全文获取类型
收费全文 | 3494篇 |
免费 | 296篇 |
国内免费 | 1332篇 |
专业分类
安全科学 | 161篇 |
废物处理 | 496篇 |
环保管理 | 395篇 |
综合类 | 2501篇 |
基础理论 | 667篇 |
污染及防治 | 615篇 |
评价与监测 | 241篇 |
社会与环境 | 35篇 |
灾害及防治 | 11篇 |
出版年
2024年 | 5篇 |
2023年 | 40篇 |
2022年 | 70篇 |
2021年 | 96篇 |
2020年 | 112篇 |
2019年 | 94篇 |
2018年 | 103篇 |
2017年 | 127篇 |
2016年 | 159篇 |
2015年 | 192篇 |
2014年 | 284篇 |
2013年 | 360篇 |
2012年 | 282篇 |
2011年 | 301篇 |
2010年 | 211篇 |
2009年 | 235篇 |
2008年 | 202篇 |
2007年 | 282篇 |
2006年 | 261篇 |
2005年 | 189篇 |
2004年 | 168篇 |
2003年 | 170篇 |
2002年 | 162篇 |
2001年 | 127篇 |
2000年 | 126篇 |
1999年 | 123篇 |
1998年 | 127篇 |
1997年 | 95篇 |
1996年 | 87篇 |
1995年 | 63篇 |
1994年 | 67篇 |
1993年 | 36篇 |
1992年 | 42篇 |
1991年 | 40篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1973年 | 3篇 |
排序方式: 共有5122条查询结果,搜索用时 15 毫秒
131.
132.
采用絮凝法对味精发酵生产过程中发酵液中的菌体进行研究,得到无机凝聚剂与高分子絮凝剂复合配比使用是发酵液去除菌体的有效办法。对复合用药除菌后的谷氨酸发酵液和原谷氨酸发酵液进行谷氨酸回收的比较,谷氨酸的回收率提高了8.8%。 相似文献
133.
134.
Research on biodegradable materials has been stimulated due to concern regarding the persistence of plastic wastes. Blending starch with poly(lactic acid) (PLA) is one of the most promising efforts because starch is an abundant and cheap biopolymer and PLA is biodegradable with good mechanical properties. Poly(vinyl alcohol) (PVOH) contains unhydrolytic residual groups of poly(vinyl acetate) and also has good compatibility with starch. It was added to a starch and PLA blend (50:50, w/w) to enhance compatibility and improve mechanical properties. PVOH (MW 6,000) at 10%, 20%, 30%, 40%, 50% (by weight) based on the total weight of starch and PLA, and 30% PVOH at various molecular weights (MW 6,000, 25,000, 78,000, and 125,000 dalton) were added to starch/PLA blends. PVOH interacted with starch. At proportions greater than 30%, PVOH form a continuous phase with starch. Tensile strength of the starch/PLA blends increased as PVOH concentration increased up to 40% and decreased as PVOH molecular weight increased. The increasing molecular weight of PVOH slightly affected water absorption, but increasing PVOH concentration to 40% or 50% increased water absorption. Effects of moisture content on the starch/PLA/PVOH blend also were explored. The blend containing gelatinized starch had higher tensile strength. However, gelatinized starch also resulted in increased water absorption. 相似文献
135.
孟玲 《中国环境管理干部学院学报》2003,13(2):17-19
本文分析了玻璃生产企业废水的来源,并从耀华玻璃集团实施的废水治理项目的实际出发,阐述了废水经过治理后综合利用的途径,实现废水的零排放,减少环境污染,节约水资源。 相似文献
136.
城市垃圾甲烷气体排放及减排对策 总被引:6,自引:0,他引:6
本文讲述了城市垃圾的现状以及影响垃圾甲烷排放的各种因素,并根据IPCCGuidelines(1995)提供的方法对1990~2010年江浙沪地区城市垃圾甲烷排放量的变化趋势进行了预测统计计算,1990年江浙沪地区城市垃圾甲烷排放量为7123万吨,2010年预测的甲烷排放量为26676万吨,本文就垃圾中甲烷的排放提出了切实可行的减排方案。 相似文献
137.
Geraldo Ferrer 《Resources, Conservation and Recycling》1997,19(4):221-255
The world market for tires is described to identify the current material flow from raw materials to tires and the used tire disposal problem. Then, I describe the value-adding operations in the tire production process and in the tire retreading process. Once retreading is identified as the only recovery alternative that maximizes tire utilization, I explain why heat generation is the only recovery alternative, when retreading is not technically feasible. The economic values of heat generation in electric plants and in cement kilns are discussed. The paper culminates with the case of retreading, the tire remanufacturing process and the recommendation of a simple decision rule for selecting the number of times a tire should be retreaded to maximize its utilization. 相似文献
138.
废水中甲酸萃取回收的研究 总被引:9,自引:1,他引:9
以ZYM混合溶剂为萃取剂,以含4.5%的甲酸的废水进行萃取试验,结果表明,ZYM具有良好的热稳定性和再生性,对废水中的甲酸有较高的萃取率。采用本萃取技术,不但具有显著的环境效益,而且还可回收甲酸,获得较好的经济效益。 相似文献
139.
140.
Thermal and mechanical properties of poly(lactic Acid) and poly(ethylene/butylene Succinate) blends 总被引:2,自引:0,他引:2
In this study, blends of poly (lactic acid) (PLA) with poly(ethylene/butylene succinate) (Bionolle) have been investigated
for their thermal and mechanical properties as a function of the concentration of Bionolle. Differential scanning calorimetry
(DSC), dynamic mechanical analysis (DMA), and tensile tests were used to characterize the blends. From the results of the
DMA and DSC, it was found that this blend system was not miscible within the compositions studied. DSC results showed that
adding Bionolle aids in crystallization of PLA. It was observed that increasing the Bionolle concentration led to a slight
increase in the strain-at-break of the blends but a decrease in the Young’s modulus and ultimate tensile strength. Biaxially
oriented films showed an increase in tensile strength, modulus, and strain-at-break. 相似文献