全文获取类型
收费全文 | 1100篇 |
免费 | 30篇 |
国内免费 | 24篇 |
专业分类
安全科学 | 52篇 |
环保管理 | 263篇 |
综合类 | 460篇 |
基础理论 | 147篇 |
环境理论 | 1篇 |
污染及防治 | 57篇 |
评价与监测 | 115篇 |
社会与环境 | 46篇 |
灾害及防治 | 13篇 |
出版年
2024年 | 3篇 |
2023年 | 11篇 |
2022年 | 12篇 |
2021年 | 24篇 |
2020年 | 54篇 |
2019年 | 12篇 |
2018年 | 14篇 |
2017年 | 31篇 |
2016年 | 37篇 |
2015年 | 25篇 |
2014年 | 49篇 |
2013年 | 41篇 |
2012年 | 38篇 |
2011年 | 74篇 |
2010年 | 41篇 |
2009年 | 86篇 |
2008年 | 60篇 |
2007年 | 64篇 |
2006年 | 60篇 |
2005年 | 37篇 |
2004年 | 33篇 |
2003年 | 52篇 |
2002年 | 47篇 |
2001年 | 29篇 |
2000年 | 41篇 |
1999年 | 35篇 |
1998年 | 25篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1995年 | 21篇 |
1994年 | 8篇 |
1993年 | 19篇 |
1992年 | 13篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1977年 | 1篇 |
排序方式: 共有1154条查询结果,搜索用时 250 毫秒
861.
Ecotoxicological effects of typical personal care products on seed germination and seedling development of wheat (Triticum aestivum L.) 总被引:1,自引:0,他引:1
Biochemical responses of wheat (Triticum aestivum L.) seedlings stressed by two typical personal care products (PCPs) – triclosan (TCS) and galaxolide (HHCB) were experimentally investigated to assess their ecological risks. The results showed that wheat shoot and root elongation was significantly inhibited by 50–250 mg L−1 TCS and HHCB. Wheat roots were sensitive to TCS, while shoots were sensitive to HHCB. The median effect concentration (EC50) of TCS and HHCB based on the inhibition of their sensitive sites were 147.8 and 143.4 mg L−1, respectively. Moreover, the damage of wheat seedlings treated by low concentration of TCS and HHCB during a long period cannot be neglected. After a 21-d exposure, 0.2–3.0 mg L−1 TCS and HHCB treatment caused the damage to the accumulation of chlorophyll (CHL), the synthesis of soluble protein (SP), and the activity of peroxidase (POD) and superoxide dismutases (SOD) in different degree. However, different changing trends of these physiological indexes treated by different PCPs were observed after 7-d to 14-d exposures, especially the activity of POD and SOD. The activity of POD and SOD in wheat leaves and roots decreased with an increase in the concentration of TCS and the exposure time. However, the enzyme activities in wheat leaves treated by 0.2–3.0 mg L−1 HHCB increased after a 14-d exposure, and with the prolongation of exposure time, the enzyme activities significantly decreased. The variations in these physiological indexes of wheat could be considered as good biomarkers of serious stress by TCS and HHCB in the environment. 相似文献
862.
A Rapid Method to Score Stream Reaches Based on the Overall Performance of Their Main Ecological Functions 总被引:1,自引:1,他引:0
David K. Rowe Stephanie Parkyn John Quinn Kevin Collier Chris Hatton Michael K. Joy John Maxted Stephen Moore 《Environmental management》2009,43(6):1287-1300
A method was developed to score the ecological condition of first- to third-order stream reaches in the Auckland region of
New Zealand based on the performance of their key ecological functions. Such a method is required by consultants and resource
managers to quantify the reduction in ecological condition of a modified stream reach relative to its unmodified state. This
is a fundamental precursor for the determination of fair environmental compensation for achieving no-net-loss in overall stream
ecological value. Field testing and subsequent use of the method indicated that it provides a useful measure of ecological
condition related to the performance of stream ecological functions. It is relatively simple to apply compared to a full ecological
study, is quick to use, and allows identification of the degree of impairment of each of the key ecological functions. The
scoring system was designed so that future improvements in the measurement of stream functions can be incorporated into it.
Although the methodology was specifically designed for Auckland streams, the principles can be readily adapted to other regions
and stream types. 相似文献
863.
The response of epiphytic lichens to air pollution and subsets of ecological predictors: a case study from the Italian Prealps 总被引:1,自引:0,他引:1
Cristofolini F Giordani P Gottardini E Modenesi P 《Environmental pollution (Barking, Essex : 1987)》2008,151(2):308-317
We investigated the response of epiphytic lichens to air pollution, against the background of other ecological predictors in a prealpine heterogeneous area, using Non-Parametric Multiplicative Regression (NPMR). The best NPMR model for total lichen diversity according to N environmental predictors at tree level has a cross R(2)=0.709. It includes 10 variables, belonging to three different subsets of factors: two pollution-related factors (distance in meters from the road and from the cement factory); four stand-related (habitat, heat index, LAI and elevation) and four substrate-related factors (inclination, circumference and texture and tree species). Considering separately the effects of each subset on lichen diversity, substrate- and stand-related factors produce good models with similar cross R(2) (0.490 and 0.500, respectively), whereas pollution-related factors produce a model with a lower cross R(2) (0.340). Hence, we provide information to investigate the applicability of lichen biomonitoring to complex heterogeneous areas where standardized protocols are not reliable. 相似文献
864.
China’s new Classification-Based Forest Management (CFM) is a two-class system, including Commodity Forest (CoF) and Ecological
Welfare Forest (EWF) lands, so named according to differences in their distinct functions and services. The purposes of CFM
are to improve forestry economic systems, strengthen resource management in a market economy, ease the conflicts between wood
demands and public welfare, and meet the diversified needs for forest services in China. The formative process of China’s
CFM has involved a series of trials and revisions. China’s central government accelerated the reform of CFM in the year 2000
and completed the final version in 2003. CFM was implemented at the provincial level with the aid of subsidies from the central
government. About a quarter of the forestland in China was approved as National EWF lands by the State Forestry Administration
in 2006 and 2007. Logging is prohibited on National EWF lands, and their landowners or managers receive subsidies of about
70 RMB (US$10) per hectare from the central government. CFM represents a new forestry strategy in China and its implementation
inevitably faces challenges in promoting the understanding of forest ecological services, generalizing nationwide criteria
for identifying EWF and CoF lands, setting up forest-specific compensation mechanisms for ecological benefits, enhancing the
knowledge of administrators and the general public about CFM, and sustaining EWF lands under China’s current forestland tenure
system. CFM does, however, offer a viable pathway toward sustainable forest management in China. 相似文献
865.
866.
草原生态补偿:减畜和补偿的对等关系 总被引:3,自引:0,他引:3
中国草原生态补偿是通过补助和奖励的政策手段达到减畜和草畜平衡的政策目标,最终使牧民收入不减少的条件下草原退化得到减缓。论文首先从理论上提出一个分析草原生态补偿减畜和补偿对等关系的框架,然后以内蒙古四子王旗查干补力格苏木为例,对草原生态补偿减畜和补偿的对等关系进行了实证分析。实证分析结果表明:因为超载情况存在空间异质性和牧户差异性,实际的超载率较统计的超载率被低估了。补偿在区域总量上是不足够的,维持区域总量补偿足够的草畜平衡奖励标准应为28.5元/hm2。减畜和补偿存在严重的不对等关系,47.9%的资金给了那些不需要减畜的牧户,减畜比例0%;5.5%的资金给了那些需要减畜也愿意减畜的牧户,减畜比例1.2%;46.6%的资金给了那些需要减畜但只愿意部分减畜的牧户,减畜比例98.8%。预期能够实现的减畜比例仅为8.3%,由于牧户超载程度存在显著的差异,预期能够实现的减畜比例对草畜平衡奖励标准和每羊单位损失均不敏感。为了达到草原生态保护的目的,保障减畜的有效达成,应该将超载程度纳入草畜平衡奖励的政策设计中。中小牧户是草原超载的主体,"将超载程度纳入草畜平衡奖励的政策设计"的真正含义是"将草畜平衡奖励向中小牧户做出适当倾斜"。"超越"草畜平衡奖励,减少中小牧户的数量,扩大牧户的草场经营规模,促进牧区牧户的适度规模经营才是实现草原可持续发展的出路所在。 相似文献
867.
本文以广州市为例,分析认为绿色信贷制度将在生态农业、生态工业、能源、基础设施建设、消费信贷等领域发挥重要作用,进而防控污染,保护资源环境,建设美丽幸福中国,保障国民健康,增进民生福祉。 相似文献
868.
869.
870.
Polluting substances are spread as a consequence of the construction and use of roads. This article provides a summary of
the substances with which traffic pollutes the environment on a local, regional and global level. The mechanisms of dispersion
of pollutants to soil and groundwater are described. Based on environmental quality requirements established in rules and
regulations in the Netherlands, the paper discusses mitigating measures necessary to limit the distribution of pollutants
along highways. Most of the data in this article come from original research carried out by or by order of the Road and Hydraulic
Institute. For comparison, other data from the Netherlands have been included. It is shown that source-oriented measures (volume
and technical) will have more effect on environmental quality than measures with regard to treating runoff. The use of porous
asphalt instead of nonporous asphalt on highways in the Netherlands has environmental benefits. The article also pays attention
to combined use of the roadside verges for treatment of runoff using ecological engineering techniques in the form of natural
processes in helophyte filter systems in combination with enhancement of ecological values along highways. 相似文献