全文获取类型
收费全文 | 145篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
化学 | 97篇 |
力学 | 4篇 |
数学 | 13篇 |
物理学 | 38篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2017年 | 2篇 |
2016年 | 10篇 |
2015年 | 5篇 |
2014年 | 10篇 |
2013年 | 11篇 |
2012年 | 17篇 |
2011年 | 14篇 |
2010年 | 12篇 |
2009年 | 5篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1974年 | 2篇 |
1965年 | 1篇 |
1903年 | 1篇 |
排序方式: 共有152条查询结果,搜索用时 15 毫秒
91.
Ban Zhen Hong Lau Kok Keong Azmi Mohd Shariff 《Continuum Mechanics and Thermodynamics》2016,28(3):655-668
The employment of different mathematical models to address specifically for the bubble nucleation rates of water vapour and dissolved air molecules is essential as the physics for them to form bubble nuclei is different. The available methods to calculate bubble nucleation rate in binary mixture such as density functional theory are complicated to be coupled along with computational fluid dynamics (CFD) approach. In addition, effect of dissolved gas concentration was neglected in most study for the prediction of bubble nucleation rates. The most probable bubble nucleation rate for the water vapour and dissolved air mixture in a 2D quasi-stable flow across a cavitating nozzle in current work was estimated via the statistical mean of all possible bubble nucleation rates of the mixture (different mole fractions of water vapour and dissolved air) and the corresponding number of molecules in critical cluster. Theoretically, the bubble nucleation rate is greatly dependent on components’ mole fraction in a critical cluster. Hence, the dissolved gas concentration effect was included in current work. Besides, the possible bubble nucleation rates were predicted based on the calculated number of molecules required to form a critical cluster. The estimation of components’ mole fraction in critical cluster for water vapour and dissolved air mixture was obtained by coupling the enhanced classical nucleation theory and CFD approach. In addition, the distribution of bubble nuclei of water vapour and dissolved air mixture could be predicted via the utilisation of population balance model. 相似文献
92.
Nurfatihah Che Abd Rashid Nor Hafizah Ngajikin Asrul Izam Azmi Rashidah Arsat Suhaila Isaak Noran Azizan Cholan Nur Ellina Azmi 《中国光学快报(英文版)》2019,(8)
A spectrophotometer with an LED as the light source for uric acid detection is proposed in this work. The mechanism of uric acid detection is based on energy absorbed by sodium urate, which is a chemical product of uric acid and sodium hydroxide solution. For the performance validation, comparison between the spectrophotometer with an LED and halogen lamp is carried out. Measurement results suggest that the spectrophotometer system with LED light has better sensitivity than that with halogen light. At a 460 nm wavelength,the sensitivity for the spectrophotometer with an LED is 0.0046 dL/mg, which is 73% higher than that with halogen light that records 0.0012 dL/mg. This enhanced sensitivity is attributed to the higher luminous efficacy of the LED light beam. As a result, a larger amount of flux interacts with the sample, leading to the sensitivity enhancement. The spectrophotometer with an LED is also applied for the detection of uric acid in a real human urine sample. Based on the experimental data at a 460 nm wavelength, the method manages to achieve the sensitivity of 0.0016 dL/mg, accuracy of 96.01%, limit of detection of 4.79 mg/dL, and limit of quantification of 14.52 mg/dL. These findings show that the use of LED as the input light source is promising for the spectrophotometer. 相似文献
93.
Abu Bakar Mohamad Hafizi Azmi Mohamad Nurul Shariff Khairul Anuar Tan Joo Shun 《Applied biochemistry and biotechnology》2019,188(1):241-259
Applied Biochemistry and Biotechnology - Withaferin A (WA), a bioactive constituent derived from Withania somnifera plant, has been shown to exhibit many qualifying properties in attenuating... 相似文献
94.
95.
Geometrical characterizations are given for the tensor R⋅S, where S is the Ricci tensor of a (semi-)Riemannian manifold (M,g) and R denotes the curvature operator acting on S as a derivation, and of the Ricci Tachibana tensor ∧g⋅S, where the natural metrical operator ∧g also acts as a derivation on S. As a combination, the Ricci curvatures associated with directions on M, of which the isotropy determines that M is Einstein, are extended to the Ricci curvatures of Deszcz associated with directions and planes on M, and of which the isotropy determines that M is Ricci pseudo-symmetric in the sense of Deszcz. 相似文献
96.
97.
The apoptotic effect of 1's-1'-acetoxychavicol acetate from Alpinia conchigera on human cancer cells
Awang K Azmi MN Aun LI Aziz AN Ibrahim H Nagoor NH 《Molecules (Basel, Switzerland)》2010,15(11):8048-8059
1'-(S)-1'-Acetoxychavicol acetate (ACA) isolated from the Malaysian ethno-medicinal plant Alpinia conchigera Griff. was investigated for its potential as an anticancer drug. In this communication, we describe the cytotoxic and apoptotic properties of ACA on five human tumour cell lines. Data from MTT cell viability assays indicated that ACA induced both time- and dose-dependent cytotoxicity on all tumour cell lines tested and had no adverse cytotoxic effects on normal cells. Total mortality of the entire tumour cell population was achieved within 30 hrs when treated with ACA at 40.0 μM concentration. Flow cytometric analysis for annexin-V and PI dual staining demonstrated that cell death occurred via apoptosis, followed by secondary necrosis. The apoptotic effects of ACA were confirmed via the DNA fragmentation assay, in which consistent laddering of genomic DNA was observed for all tumour cell lines after a 24 hrs post-treatment period at the IC(50) concentration of ACA. A cell cycle analysis using PI staining also demonstrated that ACA induced cell cycle arrest at the G(0)/G(1) phase, corresponding to oral tumour cell lines. In conclusion, ACA exhibits enormous potential for future development as a chemotherapeutic drug against various malignancies. 相似文献
98.
We obtain the inhomogeneous invariance quantum group for the multi-dimensional q-deformed bosonic Newton oscillator algebra. The homogenous part of this quantum group is given by the multiparameter quantum
group $
GL_{X;q_{ij} }
$
GL_{X;q_{ij} }
of Schirrmacher where q
ij’s take some special values. We find the R-matrix which gives the non-commuting structure of the quantum group for the two dimensional case. 相似文献
99.
Ali. E. I. Elkhalifah Saikat Maitra M. Azmi Bustam T. Murugesan 《Journal of Thermal Analysis and Calorimetry》2012,110(2):765-771
Different cationic forms of montmorillonite, mainly K-, Na-, Ca- and Mg-montmorillonites were intercalated in this study via ion exchange process with mono-, di-, and triethanolammonium cations. The developed samples were characterized by TG, XRD, and CHNS techniques. Thermogravimetric study of ammonium-montmorillonites shows three thermal transition steps, which are attributable to the volatilization of the physically adsorbed water and dehydration, followed by the decomposition of the intercalated ammonium cations and dehydroxylation of the structural water of the modified clay, respectively, while untreated and cationic forms of montmorillonite showed only two decomposition steps. The type of ammonium cation has affected both desorption temperature (Position) and the amount of the adsorbed water (intensity). XRD results show a stepwise change in the crystallographic spacings of montmorillonite with the molar mass of ammonium cation, reflecting a change in the structure of the clay. CHNS data confirm the intercalation of ammonium cations into the interlayer space of montmorillonite and corroborate the effect of the molar mass of ammonium cation on the amount adsorbed by the clay. 相似文献
100.
Determination of Vanadium(IV) and Vanadium(V) in Benfield Samples by IEC with Conductivity Detection
In this study, the determination of vanadium valence state, V(IV) and V(V) has been achieved using ion-exchange chromatography with conductivity detector. In this method, V(IV) was determined as V(IV)-EDTA complex and V(V) as vanadate ion. Determination of V(IV) was successfully done using 3 mM carbonate/bicarbonate/EDTA at pH 8.6 as the eluent. The additive, EDTA in the mobile phase did not seem to interfere with the V(IV) analysis. The detection of V(V) was achieved with 5 mM disodium hydrogen phosphate buffer at pH 10.4. A linear calibration graph over VO3 ? and V(IV) with concentration ranges 5–15 mg L?1 gave the detection limit at 0.09 and 0.1 mg L?1, respectively. Both V(IV) and V(V) were successfully determined in Benfield sample, with concentrations of V(IV) and V(V) at 4 and 11,000 mg L?1, respectively. 相似文献