全文获取类型
收费全文 | 583篇 |
免费 | 65篇 |
国内免费 | 196篇 |
专业分类
安全科学 | 75篇 |
废物处理 | 89篇 |
环保管理 | 88篇 |
综合类 | 361篇 |
基础理论 | 73篇 |
污染及防治 | 122篇 |
评价与监测 | 18篇 |
社会与环境 | 14篇 |
灾害及防治 | 4篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 23篇 |
2021年 | 22篇 |
2020年 | 30篇 |
2019年 | 15篇 |
2018年 | 16篇 |
2017年 | 18篇 |
2016年 | 35篇 |
2015年 | 19篇 |
2014年 | 33篇 |
2013年 | 43篇 |
2012年 | 47篇 |
2011年 | 53篇 |
2010年 | 43篇 |
2009年 | 28篇 |
2008年 | 28篇 |
2007年 | 56篇 |
2006年 | 34篇 |
2005年 | 46篇 |
2004年 | 30篇 |
2003年 | 38篇 |
2002年 | 36篇 |
2001年 | 27篇 |
2000年 | 18篇 |
1999年 | 17篇 |
1998年 | 17篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
排序方式: 共有844条查询结果,搜索用时 531 毫秒
331.
1株高效去除氨氮的红假单胞菌的分离鉴定及特性 总被引:1,自引:0,他引:1
从云南某一沼泽地中分离筛选出1株可降解氨氮的光合细菌psb1,细胞形态及活细胞特征吸收光谱与红假单胞菌属(Rhodopseudomonas sp.)基本一致.光合细菌16S r DNA特异引物扩增序列比对结果表明,菌株psb1与Rhodopseudomonas sp.同源性达99%,且细菌叶绿素Y亚基的蛋白质序列比对结果表明,菌株psb1与Rhodopseudomonas palustris相似性最大,为99%.但生理生化特征及其主要脂肪酸分析发现菌株psb1与Rhodopseudomonas palustris有较大差异,菌株psb1不能利用葡萄糖和甘露醇等,且含特定脂肪酸C_(18:1ω6c).单一因素实验结果表明:菌株psb1最适生长温度和p H分别为40℃和7.0,最优生长氮源为酵母膏;初始p H为6.0~7.0,30℃条件下厌氧光照培养,投加0.4%的psb1菌剂对模拟废水中氨氮的去除率达99%以上.说明光合细菌psb1为Rhodopseudomonas属的一个新菌,能高效去除氨氮,在景观水体水质调控中具有重要应用前景. 相似文献
332.
高效液相色谱法测定腈纶废水中的特征污染物 总被引:1,自引:0,他引:1
N,N-二甲基乙酰胺和丙烯腈为腈纶生产废水中的两种特征污染物,对二者的准确测定至关重要;文章优化了高效液相色谱法测定二者混合液的操作条件:流动相配比、流动相流速、柱温,实现了高效液相色谱法对DMAC和丙烯腈的完全分离。结果表明:色谱柱:Agilent Eclipse XDB-CN(5μm×4.6mm×150mm)不变的情况下,柱温为25℃;流动相,水∶甲醇为70∶30;流速为0.6mL/min时,二者的分离度达到5.45,能对二者进行有效的完全分离。 相似文献
333.
通过化学法合成叔胺化纳米SiO2(SiO2-N)和聚对氯甲基苯乙烯(PCMS),利用SiO2-N中的叔胺基与PCMS中的氯甲基反应,生成大分子季铵化纳米SiO2(SiO2-N+@PCMS),通过进一步与聚偏氟乙烯(PVDF)共混,以相转化法制备纳米荷电改性的PCMS/PVDF支撑底膜,进而采用界面聚合法制备正渗透(FO)复合膜.采用红外光谱、扫描电镜、zeta电位计和接触角测定仪等对支撑底膜和FO膜表面的化学结构、形貌、荷电性和亲水性等进行了分析,并通过正渗透装置对膜的分离性能进行了测试.结果表明该改性正渗透膜具有较好的荷正电性能,且随着SiO2-N的加入可以有效提高正渗透膜的亲水性和分离性能,添加2%的SiO2-N改性正渗透膜的纯水通量最高可达到22.76 L·m-2·h-1,对四环素的截留率可达到98.5%,经3次水-四环素-水循环过滤后,纯水通量恢复率仍然可达到9... 相似文献
334.
335.
336.
337.
A new physical method, namely boiling treatment, was developed to aid flotation separation of acrylonitrile–butadiene–styrene (ABS) and polystyrene (PS) plastics. Boiling treatment was shown to be effective in producing a hydrophilic surface on ABS plastic. Fourier Transform Infrared analysis was conducted to investigate the mechanism of boiling treatment of ABS. Surface rearrangement of polymer may be responsible for surface change of boiling treated ABS, and the selective influence of boiling treatment on the floatability of boiling treated plastics may be attributed to the difference in the molecular mobility of polymer chains. The effects of flotation time, frother concentration and particle size on flotation behavior of simple plastic were investigated. Based on flotation behavior of simple plastic, flotation separation of boiling treatment ABS and PS with different particle sizes was achieved efficiently. The purity of ABS and PS was up to 99.78% and 95.80%, respectively; the recovery of ABS and PS was up to 95.81% and 99.82%, respectively. Boiling treatment promotes the industrial application of plastics flotation and facilitates plastic recycling. 相似文献
338.
With large quantity of flux (Na2CO3), lead can be recovered from the funnel glass of waste cathode-ray tubes via reduction–melting at 1000 °C. To reduce flux cost, a technique to recover added flux from the generated oxide phase is also important in order to recycle the flux recovered from the reduction–melting process. In this study, the phase separation of sodium and the crystallization of water-soluble sodium silicates were induced after the reduction–melting process to enhance the leachability of sodium in the oxide phase and to extract the sodium from the phase for the recovery of Na2CO3 as flux. A reductive atmosphere promoted the phase separation and crystallization, and the leachability of sodium from the oxide phase was enhanced. The optimum temperature and treatment time for increasing the leachability were 700 °C and 2 h, respectively. After treatment, more than 90% of the sodium in the oxide phase was extracted in water. NaHCO3 can be recovered by carbonization of the solution containing sodium ions using carbon dioxide gas, decomposed to Na2CO3 at 50 °C and recycled for use in the reduction–melting process. 相似文献
339.
Helen Young 《Disasters》1987,11(2):102-109
A survey of thirty-four feeding programmes in Ethiopia and East Sudan was undertaken. Wie differences were found between the two countries and also within Ethiopia. Irrelugar general ration distribution was commonplace in Ethiopia, thus placing an extra strain on selective feeding programmes. The principal admission criteria to Selected Feeding Programmes (SFPs) were weight for height categories. The cut-off stages of the emergency. Useful compasirions between programmes were hampered by such differences, as well as by the different methods of reporting data.
The types of food usd in programmes depended on availability and included high energyu drinks, poridges, take-home pre-mixes and sometimes indigenous foods. A large number of foods e.g. cornedbedef, chicken paté, noodles, da4tes etc. Some added interesting variety and added nutritional value to the diet, while others caused more problems than they solved due to their low acceptability, inappropriate packaging, limited accompanying information and complex an costly preparation. The imlementation of food dination policies by donors and consignees regarding appropriate foodstuffs and their recommended use was considered to be the major solution to this problem. 相似文献
The types of food usd in programmes depended on availability and included high energyu drinks, poridges, take-home pre-mixes and sometimes indigenous foods. A large number of foods e.g. cornedbedef, chicken paté, noodles, da4tes etc. Some added interesting variety and added nutritional value to the diet, while others caused more problems than they solved due to their low acceptability, inappropriate packaging, limited accompanying information and complex an costly preparation. The imlementation of food dination policies by donors and consignees regarding appropriate foodstuffs and their recommended use was considered to be the major solution to this problem. 相似文献
340.
Determinationofpolycyclicaromatichydrocarbonswithsupercriticalfluidextractionandchromatography(SFE/SFC)YaoWeixi(ResearchCente... 相似文献