首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   181篇
  免费   18篇
  国内免费   3篇
化学   171篇
晶体学   4篇
力学   1篇
数学   9篇
物理学   17篇
  2023年   2篇
  2022年   6篇
  2021年   8篇
  2020年   9篇
  2019年   11篇
  2018年   12篇
  2017年   8篇
  2016年   13篇
  2015年   13篇
  2014年   10篇
  2013年   12篇
  2012年   12篇
  2011年   16篇
  2010年   8篇
  2009年   9篇
  2008年   12篇
  2007年   9篇
  2006年   6篇
  2005年   6篇
  2004年   7篇
  2003年   1篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1992年   1篇
  1991年   2篇
  1988年   1篇
  1979年   1篇
  1977年   1篇
  1971年   2篇
  1969年   1篇
排序方式: 共有202条查询结果,搜索用时 15 毫秒
141.
In vitro study to evaluate toxic effects of metal oxides nanoparticles on energy producing cycle was conducted. In this study oxidation of sodium succinate in aqueous solution was investigated by using potassium ferricyanide as an oxidizing agent. Kinetic measurements were carried out on kinetic mode of spectrophotometer at λmax 420 nm. Effect of different metal oxides (MgO and CaO) nanoparticles was observed on the oxidation of succinate at 25 ± 0.5 °C. These metal oxides nanoparticles were prepared by hydrothermal method and their characterization were done by using FTIR, TGA, SEM‐EDX, TEM and XRD. Kinetic results indicated that these nanoparticles inhibit the conversion of succinate into fumerate. The inhibition is directly dependent on particle size of the nanoparticles and it was observed that particle size is inversely related to the oxidation rate of succinate. It was concluded at the end that elevated concentrations of metal oxides nanoparticles can severely affect the Krebs cycle by inhibiting succinate oxidation and lead to various metabolic disorders.  相似文献   
142.
Gaussia luciferase assay was used to measure the anti‐hepatitis C (anti‐HCV) potency of tributyltin(IV)[3‐(3′,5′‐dimethylphenylamido)propanoate] in infected Huh 7.5 cells (human hepatocellular cell). Interaction of the organotin(IV) complex with cetyl N,N,N‐trimethylammonium bromide (CTAB) micelles was studied using UV–visible and steady‐state florescence spectroscopy. The anti‐HCV study showed a log IC50 value of 0.96 nm for the complex. The complex–CTAB interaction parameter showed that partition of the complex from bulk water to the CTAB micelle was a spontaneous process, and the red shift in visible spectra of the complex confirmed its increased solubility into micelles. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
143.
Schiff base tetraazamacrocyclic ligand, L (C(40)H(28)N(4)) and its complexes of types, [MLX(2)] and [CuL]X(2) (M=Co(II), Ni(II), Zn(II); X=Cl(-), NO(3)(-)) were synthesized and characterized by elemental analyses, mass, (1)H NMR, IR, UV-vis, magnetic susceptibility and molar conductance data. An octahedral geometry has been proposed for all the complexes except the copper(II) complexes which have a square planar environment. The reducing power of the Co(II) and Cu(II) complexes have been checked and compared. The ligand (L) and its complexes have also been screened against different fungi and bacteria in vitro.  相似文献   
144.
The Schiff base ligand, N,N'-bis-(2-pyridinecarboxaldimine)-1,8-diaminonaphthalene (L), obtained by the condensation of 2-pyridinecarboxaldehyde and 1,8-diaminonaphthalene, has been used to synthesize the mononuclear complexes of the type [MLCl(2)] [M=Co(II), Ni(II), Cu(II) and Zn(II)]. The newly synthesized ligand (L) and its complexes have been characterized on the basis of results of elemental analysis, molar conductance, magnetic susceptibility measurements, Job's method and spectroscopic studies viz., FT-IR, Mass, (1)H and (13)C NMR. The UV-vis and magnetic moment data revealed an octahedral geometry around Co(II), Ni(II) and Cu(II) ions and conductivity data show a non-electrolytic nature of the complexes. Absorption and fluorescence spectroscopic studies support that Cu(II) complex exhibits significant binding to calf thymus DNA.  相似文献   
145.
Organometallic macromolecules such as ferrocenyl bis‐pyrazoline ( 2 , 3 ) and bis‐pyrimidine ( 4 , 5 ) derivatives were synthesized by reacting ferrocenyl bis‐chalcone 1 with thiosemicarbazide/phenylhydrazine/guanidine hydrochloride/thiourea, respectively, under microwave irradiation. Ferrocenyl bis‐chalcone 1 was synthesized by reacting acetyl ferrocene with terephthalaldehyde. Synthesized compounds were characterized by using IR, 1H NMR, 13C NMR, EI‐MS, and elemental analysis. In vitro antibacterial activity against two Gram‐negative and two Gram‐positive bacteria was determined by the disc diffusion assay. Moreover, minimum inhibition concentrations were also measured with reference to chloramphenicol. Thioamide functionally containing ferrocenyl bis‐pyrazoline derivative 2 shows the best antibacterial activity on Escherichia coli and Salmonella typhimurium, among all tested compounds including the reference drug chloramphenicol. The structure–activity relationship is also developed by using computational calculations with density functional theory (DFT)/B3LYP method.  相似文献   
146.
Natural polymers have been extensively utilized in the past decades due to their outstanding features. Among these natural excipients, protein‐based polymers have superb features owing to their high drug binding capacity and biodegradability. Whey protein is a versatile protein‐based vehicle for drug delivery systems. It has been shown to be nontoxic, biocompatible, and biodegradable. Therefore, it has been considered as an ideal biomaterial for the design of advanced drug delivery systems. Protein‐based cargo acts as synthetic polymers counterpart for innovative delivery systems. The current review is mainly focused on application of whey proteins as an emerging carrier in drug delivery systems, achieved during the past.  相似文献   
147.
The carbon‐carbon and carbon‐heteroatom bond formation reactions are considered as a fundamental tool in synthetic organic chemistry. They have been effectively utilized in the synthesis of medicinally significant molecules, agrochemicals and valuable compounds in material sciences. This has been primarily enabled by highly efficient protocols arising from divergent mechanistic pathways. In this personal account, we aim to discuss some recent advances in carbon‐carbon or carbon‐heteroatom bond formation reactions to which our group has actively contributed. More specifically, this record focuses on the use of unsaturated carbon compounds for the construction of C?C and C?X bonds.  相似文献   
148.
Benzoylthiourea derivatives feature several donor atoms capable of coordinating to metal centers. We report here a series of Ru(η6p‐cymene) complexes employing benzoylthiourea derivatives as ligands. Such ligands often coordinate to metal centers through their S and O donor atoms. We isolated complexes where the ligands were mono‐ or bidentately coordinated to Ru involving the S donor atom and surprisingly in bidentate coordination mode a deprotonated thiourea nitrogen resulting in a 4‐membered ring structure around the metal center. DFT calculations were used to explain the differences in coordination behavior. These were complemented by stability studies and biological investigations of the compounds as anticancer agents. Several of the synthesized derivatives exhibited significant cell growth inhibitory activity, with the complexes featuring bidentate ligands being more potent than their monodentate counterparts. This can be explained by the higher stability of the former under the conditions employed in cell culture assays.  相似文献   
149.
In this paper the use of N-bromosuccinimide as a direct titrant for AS(III) has been described. Bordeaux red was used as an indicator. From 0.6–6.0 mg of AS(III) were analyzed, and the maximum relative standard deviation is 1.35% in case of 0.60 mg. The method is precise, accurate, and rapid.  相似文献   
150.
The application of FTIR spectroscopy to concentrated solutions of tetrolic acid shows, for the first time, a direct relationship between molecular self association in solution and H-bonded motifs in the subsequently crystallised solid phases.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号