全文获取类型
收费全文 | 953篇 |
免费 | 46篇 |
国内免费 | 363篇 |
专业分类
安全科学 | 65篇 |
废物处理 | 55篇 |
环保管理 | 87篇 |
综合类 | 509篇 |
基础理论 | 197篇 |
污染及防治 | 303篇 |
评价与监测 | 33篇 |
社会与环境 | 36篇 |
灾害及防治 | 77篇 |
出版年
2023年 | 15篇 |
2022年 | 51篇 |
2021年 | 41篇 |
2020年 | 30篇 |
2019年 | 29篇 |
2018年 | 44篇 |
2017年 | 46篇 |
2016年 | 45篇 |
2015年 | 70篇 |
2014年 | 82篇 |
2013年 | 98篇 |
2012年 | 96篇 |
2011年 | 98篇 |
2010年 | 69篇 |
2009年 | 59篇 |
2008年 | 66篇 |
2007年 | 59篇 |
2006年 | 38篇 |
2005年 | 37篇 |
2004年 | 19篇 |
2003年 | 25篇 |
2002年 | 26篇 |
2001年 | 26篇 |
2000年 | 24篇 |
1999年 | 26篇 |
1998年 | 25篇 |
1997年 | 20篇 |
1996年 | 21篇 |
1995年 | 21篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有1362条查询结果,搜索用时 31 毫秒
101.
102.
The presence of Bacillus thuringiensis (Bt) protein in earthworms Eisenia fetida has no deleterious effects on their growth and reproduction 总被引:1,自引:0,他引:1
Earthworms Eisenia fetida, bred in substances with stover of two genetically-engineered Bacillus thuringiensis (Bt) corns (5422Bt1 (Event Bt11) and 5422CBCL (MON810)) expressing Cry1Ab and their near-isogenic non-Bt corn (5422), were used to investigate the non-target effects of Bt corn on soil-dwelling organisms. Cry1Ab concentrations in substances, casts and guts of E. fetida were also investigated by Enzyme-linked immunosorbent assay (ELISA). More than 90% individuals of E. fetida survived over a period of 30 d, irrespective of whether they received Bt corn or non-Bt corn. Compared to 5422 treatments, significantly higher relative growth rate and more number of new offspring and cocoons of E. fetida were found in 5422Bt1 and 5422CBCL treatments. These results were unlikely to be directly caused by Cry1Ab released from Bt corns but rather by differences in other factors of plants such as plant components (soluble sugar, total organic carbon, total protein and available phosphorus of Bt corns were more than 5422). ELISA results indicated immunoreactive Cry1Ab was detectable in substances, and the casts, guts of E. fetida from Bt corns treatments, of which the highest levels were detected in substances under the corresponding experimental conditions. With the increase of treated time, a strong decline was observed in Cry1Ab from substances and casts of E. fetida, whereas Cry1Ab in guts of E. fetida from 5422Bt1 treatments gradually increased and that from 5422CBCL treatments increased between 14 and 30 d. Therefore, the presence of Cry1Ab in E. fetida had no deleterious effects on their growth and reproduction. 相似文献
103.
104.
Du YB Lee CT Christina D Belfer ML Betancourt TS O'Rourke EJ Palfrey JS 《Disasters》2012,36(3):495-513
The tsunami that struck South-east Asia on 26 December 2004 left more than 500,000 people in Aceh, Indonesia, homeless and displaced to temporary barracks and other communities. This study examines the associations between prolonged habitation in barracks and the nature of fears reported by school-age children and adolescents. In mid-2007, 30 months after the tsunami, the authors interviewed 155 child and parent dyads. Logistic regression analysis was used to compare the fears reported by children and adolescents living in barracks with those reported by their peers who were living in villages. After adjusting for demographic factors and tsunami exposure, the data reveals that children and adolescents living in barracks were three times more likely than those living in villages to report tsunami-related fears. The study demonstrates that continued residence in barracks 30 months after the tsunami is associated with higher rates of reporting tsunami-related fears, suggesting that barracks habitation has had a significant impact on the psychological experience of children and adolescents since the tsunami. 相似文献
105.
Although marine and terrestrial emissions simultaneously affect the formation of atmospheric fine particles in coastal areas, knowledge on the optical properties and sources of water-soluble matter in these areas is still scarce. In this work, taking Qingdao, China as a typical coastal location, the chemical composition of PM2.5 during winter 2019 was analyzed.Excitation-emission matrix fluorescence spectroscopy was combined with parallel factor analysis model to explain the component... 相似文献
106.
107.
Jun Zhang Ding Gao Tong-Bin Chen Guo-Di Zheng Jun Chen Chuang Ma Song-Lin Guo Wei Du 《Waste management (New York, N.Y.)》2010,30(10):1931-1938
To simulate the substrate degradation kinetics of the composting process, this paper develops a mathematical model with a first-order reaction assumption and heat/mass balance equations. A pilot-scale composting test with a mixture of sewage sludge and wheat straw was conducted in an insulated reactor. The BVS (biodegradable volatile solids) degradation process, matrix mass, MC (moisture content), DM (dry matter) and VS (volatile solid) were simulated numerically by the model and experimental data. The numerical simulation offered a method for simulating k (the first-order rate constant) and estimating k20 (the first-order rate constant at 20 °C). After comparison with experimental values, the relative error of the simulation value of the mass of the compost at maturity was 0.22%, MC 2.9%, DM 4.9% and VS 5.2%, which mean that the simulation is a good fit. The k of sewage sludge was simulated, and k20, k20s (first-order rate coefficient of slow fraction of BVS at 20 °C) of the sewage sludge were estimated as 0.082 and 0.015 d?1, respectively. 相似文献
108.
摆脱传统思维方式的束缚,采用科学的、系统的、程序化的方法制定我国县级经济和社会发展战略,是我国现代化建设提出的一项艰巨任务。本文旨在通过介绍“绵竹县经济社会发展总体规划(系统工程应用)研究”的核心部分——绵竹县社会经济系统动态仿真模型设计与发展战略的仿真实验择优,阐述系统工程的原理和运用数学模型方法对县级社会经济系统进行总体设计、预演和优化的一点体会。 相似文献
109.
110.
陕西关中地区城市灾害评价 总被引:8,自引:2,他引:8
本文在详细分析关中地区六个大中城市的主要自然灾害和城市地质灾害的基础上,分别评价了各种灾害造成的经济损失,各个城市的灾害危险性、易损性和抗灾能力,并结合防灾对策对城市进行了综合分类。 相似文献