP (NPPact), harvest (NPPh) and NPPt (= NPPact − harvest) were recalculated based on existing datasets. Elevation as well as indicators of land cover heterogeneity and landscape heterogeneity were also considered. Correlation analyses were performed between these potential determinants of avifauna diversity and breeding bird species richness data as well as the percentage of endangered breeding birds included in the Austrian red list. Four spatial scales—0.25 km × 0.25 km, 1 km × 1 km, 4 km × 4 km and 16 × 16 km, were analysed. It was shown that breeding bird species richness was more strongly correlated with production ecological indicators and elevation than with heterogeneity indicators. A residual analysis in which the effect of elevation (a proxy for climate) on species richness and its potential determinants was removed confirmed the importance of the availability of trophic energy (NPP) for bird diversity patterns. The results support the species-energy hypothesis, thus confirming the notion that HANPP could be a useful pressure indicator for biodiversity loss. 相似文献