全文获取类型
收费全文 | 148篇 |
免费 | 3篇 |
专业分类
化学 | 132篇 |
晶体学 | 11篇 |
数学 | 4篇 |
物理学 | 4篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 7篇 |
2012年 | 10篇 |
2011年 | 14篇 |
2010年 | 10篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有151条查询结果,搜索用时 31 毫秒
121.
Maruthachalam Mohanraj Ganesan Ayyannan Gunasekaran Raja Chinnasamy Jayabalakrishnan 《应用有机金属化学》2016,30(7):550-560
Three ruthenium(II) hydrazone complexes of composition [RuCl(CO)(PPh3)2L] were synthesized from the reactions of [RuHCl(CO)(PPh3)3] with hydrazones derived from 4‐methoxybenzhydrazide and 4‐formylbenzoic acid (HL1), 4‐methylbenzaldehyde (HL2) and 2‐bromobenzaldehyde (HL3). The synthesized hydrazone ligands and their metal complexes were characterized using elemental analysis and infrared, UV–visible, NMR (1H, 13C and 31P) and mass spectral techniques. The hydrazone ligands act as bidentate ones, with O and N as the donor sites, and are predominantly found in the enol form in all the complexes studied. The molecular structures of the ligands HL1, HL2 and HL3 were determined using single‐crystal X‐ray diffraction. The interactions of the ligands and the complexes with calf thymus DNA were studied using absorption spectroscopy and cyclic voltammetry which revealed that the compounds could interact with calf thymus DNA through intercalation. The DNA cleavage activity of the complexes was evaluated using a gel electrophoresis assay which revealed that the complexes act as good DNA cleavage agents. In addition, all the complexes were subjected to antioxidant assay, which showed that they all possess significant scavenging activity against 2,2‐diphenyl‐2‐picrylhydrazyl, OH and NO radicals. The in vitro cytotoxic effect of the complexes examined on cancerous cell lines (HeLa and MCF‐7) showed that the complexes exhibit substantial anticancer activity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
122.
Natarajan Thilagavathi Chinnasamy Jayabalakrishnan 《Central European Journal of Chemistry》2010,8(4):842-851
Ru(III) complexes of the type [RuXB(L)2] have been prepared by the reaction of 3,4-dihydropyrimidin-2(1H)-ones/thiones (HL1–HL4) with the precursors of the type [RuX3B3] where X=Cl or Br; B=PPh3 or AsPh3 and L is the deprotonated ligand. The synthesized complexes were characterized by physico-chemical methods, electrochemical
and magnetic moment data. The catalytic efficiency of the complexes were examined in the oxidation of alcohols and antimicrobial
studies were also carried out.
相似文献
123.
A new series of isatin semicarbazide derivatives(7a-7j) were synthesized and characterized by spectroscopic means and elemental analysis.Analgesic and anti-inflammatory screening was performed using tail-flick technique and the carrageenan-induced foot paw edema test respectively.The ulcerogenicity was also determined for all the compounds.Some of the compounds showed moderate enhancement of the activity.Among the synthesized derivatives,compound 7d showed higher analgesic, antiinflammatory and one-third of ulcer index of the reference drug. 相似文献
124.
Beermohamed Vinosha Subbu Perumal Packianathan Thomas Muthiah Kaliyaperumal Thanigaimani 《合成通讯》2013,43(14):1964-1973
The Michael addition of nitromethane to (Z,Z)-2,2′-thiobis(1,3-diarylprop-2-en-1-ones) in the presence of NaOEt in dimethylformamide (DMF)/alcohol under thermal conditions affords a diastereomeric mixture of 2a,6e-diaroyl-3a,5e-diaryl-4e-nitrothianes and 2e,6e-diaroyl-3e,5e-diaryl-4e-nitrothianes with a dr of ~3:1/4:1 respectively. This reaction under microwave irradiation in DMF/alcohol afforded solely 2a,6e-diaroyl-3a,5e-diaryl-4e-nitrothianes, disclosing enhancement of stereoselectivity by microwaves. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
125.
Chinnasamy Mani Jeyaperumal Selvakumari YeonSoo Han YongHun Jo Krishnaraj Thirugnanasambantham Somaiah Sundarapandian Subbiah Poopathi 《Applied biochemistry and biotechnology》2018,184(4):1094-1105
A marine Bacillus cereus (VCRC B540) with mosquitocidal effect was recently reported from red snapper fish (Lutjanus sanguineous) gut and surface layer protein (S-layer protein, SLP) was reported to be mosquito larvicidal factor. In this present study, the gene encoding the surface layer protein was amplified from the genomic DNA and functionally characterized. Amplification of SLP-encoding gene revealed 1,518 bp PCR product, and analysis of the sequence revealed the presence of 1482 bp open reading frame with coding capacity for a polypeptide of 493 amino acids. Phylogenetic analysis revealed with homology among closely related Bacillus cereus groups of organisms as well as Bacillus strains. Removal of nucleotides encoding signaling peptide revealed the functional cloning fragment of length 1398 bp. Theoretical molecular weight (51.7 kDa) and isoelectric point (5.99) of the deduced functional SLP protein were predicted using ProtParam. The amplified PCR product was cloned into a plasmid vector (pGEM-T), and the open reading frame free off signaling peptide was subsequently cloned inpET-28a(+) and expressed in Escherichia coli BL21 (DE3). The isopropyl-β-D-thiogalactopyranoside (IPTG)-induced recombinant SLP was confirmed using western blotting, and functional SLP revealed mosquito larvicidal property. Therefore, the major findings revealed that SLP is a factor responsible for mosquitocidal activity, and the molecular characterization of this toxin was extensively studied. 相似文献
126.
A study on degradation of germanium coating on Kapton used for spacecraft sunshield application 下载免费PDF全文
A. Carmel Mary Esther Arjun Dey N. Sridhara B. Yougandar Parthasarathi Bera Chinnasamy Anandan Dinesh Rangappa Anand Kumar Sharma 《Surface and interface analysis : SIA》2015,47(13):1155-1160
Sunshield membranes made of germanium‐coated black polyimide (GBP) or Kapton are often used on the reflector/transmitter antenna of satellites for thermal control applications. However, the germanium top layer is prone to degrade during ground storage and implementation. Hence, vacuum/inert gas‐sealed packaging is required for storing the membranes, followed by a staggered fabrication schedule as the shelf‐life of the GBP is identified as only ~6 months. In the present study, microstructural, thermo‐optical, and electrical properties along with X‐ray photoelectron spectroscopy (XPS) studies for evaluating oxidation states of the as‐received and degraded GBP films have been investigated thoroughly. The radio frequency (RF) loss behavior of both the films has also been studied for S band (2.5–3.5 GHz), Ku band (10.5–14.5 GHz), and Ka band (30–35 GHz). Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
127.
Allylation of 2-aminophenol-derived aldimines using allyltrichlorosilane under catalyst free conditions has been developed. This reaction afforded the corresponding homoallylic amines in good to excellent yields (68–94%). The salicylaldehyde-derived aldimines as well as benzoylhydrazone also found to react with allyltrichlorosilane smoothly under the same conditions, to furnish the corresponding homoallylic amine derivatives. This study suggests that the phenolic –OH group acts as an anchoring group for the transfer of allyl group from allyl silane reagent. 相似文献
128.
Periasamy Devi Jeyaraman Selvaraj Nirmalram Packianathan Thomas Muthiah 《Journal of chemical crystallography》2011,41(11):1624-1629
Abstract
Two nearly isostructural pseudopolymorphic forms of pyrimethaminium terephthalate have been synthesized and their supramolecular architectures analyzed. In both the crystals, the protonated pyrimethamine (PMN) cation interacts with the carboxylate anion via N–H···O hydrogen bonds to form the robust R22(8) motif. The centrosymmetrically (N–H···N) paired PMN cations are bridged on either sides by interaction of the solvent molecules with the amino groups (N–H···O) of PMN cations. The combination of two R22(8) motifs formed between the PMN cations and PMN cation solvent, leads to the formation of the complementary DADA (D = hydrogen bonded donor, A = hydrogen bonded acceptor) array of quadruple hydrogen bonds. The solvent molecule further interacts with the corresponding anion via O–H···O hydrogen bonds. Moreover, both the solvates exhibit several edge to face stacking interactions. They have in common, two C–H···π interactions; one between the symmetry related cations and other between the cation and anion. The molecular packing of the ethanol solvate is further strengthened by C–H···O and C–H···π interaction between the solvent and the ions. 相似文献129.
Edward-Sam Edwin Prabhakaran Vasantha-Srinivasan Sengottayan Senthil-Nathan Muthiah Chellappandian Sengodan Karthi Radhakrishnan Narayanaswamy Vethamonickam Stanley-Raja Haridoss Sivanesh Ramakrishnan Ramasubramanian Asma A. Al-Huqail Faheema Khan Patcharin Krutmuang Ahmed Abdel-Megeed Aml Ghaith Chae-Hoon Paik 《Molecules (Basel, Switzerland)》2021,26(19)
Spodoptera litura Fab. is a polyphagous pest causing damage to many agriculture crops leading to yield loss. Recurrent usage of synthetic pesticides to control this pest has resulted in resistance development. Plant-derived diterpenoid compound andrographolide was isolated from the leaves of Andrographis paniculata. It was analysed by gas chromatography-mass spectroscopy and quantified by HPLC. Nutritional indices and digestive enzymatic profile were evaluated. Third, fourth and fifth instar larvae were treated with different concentrations of andrographolide. At 3, 6 and 9 ppm-treated concentrations the larvae showed decreased RGR, RCR, ECI, ECD values with adverse increase in AD. The digestive enzymes were significantly inhibited when compared with control. Conspicuously, andrographolide showed pronounced mortality of S. litura by inhibition of enzyme secretion and intake of food. The binding ability of andrographolide with CYTP450 showed high affinity with low binding energy. Andrographolide has the potential to be exploited as a biocontrol agent against S. litura as an eco-friendly pesticide. 相似文献
130.
Thermal properties of polyvinyl alcohol 总被引:1,自引:0,他引:1