全文获取类型
收费全文 | 6686篇 |
免费 | 48篇 |
国内免费 | 32篇 |
专业分类
安全科学 | 138篇 |
废物处理 | 295篇 |
环保管理 | 562篇 |
综合类 | 991篇 |
基础理论 | 1386篇 |
环境理论 | 3篇 |
污染及防治 | 1634篇 |
评价与监测 | 556篇 |
社会与环境 | 1172篇 |
灾害及防治 | 29篇 |
出版年
2022年 | 65篇 |
2021年 | 87篇 |
2020年 | 42篇 |
2019年 | 58篇 |
2018年 | 127篇 |
2017年 | 141篇 |
2016年 | 172篇 |
2015年 | 114篇 |
2014年 | 231篇 |
2013年 | 552篇 |
2012年 | 248篇 |
2011年 | 293篇 |
2010年 | 232篇 |
2009年 | 271篇 |
2008年 | 320篇 |
2007年 | 355篇 |
2006年 | 284篇 |
2005年 | 274篇 |
2004年 | 247篇 |
2003年 | 229篇 |
2002年 | 214篇 |
2001年 | 251篇 |
2000年 | 197篇 |
1999年 | 90篇 |
1998年 | 68篇 |
1997年 | 74篇 |
1996年 | 61篇 |
1995年 | 81篇 |
1994年 | 67篇 |
1993年 | 56篇 |
1992年 | 58篇 |
1991年 | 60篇 |
1990年 | 73篇 |
1989年 | 54篇 |
1988年 | 42篇 |
1987年 | 38篇 |
1986年 | 46篇 |
1985年 | 47篇 |
1984年 | 51篇 |
1983年 | 36篇 |
1982年 | 46篇 |
1981年 | 36篇 |
1980年 | 44篇 |
1979年 | 44篇 |
1975年 | 30篇 |
1974年 | 31篇 |
1973年 | 33篇 |
1972年 | 39篇 |
1971年 | 30篇 |
1969年 | 31篇 |
排序方式: 共有6766条查询结果,搜索用时 62 毫秒
21.
I. A. Prokopiev L. N. Poryadina L. A. Konoreva S. V. Chesnokov A. L. Shavarda 《Russian Journal of Ecology》2018,49(5):401-405
The composition and contents of secondary metabolites in Flavocetraria lichens from Eastern Siberia were analyzed using herbarium specimens. Based on the composition of identified metabolites, three F. cucullata chemotypes and two F. nivalis chemotypes were distinguished. Distinct geographic differentiation between the F. cucullata chemotypes was revealed, probably reflecting their adaptation to environmental conditions. The content of usnic acid in F. cucullata thalli was found to correlate with the latitude of growing region. This may be regarded as evidence for a protective role of this metabolite in lichens growing at high latitudes and exposed to excess solar irradiation during the polar day. 相似文献
22.
Oscar Valerio Manjusri Misra Amar K. Mohanty 《Journal of Polymers and the Environment》2018,26(3):1078-1087
Poly(butylene succinate) (PBS) was melt blended with glycerol based polyesters (PGS) synthesized from pure and technical glycerol aiming to improve the impact strength of PBS. It was found that after addition of 30 wt% PGS to PBS its impact strength was significantly increased by 344% (from 31.9 to 110 J/m) and its elongation at break was maintained at 220%. Infrared spectra of the blends showed the presence of hydroxyl groups from the PGS phase suggesting that hydrogen bonding between the phases could be responsible for a good stress transfer and an efficient toughening in the PBS/PGS blends. Scanning electron microscopy imaging showed a good dispersion of PGS phase into PBS with a PGS particle size of 10 μm and less and no agglomeration. Addition of PGS to PBS was shown to be an effective strategy for improvement of PBS impact resistance without serious detrimental effects on its thermal and rheological properties. 相似文献
23.
Zadubrovskiy P. A. Vasina A. V. Novikova E. V. Kondratyuk E. Yu. Matskalo L. L. Novikov E. A. 《Russian Journal of Ecology》2021,52(4):283-289
Russian Journal of Ecology - To test the hypothesis that animals from habitats exposed to high anthropogenic pressure are more successful in adapting to captivity, immature narrow-skulled voles... 相似文献
24.
Population Structure of Sable in the Baikal Mountain Land: Analysis of Genetic and Phenotypic Traits
Russian Journal of Ecology - The genetic and phenotypic structure (according to the fur color) of 14 sable samples from the Baikal mountain land (BML) has been studied by analyzing 257 animals for... 相似文献
25.
26.
Modolo R. C. E. Senff L. Ferreira V. M. Tarelho L. A. C. Moraes C. A. M. 《Journal of Material Cycles and Waste Management》2018,20(2):1006-1015
Journal of Material Cycles and Waste Management - Several types of industrial solid waste have been used as byproducts in the construction and materials industries. Some of the applications seem to... 相似文献
27.
28.
Estimating Remediation and Contaminant Respiration Emissions for Alternatives Comparisons at Petroleum Spill Sites 下载免费PDF全文
Greenhouse gas emissions assessments for site cleanups typically quantify emissions associated with remediation and not those from contaminant biodegradation. Yet, at petroleum spill sites, these emissions can be significant, and some remedial actions can decrease this additional component of the environmental footprint. This article demonstrates an emissions assessment for a hypothetical site, using the following technologies as examples: excavation with disposal to a landfill, light nonaqueous‐phase liquid (LNAPL) recovery with and without recovered product recycling, passive bioventing, and monitored natural attenuation (MNA). While the emissions associated with remediation for LNAPL recovery are greater than the other considered alternatives, this technology is comparable to excavation when a credit associated with product recycling is counted. Passive bioventing, a green remedial alternative, has greater remedial emissions than MNA, but unlike MNA can decrease contaminant‐related emissions by converting subsurface methane to carbon dioxide. For the presented example, passive bioventing has the lowest total emissions of all technologies considered. This illustrates the value in estimating both remediation and contaminant respiration emissions for petroleum spill sites, so that the benefit of green remedial approaches can be quantified at the remedial alternatives selection stage rather than simply as best management practices. ©2015 Wiley Periodicals, Inc. 相似文献
29.
30.
Thomas Abeli Sarah Dalrymple Sandrine Godefroid Andrea Mondoni Jonas V. Müller Graziano Rossi Simone Orsenigo 《Conservation biology》2020,34(2):303-313
The alarming current and predicted species extinction rates have galvanized conservationists in their efforts to avoid future biodiversity losses, but for species extinct in the wild, few options exist. We posed the questions, can these species be restored, and, if so, what role can ex situ plant collections (i.e., botanic gardens, germplasm banks, herbaria) play in the recovery of plant genetic diversity? We reviewed the relevant literature to assess the feasibility of recovering lost plant genetic diversity with using ex situ material and the probability of survival of subsequent translocations. Thirteen attempts to recover species extinct in the wild were found, most of which used material preserved in botanic gardens (12) and seed banks (2). One case of a locally extirpated population was recovered from herbarium material. Eight (60%) of these cases were successful or partially successful translocations of the focal species or population; the other 5 failed or it was too early to determine the outcome. Limiting factors of the use of ex situ source material for the restoration of plant genetic diversity in the wild include the scarcity of source material, low viability and reduced longevity of the material, low genetic variation, lack of evolution (especially for material stored in germplasm banks and herbaria), and socioeconomic factors. However, modern collecting practices present opportunities for plant conservation, such as improved collecting protocols and improved cultivation and storage conditions. Our findings suggest that all types of ex situ collections may contribute effectively to plant species conservation if their use is informed by a thorough understanding of the aforementioned problems. We conclude that the recovery of plant species currently classified as extinct in the wild is not 100% successful, and the possibility of successful reintroduction should not be used to justify insufficient in situ conservation. 相似文献