全文获取类型
收费全文 | 17066篇 |
免费 | 1071篇 |
国内免费 | 2432篇 |
专业分类
安全科学 | 2633篇 |
废物处理 | 179篇 |
环保管理 | 2692篇 |
综合类 | 8476篇 |
基础理论 | 1859篇 |
环境理论 | 14篇 |
污染及防治 | 1272篇 |
评价与监测 | 881篇 |
社会与环境 | 1496篇 |
灾害及防治 | 1067篇 |
出版年
2024年 | 49篇 |
2023年 | 241篇 |
2022年 | 399篇 |
2021年 | 506篇 |
2020年 | 476篇 |
2019年 | 433篇 |
2018年 | 374篇 |
2017年 | 537篇 |
2016年 | 662篇 |
2015年 | 661篇 |
2014年 | 690篇 |
2013年 | 900篇 |
2012年 | 1087篇 |
2011年 | 1249篇 |
2010年 | 900篇 |
2009年 | 918篇 |
2008年 | 754篇 |
2007年 | 1133篇 |
2006年 | 1150篇 |
2005年 | 933篇 |
2004年 | 781篇 |
2003年 | 890篇 |
2002年 | 704篇 |
2001年 | 595篇 |
2000年 | 548篇 |
1999年 | 540篇 |
1998年 | 409篇 |
1997年 | 319篇 |
1996年 | 273篇 |
1995年 | 248篇 |
1994年 | 246篇 |
1993年 | 212篇 |
1992年 | 160篇 |
1991年 | 132篇 |
1990年 | 82篇 |
1989年 | 53篇 |
1988年 | 51篇 |
1987年 | 26篇 |
1986年 | 25篇 |
1985年 | 32篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 17篇 |
1977年 | 13篇 |
1973年 | 14篇 |
1972年 | 12篇 |
1971年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Carbon footprint of food - approaches from national input-output statistics and a LCA of a food portion 总被引:1,自引:0,他引:1
Yrjö Virtanen Sirpa KurppaMerja Saarinen Juha-Matti KatajajuuriKirsi Usva Ilmo MäenpääJohanna Mäkelä Juha GrönroosAri Nissinen 《Journal of Cleaner Production》2011,19(16):1849-1856
The aim of the study, on which this paper is based, was to provide guidance to consumers to make environmentally responsible choices in their food consumption, to assist food supply chain stakeholders to identify the key areas for environmental improvements, and to provide policy makers with a tool for monitoring the potential impacts on climate change resulting from developments within the food sector. At the macro level, the EIO-LCA model was developed specifically for the Finnish food chain; at the micro level, LCAs were performed on 30 lunch portions. The contribution of the Finnish food chain to climate change was 14%, which comprised 40% CO2 emissions, 25% CH4 emissions, and 34% N2O emissions. The share of impacts from domestic agricultural processes was the highest, at 69%. The impact of a single lunch portion ranged between 0.65 and 3.80 kg of equivalent CO2. According to the EIO-LCA model, the average impact was 7.7 kg CO2 eq/person daily. The consumer phase accounted for between 8 and 47% of the climate change impacts for homemade portions. In ready-to-eat portions industry and retail phases were emphasized, representing 25-38% of climate change impacts. We present an approach to steer the Finnish food sector onto an environmentally sustainable path; practical tools for consumers and farmers will especially need to be developed further. 相似文献
992.
993.
化石燃料的大量使用所排放的温室气体使得全球气候日益变暖,低碳经济的提出成为了目前全球应对气候变暖的主要策略,而发展中国家在进行低碳技术引进时常常面临来自发达国家的知识产权贸易壁垒。本文从"公地悲剧"角度解析气候变暖的经济学根源,从"反公地悲剧"角度揭示低碳技术转让过程中发达国家以知识产权为借口制造技术壁垒的经济学缘由。 相似文献
994.
上市公司是一种特殊的企业形式,法律要求其在设立和生产经营过程中进行信息披露,来保护利益相关者的权益。涉及到环境信息的披露,上市公司受到环境法和证券法的双重监管,由于监管的理念和宗旨存在差异,导致监管的主体、内容和方式也存在着很大的不同。 相似文献
995.
996.
997.
介绍了国内目前正在使用或即将使用的燃煤烟气脱硫技术的工艺特点、操作参数和适用范围。这些技术包括湿式石灰石(石灰)-石膏法、炉内喷钙后部烟气增湿脱硫法、海水洗涤法、除尘脱硫一体化技术等。 相似文献
998.
Fractionation of Cu, Pb and Zn in certified reference soils SRM 2710 and SRM 2711 using the optimized BCR sequential extraction procedure 总被引:4,自引:0,他引:4
Sequential extraction of metals from solid media is a common analytical tool used in environmental and exploration geochemistry. A number of procedures exist, but without harmonization and standardization, meaningful comparisons are tenuous without baseline data. A newly developed, standardized sequential extraction procedure (optimized BCR) was applied to two contaminated certified reference soils from Montana, US (SRM 2710 and SRM 2711) for Cu, Pb and Zn. Four operationally defined fractions were isolated, acid extractable, reducible, oxidizable, and residual (by aqua regia). Fraction-specific concentrations, percentages and recoveries for Cu, Pb and Zn were used to explore differences between the optimized BCR procedure and three other sequential extraction schemes with published data for SRM 2710 and 2711 (i.e. Tessier scheme, Geological Survey of Canada scheme and the original BCR scheme). Results indicate significant differences between the four schemes, even for schemes that are closely associated (i.e. the original and optimized BCR schemes). Order-of-magnitude fraction-specific concentration differences were observed, especially for Pb in the reducible fraction. Differences between schemes are worrisome because trends varied between metals, between fractions and between reference soils. These data reinforce the need for increased adoption of standardized sequential extraction procedures and further examination of different solid media. 相似文献
999.
Molecular diagnostic tests are becoming a routine analysis in many laboratories. These modern analyses are widely used in clinical medicine, forensic, genetic and prenatal diagnosis and also in preimplantation genetic diagnosis. The accuracy of analysis is highly dependent on the success achieved in minimising genotyping errors. The pitfalls in molecular diagnostic tests can be due to a simple technique such as the polymerase chain reaction (PCR) used universally. This technique is routinely used for its apparent accuracy, but it is also a well-known source of errors. We report an error introduced during PCR reaction that leads to a wrong sequence result and consequently to a ‘false’ molecular result in a next prenatal diagnosis in a family with severe factor VII (FVII) deficiency. This error was verified using an unsuitable primer design in a rich repetitive sequence of the FVII gene that leads to a false annealing and then to a wrong molecular diagnosis. It is essential to link closely molecular data with clinical and phenotype analysis in order to avoid false-negative or false-positive results, which is of great importance to diagnosis and molecular prevention. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
1000.
A new approach applying fuzzy mathematic theorems, including the Primary Matrix Element Theorem and the Fisher Classification Method, was established to solve the optimization problem of atmospheric environmental sampling sites. According to its basis, an application in the optimization of sampling sites in the atmospheric environmental monitoring was discussed. The method was proven to be suitable and effective. The results were admitted and applied by the Environmental Protection Bureau (EPB) of many cities of China. A set of computer software of this approach was also comuletelv comniled and used. 相似文献