全文获取类型
收费全文 | 71篇 |
免费 | 9篇 |
国内免费 | 8篇 |
专业分类
化学 | 63篇 |
晶体学 | 1篇 |
力学 | 12篇 |
数学 | 3篇 |
物理学 | 9篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 9篇 |
2019年 | 1篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2012年 | 8篇 |
2011年 | 4篇 |
2010年 | 2篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
排序方式: 共有88条查询结果,搜索用时 15 毫秒
11.
An immersed smoothed point interpolation method (IS‐PIM) for fluid‐structure interaction problems 下载免费PDF全文
An immersed smoothed point interpolation method using 3‐node triangular background cells is proposed to solve 2D fluid‐structure interaction problems for solids with large deformation/displacement placed in incompressible viscous fluid. In the framework of immersed‐type method, the governing equations can be decomposed into 3 parts on the basis of the fictitious fluid assumption. The incompressible Navier‐Stokes equations are solved using the semi‐implicit characteristic‐based split scheme, and solids are simulated using the newly developed edge‐based smoothed point interpolation method. The fictitious fluid domain can be used to calculate the coupling force. The numerical results show that immersed smoothed point interpolation method can avoid remeshing for moving solid based on immersed operation and simulate the contact phenomenon without an additional treatment between the solid and the fluid boundary. The influence from information transfer between solid domain and fluid domain on fluid‐structure interaction problems has been investigated. The numerical results show that the proposed interpolation schemes will generally improve the accuracy for simulating both fluid flows and solid structures. 相似文献
12.
利用哈密顿变分原理以及结构动静态构型的影响,建立了索-梁组合结构的约化运动学控制方程.考虑到边界条件和耦合连接条件,我们研究了体系的面内特征值问题.根据求解得到的面内特征值方程,并通过分段函数的引入,结构的模态函数可以被直接确定.随后,我们研究了参数垂跨比f,刚度比K和质量比m对面内固有频率的影响.研究发现从结构的频率谱图中可以看出频率跳跃现象是存在的,另外,频率穿越现象也是十分明显.随后,考虑到局部模态和整体模态,结合之前确定的特征值方程及分段振型函数,我们研究了索-梁组合结构可能的模态形状.最后,我们讨论了索-梁组合结构可能发生的内共振形式,比如面内1:1内共振形式以及1:2内共振形式.研究表明梁的静态构型不仅直接影响到耦合力连接条件,还将影响索-梁组合结构频率的确定. 相似文献
13.
14.
Zhiqian?Yang Monica?Argenziano Paolina?Salamone Elisa?Pirro Andrea?E.?Sprio Federica?Di Scipio Maria?E.?Carere Elena?Quaglino Federica?Cavallo Roberta?Cavalli Giovanni?N.?BertaEmail author 《Journal of inclusion phenomena and macrocyclic chemistry》2016,86(3-4):263-271
Trans-Resveratrol (RV) is a natural polyphenol characterized by interesting pleiotropic potentials and health benefits, but its administration is hampered by a unsatisfactory pharmacokinetics. Various approaches have been identified to circumvent it: among them, 2-hydroxypropyl-β-cyclodextrins (HPβCD) are valuable strategy. Here, we compare the employment of HPβCD based formulation with a resveratrol nanosupension (obtained by diluting a RV ethanol solution with PBS, added of 0.05 % hydroxyethylcellulose) to improve RV bioavailability after oral administration to mice. The inclusion of RV in HPβCD was confirmed by differential scanning calorimetry, Fourier transformed infrared spectroscopy, and phase solubility study. The two formulations were orally administered to BALB-c mice. RV concentrations in plasma and tissues were detected at different time (0–120 min) by HPLC method. HPβCD complexation mediate a approximately fourfold increment in plasma RV Cmax and approximately twofold augment of RV AUC0-120 in comparison with RV nanosuspension. Similar increased concentrations were observed in heart, liver, kidney and gut. In particular, HPβCD mediated a 5.5-folds increase of resveratrol concentration in the intestine, in comparison to the nanosuspension. In conclusion, based on our results, HPβCD complexation is a promising approach to increase the oral bioavailability of RV. Moreover, the achievement of high concentrations in gut suggested a potential employment of oral RV-HPβCD as anti-inflammatory/chemopreventive agent in this tissue. 相似文献
15.
A fluorophore capable of crossword puzzles and logic memory 总被引:4,自引:0,他引:4
16.
17.
Rhodium(I)-catalyzed C–P cross-coupling reaction with aryl iodides and acylphosphines was disclosed for a straight forward synthesis of triarylphosphines. The acylphosphines were successfully employed as both the phosphorus source and the ligand to the Rh(I) catalyst. The triarylphosphines could be afforded in a yield up to 98% with good toleration of wide functional groups. 相似文献
18.
In this review, we summary the design concepts and strategies of NIR fluorescent theranostics for the senserelease in living systems. In particular, molecularly NIR fluorescent theranostic prodrug is elucidated to address current challenges of real-time bioimaging and tumor-specific chemotherapy for personalized treatment. 相似文献
19.
确定主环是命名复杂桥环化合物的难点所在。我们介绍一种"剪断最短桥,显露最大环"的方法,可以帮助学生快速准确地确定最大环的位置,从而对复杂桥环化合物命名。 相似文献
20.
Preparation and quantification of the total phenolic products in Citrus fruit using solid‐phase extraction coupled with high‐performance liquid chromatography with diode array and UV detection 下载免费PDF全文
Siyu Zhao Yisong Shu Zhiqian Song Chun Wang Yunzhuo Dong Zhangchi Ning Dan He Menglei Wang Cheng Lu Yuanyan Liu Aiping Lu 《Journal of separation science》2016,39(19):3806-3817
Citrus fruit is an important health‐promoting food that is rich in dietary phenolic metabolites. Traditional Chinese medicines, such as Zhishi and Zhiqiao, come from young and immature fruits of Citrus cultivars. The preparation of diversified bioactive phenolic products and establishment of the corresponding quality control methodology are challenging and necessary. In the current study, four types of solid‐phase extraction sorbents for the enrichment and clean‐up of the phenolic matrix were evaluated. A solid‐phase extraction column coated with Strata‐X was finally used in the procedure. Twenty phenolic compounds were selected to evaluate the extraction performances of the sorbents using high‐performance liquid chromatography analysis. Under the optimized conditions, good linearities were obtained with R2 more than 0.9996 for all analytes with LODs of 0.04–1.012 μg/g. Intra‐ and interday relative standard deviation values were less than 3%, and the recovery was equal to or higher than 90.02%. Compared to non‐solid‐phase extraction process, the content of total phenolic products was elevated 35.55–68.48% with solid‐phase extraction. Finally, the developed and validated method was successfully applied to the discrimination of Zhishi samples from different species as well as Zhishi and Zhiqiao samples in different development stages. 相似文献