全文获取类型
收费全文 | 17457篇 |
免费 | 1220篇 |
国内免费 | 3197篇 |
专业分类
安全科学 | 2601篇 |
废物处理 | 355篇 |
环保管理 | 2784篇 |
综合类 | 10271篇 |
基础理论 | 1571篇 |
环境理论 | 10篇 |
污染及防治 | 1538篇 |
评价与监测 | 782篇 |
社会与环境 | 1115篇 |
灾害及防治 | 847篇 |
出版年
2024年 | 80篇 |
2023年 | 354篇 |
2022年 | 571篇 |
2021年 | 698篇 |
2020年 | 715篇 |
2019年 | 552篇 |
2018年 | 471篇 |
2017年 | 645篇 |
2016年 | 748篇 |
2015年 | 758篇 |
2014年 | 817篇 |
2013年 | 1013篇 |
2012年 | 1170篇 |
2011年 | 1290篇 |
2010年 | 900篇 |
2009年 | 998篇 |
2008年 | 749篇 |
2007年 | 1157篇 |
2006年 | 1162篇 |
2005年 | 1034篇 |
2004年 | 906篇 |
2003年 | 845篇 |
2002年 | 726篇 |
2001年 | 622篇 |
2000年 | 566篇 |
1999年 | 531篇 |
1998年 | 355篇 |
1997年 | 290篇 |
1996年 | 199篇 |
1995年 | 194篇 |
1994年 | 165篇 |
1993年 | 151篇 |
1992年 | 99篇 |
1991年 | 61篇 |
1990年 | 44篇 |
1989年 | 24篇 |
1988年 | 32篇 |
1987年 | 17篇 |
1986年 | 12篇 |
1985年 | 14篇 |
1984年 | 24篇 |
1983年 | 20篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 15篇 |
1979年 | 14篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1971年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
491.
ABSTRACTThis article contributes to efforts to validate a common set of parameters and principles of sustainable agriculture. Comparisons between alternative forms of sustainable agriculture and rural-to-urban community resilience are investigated. Conclusions are drawn between multiple sustainable/alternative agriculture systems and evaluated. A set of common baseline parameters and principles is proposed as a method of evolving a common structural framework for strengthening sustainability of agriculture and rural contexts. Concepts of rural-to-urban community sustainability are proposed, supporting sustainable agriculture contexts as rural and urban. In the twenty-first century, agriculture is becoming more diversified and less typified as a rural occupation. Urban agriculture is expanding as the need for fresh, affordable, accessible agriculture produce increases in urban areas. Evidence supports symbiotic relationships between sustainable agriculture and rural/urban communities, although some claim this relationship has not been clearly defined.This article investigates sustainable agriculture from two perspectives. We ask ‘what are common parameters and principles of the various forms of sustainable agriculture,’ and ‘why urban-to-rural context.’ Organic agriculture parameters and principles are proposed as a conceptual framework toward establishing baseline parameters and principles for sustainable agriculture. Best management parameters of urban and rural sustainable agriculture in the United States and the United Kingdom are examined for their potential to develop a strengthening framework of parameters and principles of agriculture and rural-to-urban sustainability. These results are compared and evaluated for their effectiveness in redefining current sustainable agriculture practices, and their value in strengthening sustainable agriculture symbiosis with rural-to-urban community systems. 相似文献
492.
ABSTRACTSmall and medium-sized enterprises (SMEs) have a substantial role in the economy and job creation, but they are a remarkable source of environmental impacts. SMEs often lack skills and resources to compile environmental impact assessments; Streamlined Life Cycle Analysis (LCA) can provide efficient tools for this. An application of streamlined LCA relying heavily on database data, LCA clinic, was developed and tested on 23 SMEs in Finland. The climate change impacts were mainly caused by the production of raw materials, electricity and heating, whereas packaging and transportation were not influential. A significant amount of emissions were indirect, i.e. caused by production of raw materials. Thus, decreasing emissions from raw material production or selecting raw materials with a smaller environmental load could be a more efficient way to decrease emissions than reducing direct emissions such as those from electricity use. Lack of data in the LCA-databases was considered a challenge. An access to regionally customised datasets is important for the implementation of LCA clinics. Company feedback indicated that LCA clinics were useful in climate-friendly product design and increased environmental awareness, but did not lead to immediate actions to reduce emissions because of inadequate investment capabilities. Company managers had limited possibilities to use the results in marketing as comparative assessments would require a full LCA. Many company managers were willing to pay a fee sufficient to cover the costs of an LCA clinic, but some considered that the costs should be covered by external funding sources. 相似文献
493.
A. S. van Jaarsveld 《国际发展与全球生态学杂志》2013,20(2):15-37
SUMMARY A quantitative method which can be used to gauge the sustainability of existing socio-cultural, economic and environmental constructs is proposed. An underlying assumption of the approach is that a co-evolutionary relationship exists between social, cultural, economic and environmental systems and that these cannot be addressed in a reductionist and deterministic manner. The method focuses on both broad trends and patterns of variance in a multivariate data matrix, it allows the identification of dominant trends as well as underlying tensions, does not treat socio-cultural, economic and environmental heterogeneity as statistical noise and can be applied at different administrative scales. Furthermore, it may be used to identify potential sources of human insecurity, factors that may affect the probability of positive human survival, developmental patterns at odds with the established values system of civil society that can be targeted for political action, and to inform public debate. In addition, the method can be used to identify unexpected synergies between variables and may serve as an early warning system for regional planners. 相似文献
494.
Characterisation and identification of carbofuran-utilising bacteria isolated from agricultural soil
R. A.I. Abou-Shanab M. A. Khalafallah N. F. Emam M. A. Aly S. A. Abou-Sdera I. A. Matter 《Chemistry and Ecology》2013,29(2):193-203
A total of 96 bacterial cultures were isolated from soil. Seventeen bacterial isolates were selected following their cultivation on solid media containing 100 mg · L?1 carbofuran as the sole source of carbon and nitrogen. Of the 17 isolates, 10F, 11M, 17N, 23B and 26M were specifically chosen because of their relatively higher growth efficiency and genetic diversity based on Box-polymerase chain reaction analysis. These bacterial cultures had 16S rRNA gene sequences that were most similar to Acinetobacter baumannii (10F), Agrobacterium tumefaciens (11M), Ochrobactrum anthropi (17N), Escherichia coli (23B) and Agrobacterium tumefaciens (26M) with 97, 95, 93, 95 and 94% similarity in their 16S rDNA gene sequence, respectively. Degradation rates of carbofuran in soil inoculated with these isolates were 1.9, 1.5, 1.6, 1.7 and 1.6 times, respectively, faster in comparison with uninoculated soil after 10 days of incubation. The maximum degradation rates of carbofuran (45 and 91%) were detected in soil inoculated with A. baumannii (10F) after 10 and 20 days’ incubation, respectively. These data indicate that these isolates may have the potential for use in bioremediation of pesticide contaminated soil. 相似文献
495.
Effects of sepiolite and biochar on microbial diversity in acid red soil from southern China 总被引:1,自引:0,他引:1
Sepiolite and biochar can immobilize heavy metals and organic pollutants in soil effectively, but their impact on the soil microbial community and diversity is still unclear. High-throughput Illumina MiSeq method was used to study the effects of sepiolite and biochar on the diversity of microbial communities in acid red soil amended with cadmium and atrazine. A total of 47,472 microbiological Operational Taxonomic Units (OTUs) were found in all the treated soil samples. Sepiolite and biochar enriched the diversity of soil microbes at different classification levels and OTUs, but the effect of biochar was stronger than that of sepiolite. A Venn diagram showed that compared with other treatments, adding 2% biochar could promote the growth of specific microbes, which is better than the case for 5% biochar. The heat map of species abundance cluster showed that the dominant microbes in soil were different for different treatment doses of sepiolite and biochar. Among all the soil treatments, the top ten dominant bacterial phyla (from high to low dominance) were: Actinobacteria, Proteobacteria, Firmicutes, Bacteroidetes, Acidobacteria, Gemmatimonadetes, Chloroflexi, Planctomycetes, Cyanobacteria, and Verrucomicrobia. The addition of sepiolite and biochar promoted the restoration of the microbial community diversity in contaminated soil. 相似文献
496.
Abstract Spatial and temporal variations and the factors influencing primary production have been studied in three different mangrove waters (Pichavaram, Ennore Creek and Adyar Estuary) of South India characterised by different anthropogenic impacts. the gross primary productivity in the unpolluted Pichavaram mangrove was 113 g Cm?2yr?1 exhibiting natural variability with the environmental forcing factors. Human activities have elevated primary productivity in the Ennore Creek mangrove (157g Cm?2yr?1) primarily through the direct discharge of fertilizer effluents. By contrast, a combination of domestic and industrial effluent discharges into the Adyar Estuary mangrove has considerably reduced phytoplankton primary productivity 83g Cm?2yr?1 the Redfield N: P ratio varies from 0.96 N: 1P at Ennore Creek, 1.75N: 1P at Adyar Estuary to 15.2 N: 1P at Pichavaram mangroves. This suggests that the Pichavaram mangroves represent a well equilibrated ecosystem with N: P ratio close to steady-state values in contrast to the anthropogenically altered mangrove ecosystems studied. Results show a significant temporal variability in nutrient concentration in the three mangrove areas. Distinct differences in nutrient concentrations between the dry and the wet seasons have been observed. 相似文献
497.
S. V. Raman Rao B. Padmavathi K. Sathyavelu Reddy K. Indira 《Chemistry and Ecology》2013,29(4):207-212
Exposure of a freshwater teleost, Sarotherodon mossambicus, to a sublethal concentration (26 ppm) of carbon tetrachloride for periods up to 30 days led to significant changes in the soluble protein fractions (albumin and globulins) and free amino acid content. the decrease in total protein content was greater in liver than in muscle. the protein loss was expected due to the impairement of protein synthetic activity during stress conditions. 相似文献
498.
ZOE JEWELL 《Conservation biology》2013,27(3):501-508
Monitoring free‐ranging animals in their natural habitat is a keystone of ecosystem conservation and increasingly important in the context of current rates of loss of biological diversity. Data collected from individuals of endangered species inform conservation policies. Conservation professionals assume that these data are reliable—that the animals from whom data are collected are representative of the species in their physiology, ecology, and behavior and of the populations from which they are drawn. In the last few decades, there has been an enthusiastic adoption of invasive techniques for gathering ecological and conservation data. Although these can provide impressive quantities of data, and apparent insights into animal ranges and distributions, there is increasing evidence that these techniques can result in animal welfare problems, through the wide‐ranging physiological effects of acute and chronic stress and through direct or indirect injuries or compromised movement. Much less commonly, however, do conservation scientists consider the issue of how these effects may alter the behavior of individuals to the extent that the data they collect could be unreliable. The emerging literature on the immediate and longer‐term effects of capture and handling indicate it can no longer be assumed that a wild animal's survival of the process implies the safety of the procedure, that the procedure is ethical, or the scientific validity of the resulting data. I argue that conservation professionals should routinely assess study populations for negative effects of their monitoring techniques and adopt noninvasive approaches for best outcomes not only for the animals, but also for conservation science. Efecto de la Técnica de Monitoreo en la Calidad de la Ciencia de la Conservación 相似文献
499.
Secondary copper production is one of the key polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) emission sources in China, but research and data on this issue are rare. In 2004, when the Stockholm Convention entered into force in China, PCDD/Fs emissions from secondary copper production contributed to 32.2% of the total release. In this paper, PCDD/Fs emission dynamics from secondary copper industry were discussed and cumulative risks were characterized. From 2004 to 2009, industrial policies played an indirect role in PCDD/Fs reduction, but its effects are still limited. The Yangtze River Delta, Pearl River Delta and central regions were among the top three of dioxin emissions from secondary copper production in China. Shanghai, Shandong, Zhejiang, and Jiangxi had comparatively higher accumulated risk and were recommended as the priority regions for promoting PCDD/Fs emission control in China. From 2009 to 2015, the PCDD/Fs emission dynamics in the secondary copper industry were presented through simulation. PCDD/Fs emission equations were established, resulting in the recommendation of control technology conversion rate at 30% for small scale smelters and 51%–57% for large and medium-sized enterprises in 2015. In conclusion, both indirect policy and direct control technology retrofitting should be integrated for more effective PCDD/Fs emission reduction in secondary copper industry. 相似文献
500.
中国汞污染的来源、成因及控制技术路径分析 总被引:8,自引:0,他引:8
汞是一种能长期存在于环境且具有全球迁移性的污染物.汞污染防治是一个复杂的系统工程,涉及多部门、多领域、多行业,国家需要在政策、管理和技术等方面采取综合的战略措施推进汞污染防治.本文基于汞污染的环境和社会影响,分析了中国汞污染的来源、成因并评估了中国汞管理体系,结合中国参加全球汞公约谈判的特定背景,识别出汞污染防控的优先行业,包括汞的无意排放优先控制行业:燃煤、有色金属冶炼、汞矿开采和含汞废物处理;汞的有意使用优先控制行业:电石法聚氯乙烯生产,医疗产品、荧光灯和电池生产.本文也进一步提出了汞污染控制技术路径,包括构建汞风险管理和识别平台、完善汞管理体系、加强环境技术研发、推进绿色转型、保护环境和公众健康等. 相似文献