全文获取类型
收费全文 | 1784篇 |
免费 | 115篇 |
国内免费 | 699篇 |
专业分类
安全科学 | 154篇 |
废物处理 | 105篇 |
环保管理 | 140篇 |
综合类 | 1039篇 |
基础理论 | 306篇 |
环境理论 | 1篇 |
污染及防治 | 630篇 |
评价与监测 | 79篇 |
社会与环境 | 49篇 |
灾害及防治 | 95篇 |
出版年
2024年 | 6篇 |
2023年 | 36篇 |
2022年 | 78篇 |
2021年 | 80篇 |
2020年 | 56篇 |
2019年 | 50篇 |
2018年 | 60篇 |
2017年 | 98篇 |
2016年 | 88篇 |
2015年 | 77篇 |
2014年 | 147篇 |
2013年 | 171篇 |
2012年 | 169篇 |
2011年 | 130篇 |
2010年 | 133篇 |
2009年 | 120篇 |
2008年 | 143篇 |
2007年 | 117篇 |
2006年 | 109篇 |
2005年 | 84篇 |
2004年 | 38篇 |
2003年 | 72篇 |
2002年 | 67篇 |
2001年 | 58篇 |
2000年 | 51篇 |
1999年 | 62篇 |
1998年 | 56篇 |
1997年 | 47篇 |
1996年 | 44篇 |
1995年 | 38篇 |
1994年 | 23篇 |
1993年 | 27篇 |
1992年 | 20篇 |
1991年 | 13篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有2598条查询结果,搜索用时 316 毫秒
401.
402.
解薇 《防灾科技学院学报》2008,10(3)
四川汶川地震突如其来,它在造成物质毁坏的同时,也给人的心理,特别是对未成年人造成极大的创伤。本文从地震对未成年人造成的心理伤害的内容解析出发,研究了震后未成年人急性应激反应和创伤后应激障碍,并结合地震灾害救灾实际,设计了地震灾害心理救助 相似文献
403.
404.
Abstract There is an obvious departure from the regional equilibrium of developments between the upper and lower reaches of the Pearl River in Guangdong, which resulted in “the effects of contra-geography-grads development”. It is mainly because the upriver mountainous areas have been deeply stuck in industrialization delay and marginalization plights, so that nearly 40 million local people have conceived a dream to get rid of “the vicious circle of poverty” by speeding up industrial development. But the problem is that such industrialization efforts on a large scale in mountainous areas are encountering the bottleneck of environmental capacity that strictly limits industrial emissions along the upper reaches of any water system. As a solution, an institutional arrangement called “the Local Area Quotas for Industrial Emis-sions along the Pearl River” is put forward supposed to give corresponding compensation to the rights of industrial development yielded by some areas with lower environmental capacity through the distribution and trading of IDQs. 相似文献
405.
The maintenance of a timely, reliable and accurate spatial database on current forest ecosystem conditions and changes is
essential to characterize and assess forest resources and support sustainable forest management. Information for such a database
can be obtained only through a continuous forest inventory. The National Forest Continuous Inventory (NFCI) is the first level
of China’s three-tiered inventory system. The NFCI is administered by the State Forestry Administration; data are acquired
by five inventory institutions around the country. Several important components of the database include land type, forest
classification and ageclass/ age-group. The NFCI database in China is constructed based on 5-year inventory periods, resulting
in some of the data not being timely when reports are issued. To address this problem, a forest growth simulation model has
been developed to update the database for years between the periodic inventories. In order to aid in forest plan design and
management, a three-dimensional virtual reality system of forest landscapes for selected units in the database (compartment
or sub-compartment) has also been developed based on Virtual Reality Modeling Language. In addition, a transparent internet
publishing system for a spatial database based on open source WebGIS (UMN Map Server) has been designed and utilized to enhance
public understanding and encourage free participation of interested parties in the development, implementation, and planning
of sustainable forest management. 相似文献
406.
Forest certification is a mechanism involving the regulation of trade of forest products in order to protect forest resources
and improve forest management. Although China had a late start in adopting this process, the country has made good progress
in recent years. As of July 31, 2009, 17 forest management enterprises and more than one million hectares of forests in China
have been certified by the Forest Stewardship Council (FSC). Several major factors affect forest certification in China. The
first set is institutional in nature. Forest management in China is based on centralized national plans and therefore lacks
flexibility. A second factor is public awareness. The importance and value of forest certification are not widely understood
and thus consumers do not make informed choices regarding certified forest products. The third major factor is the cost of
certification. Together these factors have constrained the development of China’s forest certification efforts. However, the
process does have great potential. According to preliminary calculations, if 50% of China’s commercial forests were certified,
the economic cost of forest certification would range from US$0.66–86.63 million while the economic benefits for the forestry
business sector could exceed US$0.66–86.63 million while the economic benefits for the forestry
business sector could exceed US150 million. With continuing progress in forest management practices and the development of
international trade in forest products, it becomes important to improve the forest certification process in China. This can
be achieved by improving the forest management system, constructing and perfecting market access mechanisms for certificated
forest products, and increasing public awareness of environmental protection, forest certification, and their interrelationship. 相似文献
407.
以可持续发展相关理论为基础,利用系统工程的理论和方法建立了河北省县域可持续发展指标体系及其评价标准,并在全省范围应用,对全省136个县(市)可持续发展能力做出了评价。结合评价结果,阐述了河北省县域可持续发展能力的特征,提出了河北省县域可持续发展的方向和思路。 相似文献
408.
409.
Anping Zhang Xuemei Xie Jing Ye Chunmian Lin Xiaoyan Hu 《Environmental Chemistry Letters》2011,9(3):369-373
In recent years, the stereoselective toxicity of chiral organophosphorus pesticides has received increasing attention from
environmental toxicology scientists. In an attempt to explore the stereoselective effects of chiral organophosphorus pesticides
on non-target organisms and enzymes, this work investigated the stereoselective toxicity and inhibition of malathion, malaoxon
and isomalathion on Daphnia magna and on acid α-naphthyl acetate esterase extracted from wheat flour, respectively. Toxicity differences were observed between
the two enantiomers of malathion and malaoxon and among the four stereoisomers of isomalathion in the LC50 values on D. magna and the IC50 values on acid α-naphthyl acetate esterase. Enantiomers with (R)-configuration in all the tested compounds showed
higher toxicity to D. magna than their (S)-forms and racemic forms. Racemic malaoxon and isomalathion showed the strongest inhibition on acid α-naphthyl
acetate esterase compared to their respective enantiomers and stereoisomers. 相似文献
410.
通过盆栽试验探讨了种植皇竹草(Pennisetum hydridum)对阿特拉津污染土壤的修复效果,阿特拉津对皇竹草生长的影响,以及皇竹草对土壤微生物数量的影响,以期为阿特拉津污染土壤的植物修复提供参考。结果表明:在≤200 mg.kg-1质量分数范围以内,种植皇竹草对土壤阿特拉津的初期降解效率比对照明显提高,最大提高了29.64%,达到显著或极显著差异;阿特拉津质量分数在≤200 mg.kg-1范围内对皇竹草株高没有影响,≤50 mg.kg-1质量分数范围内对生物量没有影响,根冠比变化不明显;随阿特拉津质量分数的增加皇竹草根际和非根际土壤中的细菌、真菌、放线菌数量均呈先增加后减少的趋势,在质量分数为100 mg.kg-1时达到最大,根际土壤中细菌和放线菌数量明显高于非根际土壤,真菌数量在根际与非根际土壤中变化不明显。说明种植皇竹草有助于阿特拉津降解效率的提高,且与种植皇竹草后改变了土壤微生物数量及皇竹草的生长状况有关。 相似文献