全文获取类型
收费全文 | 459篇 |
免费 | 47篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 93篇 |
废物处理 | 20篇 |
环保管理 | 49篇 |
综合类 | 150篇 |
基础理论 | 35篇 |
污染及防治 | 14篇 |
评价与监测 | 42篇 |
社会与环境 | 18篇 |
灾害及防治 | 87篇 |
出版年
2025年 | 4篇 |
2024年 | 10篇 |
2023年 | 11篇 |
2022年 | 16篇 |
2021年 | 15篇 |
2020年 | 27篇 |
2019年 | 23篇 |
2018年 | 28篇 |
2017年 | 15篇 |
2016年 | 18篇 |
2015年 | 27篇 |
2014年 | 34篇 |
2013年 | 24篇 |
2012年 | 26篇 |
2011年 | 20篇 |
2010年 | 17篇 |
2009年 | 12篇 |
2008年 | 8篇 |
2007年 | 32篇 |
2006年 | 17篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 11篇 |
2002年 | 16篇 |
2001年 | 6篇 |
2000年 | 11篇 |
1999年 | 10篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 11篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有508条查询结果,搜索用时 15 毫秒
81.
为研究城市地铁沿线老旧房屋普遍存在结构安全问题,基于机器学习模型,选取房屋年份、楼层、面积等11个属性构建预警指标体系,采用SMOTE过采样、独热编码等方法解决样本离散化、不均衡的问题;利用KNN、Bayes、Logistic、SVM 4种机器学习模型对房屋结构安全数据学习并测试,综合应用Accuracy、F1、AP、... 相似文献
82.
83.
84.
85.
86.
Environmental supply chain is a desirable alternative to traditional supply chain due to new and stricter environmental regulations by local governments and increasing consumer awareness towards environmental issues. The two most common types of environmental supply chains are reverse supply chains and closed-loop supply chains. In reverse or closed-loop supply chains, collected used products are subjected to one of four recovery options, viz., reuse, recycling, remanufacturing or disposal. Regardless of the chosen recovery option, all products are disassembled up to some level. However, there is a high level of uncertainty associated with the disassembly yield due to non-functional and/or missing components. Sensor embedded products (SEPs) is a viable approach to cope with this uncertainty since they involve sensors which can detect non-functional and/or missing components prior to disassembly. This study presents a quantitative assessment of the impact of SEPs on the various performance measures of a kanban-controlled disassembly line. First, separate design of experiments studies based on Orthogonal Arrays are carried out for conventional products and SEPs. Then, the results of paired t-tests comparing the two cases based on different performance measures are presented. 相似文献
87.
Processing and Characterization of Short-Fiber Reinforced Jute/Poly Butylene Succinate Biodegradable Composites: The Effect of Weld-Line 总被引:2,自引:0,他引:2
U.?S.?IshiakuEmail author O.?A.?Khondker S.?Baba A.?Nakai H.?Hamada 《Journal of Polymers and the Environment》2005,13(2):151-157
Fabrication of complex injection molded parts often involves the use of multiple gates. In such situations, polymer melts from different gates meld to form the molded part (weld line). This paper reports on the fabrication and characterization of the mechanical and morphological properties of short fiber reinforced jute/poly butylene succinate (PBS) biodegradable composites. The effect of a dual gated mold in the fabrication of welded specimens was a key focus of the investigation. It was observed that incorporation of jute fiber (10 wt%) conferred drastic changes on the stress–strain properties of the matrix as the elongation at break (EB), dropped from 160% in the matrix to just 10% in the composite. The tensile strength of the composite was lower than that of the matrix. However, it is noteworthy that the tensile modulus of the composite increased. Bending test also revealed that both bending strength and modulus increased with the incorporation of jute. Morphological studies of the tensile fracture surface using SEM revealed two types of failure mode. Ductile failure was indicated by plastic deformation at the initiation of fracture followed by brittle failure. The good interfacial bonding indicated between jute and PBS was attributed to positive interaction between the two polar polymers. A comparison of the non-weld and weld-line samples revealed that the weld-line composites have better mechanical integrity than the corresponding polymer matrix with weld line. The results also revealed that elongation at break and toughness are most sensitive to the presence of the weld-line whereas flexural properties are least sensitive. 相似文献
88.
89.
90.
近年来,毛细管电泳以其速度快、效率高的分离分析技术受到越来越多领域的青睐,样品在线富集的方法有效的提高毛细管电泳由于进样体积小而造成的检测灵敏度难以提高的问题。文章简单介绍了毛细管电泳在线富集的原理,对其方法与应用进行了总结与概述。 相似文献