全文获取类型
收费全文 | 39649篇 |
免费 | 1432篇 |
国内免费 | 8144篇 |
专业分类
安全科学 | 2335篇 |
废物处理 | 2079篇 |
环保管理 | 4278篇 |
综合类 | 15879篇 |
基础理论 | 8042篇 |
环境理论 | 6篇 |
污染及防治 | 11739篇 |
评价与监测 | 2037篇 |
社会与环境 | 1712篇 |
灾害及防治 | 1118篇 |
出版年
2023年 | 410篇 |
2022年 | 1188篇 |
2021年 | 1092篇 |
2020年 | 879篇 |
2019年 | 807篇 |
2018年 | 1086篇 |
2017年 | 1251篇 |
2016年 | 1311篇 |
2015年 | 1521篇 |
2014年 | 2219篇 |
2013年 | 3648篇 |
2012年 | 2478篇 |
2011年 | 2687篇 |
2010年 | 2231篇 |
2009年 | 2171篇 |
2008年 | 2501篇 |
2007年 | 2148篇 |
2006年 | 2062篇 |
2005年 | 1461篇 |
2004年 | 1295篇 |
2003年 | 1354篇 |
2002年 | 1231篇 |
2001年 | 1276篇 |
2000年 | 1149篇 |
1999年 | 867篇 |
1998年 | 771篇 |
1997年 | 761篇 |
1996年 | 706篇 |
1995年 | 615篇 |
1994年 | 536篇 |
1993年 | 466篇 |
1992年 | 471篇 |
1991年 | 365篇 |
1990年 | 370篇 |
1989年 | 285篇 |
1988年 | 246篇 |
1987年 | 202篇 |
1986年 | 189篇 |
1985年 | 186篇 |
1984年 | 208篇 |
1983年 | 195篇 |
1982年 | 207篇 |
1981年 | 191篇 |
1980年 | 137篇 |
1979年 | 154篇 |
1978年 | 131篇 |
1977年 | 117篇 |
1975年 | 119篇 |
1974年 | 117篇 |
1972年 | 134篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
Journal of Material Cycles and Waste Management - The iron ore tailing (IOT) is an industrial waste, in which large accumulations represent a serious environmental threat. To reduce the... 相似文献
12.
Xi-Gao Shao Bi-Feng Liao Bang-Yi Li 《International Journal of Sustainable Engineering》2019,12(1):30-37
The rapid development of technology has made it easier to distribute products directly, and many enterprises excel at executing a multi-channel strategy to distribute products. The introduction of direct channel adds a new competition dimension to the enterprises. This paper considers three market channel structures: R-Channel, D-Channel and H-Channel. In R-Channel, both new products and remanufactured products are sold through a retailer. In D-Channel, new products are sold through retailers and remanufactured products are sold directly to consumers. In H-Channel, new products are sold through retailers, while remanufactured products through dual channel. Using the game theory, we obtain and analyse the equilibrium prices, market demands and the profits gain under these three settings. At the same time, the influence of consumers’ willingness to pay on the environment performance is researched. Our results show that the manufacturer prefers H-Channel. By introducing the direct channel the manufacturer is always economically better off, but it is not for the retailer. The numerical simulation also confirms the theoretical analysis and shows that H-Channel has advantages of economic benefit and environmental performance. It is feasible for practical application. 相似文献
13.
Li Haoxin Huang Yuyan Yang Xiaojie Jiang Zhengwu Yang Zhenghong 《Journal of Material Cycles and Waste Management》2018,20(3):1701-1709
Journal of Material Cycles and Waste Management - This work aims to develop another approach to the management of magnesium slag (MS) via the production of Portland cement clinker. Thus, 0, 10, 20,... 相似文献
14.
Shu-Yii Wu Yong-Fang Liu Ya-Chieh Li Chun-Min Liu 《International Journal of Green Energy》2015,12(10):1025-1030
The CO2 absorption capacities of potassium glycinate, potassium sarcosinate (choline, proline), mono-ethanolamine (MEA), and tri-ethanolamine were evaluated to find the optimal absorbent for separating CO2 from gaseous products by a CO2 purification process. The absorption loading, desorption efficiency, cost, and environmental tolerance were assessed to select the optimal absorbent. MEA was found to be the optimum absorbent for separating the CO2 and H2 mixture in gaseous product. The maximum absorption loading rate was 0.77 mol CO2 per mol MEA at temperature of 20°C and absorbent concentration of 2.5 mol/L, whereas desorption efficiency was 90% by heating for 3 h at 130°C. MEA was found to be an optimal absorbent for the purification process of CO2 during gaseous production. 相似文献
15.
Comparison of different sequential extraction procedures for mercury fractionation in polluted soils
Dong Haochen Feng Liu Qin Yu Luo Muxinjian 《Environmental science and pollution research international》2019,26(10):9955-9965
Environmental Science and Pollution Research - Three sequential extraction procedures (SEPs), modified Tessier, modified BCR, and CIEMAT, were compared for mercury fractionation in polluted soils.... 相似文献
16.
建立健全生态文明制度体系是推进我国生态文明建设的重点。党的十八届三中全会通过的《中共中央关于全面深化改革若干重大问题的决定》指出,生态文明制度体系应当包括决策制度、评价制度、管理制度与考核制度等内容。立足社会主义制度建设的中国特色,针对我国生态文明建设的具体需求,本文将生态文明制度体系解构为四大板块:绿色高效决策制度、生态有价评估制度、生态环境监管制度与生态优先考核制度,并进一步明确了各项制度构建工作的具体内容。生态文明制度体系的构建和不断完善,将为全面建成人与自然和谐的美丽中国提供系统保障。 相似文献
17.
18.
Ling R. Zeng Li H. Shi Xin G. Meng J. Xu Gui F. Jia T. Gui 《Journal of environmental science and health. Part. B》2019,54(4):317-325
This study evaluated the hydrolysis and photolysis kinetics of pyraclostrobin in an aqueous solution using ultra-high-performance liquid chromatography–photodiode array detection and identified the resulting metabolites of pyraclostrobin by hydrolysis and photolysis in paddy water using high-resolution mass spectrometry coupled with liquid chromatography. The effect of solution pH, metal ions and surfactants on the hydrolysis of pyraclostrobin was explored. The hydrolysis half-lives of pyraclostrobin were 23.1–115.5?days and were stable in buffer solution at pH 5.0. The degradation rate of pyraclostrobin in an aqueous solution under sunlight was slower than that under UV photolysis reaction. The half-lives of pyraclostrobin in a buffer solution at pH 5.0, 7.0, 9.0 and in paddy water were less than 12?h under the two light irradiation types. The metabolites of the two processes were identified and compared to further understand the mechanisms underlying hydrolysis and photolysis of pyraclostrobin in natural water. The extracted ions obtained from paddy water were automatically annotated by Compound Discoverer software with manual confirmation of their fragments. Two metabolites were detected and identified in the pyraclostrobin hydrolysis, whereas three metabolites were detected and identified in the photolysis in paddy water. 相似文献
19.
Wildlife provides food, medicine, clothing, and other necessities for humans, but overexploitation can disrupt the sustainability of wildlife resources and severely threaten global biodiversity. Understanding the characteristics of consumer behavior is helpful for wildlife managers and policy makers, but the traditional survey methods are laborious and time-consuming. In contrast, culturomics may more efficiently identify the features of wildlife consumption. As a case study of the culturomics approach, we examined tiger bone wine consumption in China based on social media and Baidu search engine data. Tiger bone wine is one of the most purchased tiger products; its consumption is closely related to tiger poaching, which greatly threatens wild tiger survival. We searched a popular social media website for the term “tiger bone wine” and focused on posts that were originally created from 1 January 2012 to 31 December 2018. We filtered and classified posts related to the purchase, sale, or consumption of tiger bone wine and extracted information on providers, consumption motivations, year of production, and place of origin of the tiger bone wines based on the texts and photos of these posts. We found 756 posts related to tiger bone wine consumption, 113 of which mentioned providers of tiger bone wine, including friends (53%), elder relatives (37%), peer relatives (7%), and others (3%). Out of the 756 posts, 266 indicated the motivations of tiger bone wine consumption. Tiger bone wines were consumed as a tonic (34%), medicine (23%), game product (30%), and a symbol of wealth (28%). Some posts indicated ≥2 consumption motivations. These findings were consistent with the search queries from Baidu index. Such information could help develop targeted strategies for tiger conservation. The culturomics approach illustrated by our study is a rapid and cost-efficient way to characterize wildlife consumption. 相似文献
20.
采用大肠杆菌吸附-化学还原法,以大肠杆菌(ECCs)为模板、十六烷基三甲基溴化铵为保护剂、抗坏血酸为还原剂,由废含金催化剂制备金纳米线(AuNWs)。采用XRD,SEM,TEM等技术对AuNWs进行表征。研究了AuNWs对罗丹明6G(R6G)和4-巯基苯甲酸(4-MBA)的拉曼散射信号的增强效果。实验结果表明:在制备过程中加入微生物ECCs,可使金回收率提高约20百分点;当溶液pH小于4时,反应2 h后,有大量呈线状的AuNWs聚集沉降,金回收率可达99%1以上。表征结果显示,AuNWs呈多晶结构,晶格间距为0.23 nm。表面增强拉曼散射分析表明,AuNWs对R6G和4-MBA具有良好的拉曼光谱增强性能。 相似文献