全文获取类型
收费全文 | 1717篇 |
免费 | 279篇 |
国内免费 | 675篇 |
专业分类
安全科学 | 277篇 |
废物处理 | 56篇 |
环保管理 | 150篇 |
综合类 | 1329篇 |
基础理论 | 244篇 |
环境理论 | 1篇 |
污染及防治 | 304篇 |
评价与监测 | 120篇 |
社会与环境 | 106篇 |
灾害及防治 | 84篇 |
出版年
2024年 | 17篇 |
2023年 | 66篇 |
2022年 | 151篇 |
2021年 | 126篇 |
2020年 | 155篇 |
2019年 | 102篇 |
2018年 | 105篇 |
2017年 | 109篇 |
2016年 | 123篇 |
2015年 | 138篇 |
2014年 | 136篇 |
2013年 | 180篇 |
2012年 | 210篇 |
2011年 | 178篇 |
2010年 | 138篇 |
2009年 | 150篇 |
2008年 | 112篇 |
2007年 | 96篇 |
2006年 | 95篇 |
2005年 | 57篇 |
2004年 | 55篇 |
2003年 | 36篇 |
2002年 | 34篇 |
2001年 | 19篇 |
2000年 | 20篇 |
1999年 | 13篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 11篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1983年 | 2篇 |
排序方式: 共有2671条查询结果,搜索用时 62 毫秒
821.
822.
823.
Polyaluminum chloride was synthesized with a membrane reactor, and the process characteristics, membrane fouling and cleaning were investigated. 相似文献
824.
Moisture distributions in municipal sewage sludge, printing and dyeing sludge and paper mill sludge were experimentally studied
based on four di erent methods, i.e., drying test, thermogravimetric-di erential thermal analysis (TG-DTA) test, thermogravimetricdi
erential scanning calorimetry (TG-DSC) test and water activity test. The results indicated that the moistures in the mechanically
dewatered sludges were interstitial water, surface water and bound water. The interstitial water accounted for more than 50% wet basis
(wb) of the total moisture content. The bond strength of sludge moisture increased with decreasing moisture content, especially when
the moisture content was lower than 50% wb. Furthermore, the comparison among the four di erent testing methods was presented.
The drying test was advantaged by its ability to quantify free water, interstitial water, surface water and bound water; while TG-DSC
test, TG-DTA test and water activity test were capable of determining the bond strength of moisture in sludge. It was found that the
results from TG-DSC and TG-DTA test are more persuasive than water activity test. 相似文献
825.
Glucose oxidase (GOD) is widely used in the glucose biosensor industry. The amperometric biosensors based on directly electron transfer (DET) between an electrode and immobilized GOD are especially promising. In this article, GOD was immobilized with a DNA/chitosan bio-material film on GC electrode, and the DET of GOD on DNA/chitosan was studied. The cyclic voltammetric results indicated that the GOD immobilized in the DNA/chitosan film underwent DET reaction, and the cyclic voltammogram displayed a pair of well-defined redox peaks with a formal potential of ?0.45 V (vs. Ag/AgCl) at pH 5.5. The response showed a surface-controlled electrode process with an electron transfer rate constant of 0.91 sec?1 determined in the scan rate range from 10 to 100 mV/sec. The GOD immobilized in DNA/chitosan membrane retained its biocatalytic activity and stability. The immobilized GOD could electrocatalyze the reduction of dissolved oxygen and resulted in a great increase of the reduction peak current. Upon the addition of glucose, the reduction peak current decreased, which could be used for glucose detection with a sensitivity of 0.48 μA/(mmol/L), a linear range from 0.04 to 2.28 mmol/L and a detection limit of 0.04 mmol/L at a signal-to-noise ratio of 3. The sensor could exclude the interference of commonly coexisted uricacid and ascorbic acid. 相似文献
826.
827.
828.
环境友好季铵盐杀菌剂的合成与抗菌特性 总被引:1,自引:0,他引:1
为了在提高季铵盐的杀菌活性的同时消除其在使用过程中对环境的二次污染,合成了一种可生物降解的新型双子季铵盐杀菌剂,1,5-(戊撑)双(N,N`-乙酸十二酯溴化铵)[略作:PDA]。利用二甲基甘氨酸和月桂醇的酯化反应得到了N,N-二甲基甘氨酸酯,再使用1,5-二溴戊烷将其季铵化得到目的物,经1H-NMR检测确认了合成物的结构。以最小抑菌浓度为指标评价了PDA的抗菌特性,并以活性污泥法评价了其生物降解特性。结果表明,与目前最广泛使用的季铵盐杀菌剂苯扎氯铵(BAC)相比较,无论是对于革兰氏阳性菌还是阴性菌PDA都具有更高的杀菌活性,平均MIC为3.11μmol/L。PDA还改善了一般季铵盐的环境稳定性,其抗菌力基本不受环境pH和温度的影响。PDA具有良好的生物降解性,在实验条件下第8天就可以达到100%的降解,相对于具有相似双链结构的季铵盐N,N`-二甲基-N,N`-双十二烷基氯化铵(D1221)提高了一倍。 相似文献
829.
830.