全文获取类型
收费全文 | 121篇 |
免费 | 8篇 |
国内免费 | 3篇 |
专业分类
化学 | 40篇 |
晶体学 | 1篇 |
力学 | 4篇 |
数学 | 1篇 |
物理学 | 5篇 |
综合类 | 81篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 5篇 |
2009年 | 8篇 |
2008年 | 10篇 |
2007年 | 5篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有132条查询结果,搜索用时 15 毫秒
41.
本文通过对现行评价泥浆泥饼压缩性的三种方法:“泥饼渗透率法”、“泥饼针入度法”、“两次失水法”进行对比实验研究,考察了在常温静(动)态和高温静(动)态四种实验条件下泥浆泥饼可压缩性之间的对比关系。结果表明:以“两次失水法”,且以不倒泥浆两次失水法作为评价泥饼压缩性,方法简便,数据可信;得出泥饼的可压缩性是由弹性变形和塑性变形共同作用的结果。 相似文献
42.
将油菜籽饼在300~450℃范围内进行热解,分别获得22.4~28.4%的热解油;23.4~24.1%的热解水;26.3~36.6%的残留炭以及17.4~21.2%的气体。考察了热解温度对热解产率和热解油组成的影响。气相色谱,色-质联用以及差热分析表明,热解油含有大约50%的脂肪酸,其大致组成是12%的软酯酸、4%的硬酯酸、24%的反油酸以及45%的油酸。初步探讨了热转化机理。 相似文献
43.
44.
李淑华 《齐齐哈尔大学学报(自然科学版)》2000,16(4):82-83
本文就蓖麻籽榨油后所剩的物质-蓖麻饼中提取分离蛋白质进行了研究,采用正交设计方法,进行提取分离蛋白质的工艺实验,得到了蛋白质提取率在67.5%-93.1%的较佳工艺条件。 相似文献
45.
46.
《Arabian Journal of Chemistry》2014,7(5):758-769
This study was carried out in a laboratory scale to recover uranium from Uro area phosphate ore in the eastern part of Nuba Mountains in Sudan. Phosphate ore samples were collected, and analyzed for uranium abundance. The results showed that the samples contain a significant concentration of uranium with an average of 310.3 μg/g, which is 2.6 times higher than the world average of phosphate. The green phosphoric acid obtained from the samples was found to contain uranium in the range of 186–2049 μg/g, with an average of 603.3 μg/g, and about 98% of uranium content of the phosphate ore was rendered soluble in the phosphoric acid. An extraction process using 25% tributylphosphate, followed by stripping process using 0.5 M sodium carbonate reported that more than 98% of uranium in the green phosphoric acid exists as uranyl tricarbonate complex, moreover, sodic decomposition using 50% sodium hydroxide showed that about 98% of the uranium was precipitated as sodium diuranate concentrate that is known as the yellow cake (Na2U2O7). Further purification and calcinations of the yellow cake led to the formation of the orange powder of uranium trioxide (UO3). The chemical analysis of the obtained uranium concentrates; yellow cake and uranium trioxide proved their nuclear purity and that they meet the standard commercial specification. The obtained results proved that uranium from Uro phosphate ore was successfully recovered as uranium trioxide with an overall recovery percentage of 93%. 相似文献
47.
着重介绍了临涣选煤厂GPY200圆盘真空过滤机使用中存在的问题以及对真空过滤系统进行技术改造的措施,改造后的过滤机取得了良好的使用效果。 相似文献
48.
研究不同基质微生物在以油菜籽饼粕为原料的沼气发酵中对产气性能的影响.在30℃条件下以油菜籽饼粕为发酵原料,分别选取基质微生物比F/M(VS/VS)为0.20、0.15进行批量式发酵.结果表明,基质微生物比F/M(VS/VS)=0.20的实验组TS、VS产气率、总产气量及达到总产气量80%的发酵时间分别为165mL/g·TS、184mL/g·VS、2 310mL和4d,而F/M(VS/VS)=0.15的实验组分别为95mL/g·TS、106mL/g·VS、1 330mL和17d.因此,基质微生物比对油菜籽饼粕的沼气发酵有着较大影响. 相似文献
49.
膜过滤过程中污染物颗粒会不断在膜表面沉积从而形成滤饼,其所带来的通量下降使膜过滤效率下降.为分析微粒在沉积过程中的机理与影响因素,以单个微粒的受力为基础,建立了过滤过程中滤饼厚度的方程式,为尽量降低膜过滤阻力提供了理论参考. 相似文献
50.
In this research, the applicability of a new sorbent based on boronate affinity material is demonstrated. For this purpose, six strong polar nitrophenols were selected as models which are difficult to be extracted in neutral form (only based on hydrophobic interactions). The extracted nitrophenols were separated and determined by high-performance liquid chromatography with diode array detection. The sorbent was synthesized by in situ copolymerization of 3-acrylamidophenylboronic acid and divinylbenzene using dimethyl sulfoxide and azobisisobutyronitrile as porogen solvent and initiator, respectively. The effect of the preparation parameters in the polymerization mixture on extraction performance was investigated in detail. The size and morphology of the sorbent have been characterized via different techniques such as infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. The important parameters influencing the extraction efficiency were studied and optimized thoroughly. Under the optimum extraction conditions, the limits of detection (S/N = 3) and limits of quantification (S/N = 10) for the target nitrophenols were 0.097–0.28 and 0.32–0.92 μg/L, respectively. The precision of the proposed method was evaluated in terms of intra- and inter-assay variability calculated as RSD, and it was found that the RSDs were all below 9%. Finally, the developed method was successfully applied for environmental water samples such as wastewater, tap, lake and river water. The recoveries varied within the range of 71.2–115% with RSD below 11% in all cases. The results well demonstrate that the new boronate affinity sorbent can extract nitrophenols effectively through multi-interactions including boron–nitrogen coordination, hydrogen-bond and hydrophobic interactions between sorbent and analytes. 相似文献