全文获取类型
收费全文 | 125篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
化学 | 113篇 |
晶体学 | 8篇 |
力学 | 1篇 |
数学 | 7篇 |
物理学 | 3篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 12篇 |
2021年 | 11篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 11篇 |
2012年 | 4篇 |
2011年 | 11篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 10篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2000年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
排序方式: 共有132条查询结果,搜索用时 15 毫秒
41.
Afzal Shah Victor C. Diculescu Niaz Muhammad Rumana Qureshi Saqib Ali Ana Maria Oliveira‐Brett 《Electroanalysis》2010,22(1):121-127
The electrochemical behavior of Na‐salt of 2‐methyl‐3‐(4‐nitrophenyl)acrylate (NPA) and its reduction product was studied by cyclic (CV), differential pulse(DPV) and square wave voltammetry (SWV) using a glassy carbon electrode (GCE). The results revealed that NPA is irreversibly reduced leading to the formation of a reduction product (PNPA). For pH<9.0 the peak potential was linearly dependent on pH. For pH>9.0 the peak potential was pH‐independent and the value of pKb≈9.0 was determined. The adsorbed PNPA exhibited reversible redox reaction. The reduction of PNPA was pH dependent. To ensure that the electrochemical behavior of NPA is due to the reducible moiety, NO2, closely related compounds to NPA were also studied, and a redox mechanism was proposed for NPA. 相似文献
42.
Synthesis characterization and biological study of diorganotin(IV) complexes of monomethyl phthalate
Rehman W Baloch MK Badshah A Ali S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(3-4):689-694
The synthesis and characterization of new coordination compounds of some organotin(IV) chlorides with monomethyl phthalate is reported; the ligand molecules appear to be bound to the tin atom through carbonyl oxygen atoms. Their structures have been characterized by elemental analyses, molar conductance, and bonding in these complexes is discussed in terms of their IR, (1)H, (13)C, (119)Sn NMR and (119 m)Sn M?ssbauer spectral studies. The spectroscopic results obtained are in full agreement with the proposed 2:1 stoichiometry. The complexes soluble in DMSO have been screened against a wide spectrum of bacteria and the results obtained are quite promising. The LD(50) values have also been determined in the albino rats. Some of the complexes also exhibit high anti-inflammatory activity. 相似文献
43.
A weak Galerkin finite element method for the second order elliptic problems with mixed boundary conditions
下载免费PDF全文
![点击此处可从《Journal of Applied Analysis & Computation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Saqib Hussain Nolisa Malluwawadu Peng Zhu 《Journal of Applied Analysis & Computation》2018,8(5):1452-1463
In this paper, a weak Galerkin finite element method is proposed and analyzed for the second-order elliptic equation with mixed boundary conditions. Optimal order error estimates are established in both discrete $H^1$ norm and the standard $L^2$ norm for the corresponding WG approximations. The numerical experiments are presented to verify the efficiency of the method. 相似文献
44.
Sadiq-ur-Rehman Saqib Ali Moazzam H. Bhatti 《Journal of organometallic chemistry》2005,690(5):1396-1408
Nine organotin esters, Me2SnL21, Me3SnL 2, n-Bu2SnL23, n-Bu3SnL 4, Ph3SnL 5, (PhCH2)2SnL26, [(Me2SnL)2O]27, Et2SnL28 and n-Oct2SnL29, of (E)-3-(3-fluorophenyl)-2-(4-chlorophenyl)-2-propenoic acid, HL have been synthesized and characterized by elemental analysis, IR, Multinuclear NMR (1H, 13C and 119Sn) and mass spectrometry. The geometry around the tin atom has been deduced and compared both in solution and solid states. The crystal structure of compound 5 has been determined by X-ray single crystal analysis, which shows a tetrahedral geometry around the tin atom with space group . These compounds have also been screened for bactericidal, fungicidal activities and cytotoxicity data. 相似文献
45.
The mechanism of the fluxional process occurring in dimeric tetraorganodicarboxylato stannoxanes is presented on the basis of multinuclear NMR studies carried out in noncoordinating solvents. This fluxional process is a consequence of rapid migration of carboxylate groups from one tin atom to the other. It has been proposed that larger carboxylates will also execute this behavior. The effect of cis and trans positions on the fluxional process is discussed. The fluxional process is very fast and could not be stopped even at low temperatures, as measured on the NMR time scale. © 1996 John Wiley & Sons, Inc. 相似文献
46.
Fiaz Ahmad Saqib Ali Masood Parvez Arshad Munir M. Mazhar Khalid M. Khan Tasadaq Ali Shah 《Heteroatom Chemistry》2002,13(7):638-649
Eight tri‐ and diorganotin(IV) carboxylates with general formulae R3SnL and R2SnL2 (where R = CH3, n‐C4H9, C6H5, C7H7, and L = 2′,4′‐difluoro‐4‐hydroxy‐[1,1′]‐biphenyl‐3‐carboxylic acid) were synthesized and characterized by UV–vis, IR, conductance, multinuclear (1H, 13C, and 119Sn) NMR spectroscopy, and mass spectrometry. The crystal structure of [(CH3)3Sn(C13H7O3F2)] indicates that the tin atom in the asymmetric unit exists in a trigonal bipyramidal geometry having a space group Pbca with an orthorhombic crystal system. These complexes were also screened for their antibacterial and antifungal activities. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:638–649, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10057 相似文献
47.
Muhammad Umair Saqib Jabbar Mustapha M. Nasiru Zhaoxin Lu Jianhao Zhang Muhammad Abid Mian Anjum Murtaza Marek Kieliszek Liqing Zhao 《Molecules (Basel, Switzerland)》2021,26(22)
Ultrasound-assisted extraction (UAE) was used to extract carotenoids from the carrot pomace. To investigate the effect of independent variables on the UAE, the response surface methodology (RSM) with central-composite design (CCD) was employed. The study was conducted with three independent variables including extraction time (min), temperature (°C), and ethanol concentration (%). The results showed that the optimal conditions for UAE were achieved with an extraction time of 17 min, temperature of 32 °C, and ethanol concentration of 51% of total carotenoids (31.82 ± 0.55); extraction time of 16 min, temperature of 29 °C, and ethanol concentration of 59% for a combination of β-carotene (14.89 ± 0.40), lutein (5.77 ± 0.19), and lycopene (2.65 ± 0.12). The non-significant (p > 0.05) correlation under optimal extraction conditions between predicted and experimental values suggested that UAE is the more productive process than conventional techniques for the extraction of carotenoids from the carrot pomace. 相似文献
48.
49.
50.