全文获取类型
收费全文 | 2365篇 |
免费 | 271篇 |
国内免费 | 703篇 |
专业分类
安全科学 | 404篇 |
废物处理 | 36篇 |
环保管理 | 254篇 |
综合类 | 1502篇 |
基础理论 | 409篇 |
环境理论 | 1篇 |
污染及防治 | 129篇 |
评价与监测 | 57篇 |
社会与环境 | 359篇 |
灾害及防治 | 188篇 |
出版年
2024年 | 18篇 |
2023年 | 65篇 |
2022年 | 132篇 |
2021年 | 124篇 |
2020年 | 127篇 |
2019年 | 128篇 |
2018年 | 106篇 |
2017年 | 130篇 |
2016年 | 134篇 |
2015年 | 128篇 |
2014年 | 113篇 |
2013年 | 158篇 |
2012年 | 207篇 |
2011年 | 217篇 |
2010年 | 156篇 |
2009年 | 158篇 |
2008年 | 123篇 |
2007年 | 173篇 |
2006年 | 138篇 |
2005年 | 143篇 |
2004年 | 104篇 |
2003年 | 98篇 |
2002年 | 68篇 |
2001年 | 52篇 |
2000年 | 66篇 |
1999年 | 43篇 |
1998年 | 40篇 |
1997年 | 38篇 |
1996年 | 25篇 |
1995年 | 24篇 |
1994年 | 31篇 |
1993年 | 13篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 12篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有3339条查询结果,搜索用时 593 毫秒
591.
Sajjad Haider Rab Nawaz Muzammil Anjum Tahir Haneef Vipin Kumar Oad Salah Uddinkhan Rawaiz Khan Muhammad Aqif 《Frontiers of Environmental Science & Engineering》2023,17(9):111
592.
Kostanjsek R Lapanje A Drobne D Perović S Perović A Zidar P Strus J Hollert H Karaman G 《Environmental science and pollution research international》2005,12(6):361-368
- Goal, Scope, Background. Lake Skadar is the largest lake in Balkan Peninsula, located on the Montenegro-Albanian border. The
unique features of the lake and wide range of endemic and rare or endangered plant and animal species resulted in the classification
of the Skadar as a wetland site of international significance. In spite of its importance the Lake is influenced by inflowing
waters from river Morača and other regional rivers contaminated by the industry, municipal and agricultural activities in
the area. Therefore, the Lake has been subject of various physical, chemical, biological and toxicological examinations. However,
community-level analyses are most relevant to assess the effect of stressors on aquatic ecosystems. In the present study bacterial
community structure among differently polluted sites of the lake was compared by genetic fingerprinting technique.
Methods Water and sediment samples were collected from five differently polluted sampling sites on the Lake Skadar in spring and
autumn of the same year. The bacterial community structure in the samples was characterized and compared by temporal temperature
gel electrophoresis (TTGE) analysis of polymerase chain reaction-amplified bacterial 16S rRNA genes.
Results and Discussion The TTGE analysis resulted in many distinguishable and reproducible band patterns, allowing reliable comparison of bacterial
communities among sampling sites. Results on the bacterial community structure revealed that three of the selected locations
can be considered as sites that have not shown any pollution degradation determined by our method, due to similar structure
of bacterial community in the sediment samples. On the other hand, significant shifts in bacterial community structure in
the mouth of the river Morača and Plavnica were shown. Since the results coincide with some of the bioassays and chemical
analysis performed previously, the changes in bacterial community structure are explained as an effect of antropogenic pollution
on the lake ecosystem by waters of river Morača and stream Plavnica.
Conclusion The TTGE has proven to be an efficient and reliable method to monitor bacterial dynamics and community shifts in aquatic
environment, especially in the sediments. Within the variety of environmental quality assessments the use of TTGE analyses
of bacterial community is strongly recommended, particularly as an initial investigation. However, in any conclusion on the
state of the environment, the TTGE results should be combined to some other biological, chemical and hydrological data.
Recommendation and Outlook Since prokaryotes are a crucial group of organisms in the biosphere, the ecosystem function studies are largely based on
bacterial communities. Therefore, bacterial community structure analysis should be a part of an integrated weight of evidence
approach in pollution assessment. In case of Triad approach, consisting of chemical analyses, bioassays, and community studies
in the field, the TTGE bacterial community structure analyses should be placed in the later Triad leg. In comparison to other
community studies, based on various biotic indices, the TTGE bacterial community analysis has proven to be very sensitive,
reliable and less time consuming. 相似文献
593.
于2013年5月至10月对密云水库上游河流中大型底栖无脊椎动物(以下简称底栖动物)进行了采样调查。结果表明,采集到的底栖动物隶属于4门10纲16目45科,其中以节肢动物种类最多,占总数的80%,且水生昆虫占总数的67%,出现频率最高的是节肢动物门蜉蝣目蜉蝣科的昆虫,出现频率达87%;从分布来看,白河流域采集到的底栖动物种类最多、密度最高,而潮河流域采集到的底栖动物生物量最大;以底栖动物为指示生物的水质评价结果显示,密云水库上游河流中50%采样点的水质为Ⅰ级(清洁),其余50%为Ⅱ级(轻微污染),水质整体较好,与现场生境调查和水质监测的结果相吻合。 相似文献
594.
595.
某耗能减震框肢剪力墙转换结构分析 总被引:1,自引:0,他引:1
采用复合型铅粘弹性阻尼器对带转换层框肢剪力墙结构的某酒店进行了耗能减震设计,对耗能减震结构和钢支撑结构进行了对比分析,包括反应谱和局部非线性多遇地震作用和罕遇地震作用下的时程分析。结果表明,底部框架结构布置复合型铅粘弹性阻尼器后,在多遇和罕遇地震情况下层间位移能满足《建筑抗震设计规范》要求,并且采用耗能减震结构能优化整体结构,不会对转换层上部结构产生不利的影响,能更好地改善结构的抗震性能。 相似文献
596.
597.
598.
599.
600.