全文获取类型
收费全文 | 130篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
化学 | 96篇 |
晶体学 | 1篇 |
力学 | 2篇 |
数学 | 8篇 |
物理学 | 31篇 |
出版年
2023年 | 1篇 |
2022年 | 10篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 10篇 |
2014年 | 5篇 |
2013年 | 3篇 |
2012年 | 13篇 |
2011年 | 8篇 |
2010年 | 8篇 |
2009年 | 2篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 4篇 |
1998年 | 3篇 |
1996年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 6篇 |
排序方式: 共有138条查询结果,搜索用时 15 毫秒
101.
Rodrigo Beltrán-Suito Angela Pinedo-Flores Fabiola Bravo-Hualpa Jorge Ramos-Muñoz 《Journal of Dispersion Science and Technology》2019,40(6):901-908
Water-resistant MOF-235 was used to adsorb N,N-dimethylamine (DMA) from aqueous solutions. It was synthesized from terephthalic acid and FeCl3.6H2O under air-free conditions and characterized by its crystalline structure, functional groups and temperature resistance. The kinetic data results were best adjusted to the pseudo-second order model (R2>0.963). The best-fit isotherm, Langmuir model, suggested the adsorption of DMA is localized on homogenously distributed active sites on the surface. This fit was confirmed by the value of β?=?1 on the Redlich-Peterson model. Our study suggests that the manipulation of novel materials such as MOF-235 promises new avenues for water treatment solutions.
Schematic structure of MOF-235 and its application as adsorbent. 相似文献
102.
Triple channel sensing of Pb(II) ions by a simple multiresponsive ferrocene receptor having a 1-deazapurine backbone 总被引:1,自引:0,他引:1
A new redox, chromogenic, and fluorescent chemosensor molecule based on a deazapurine ring selectively senses aqueous Pb2+ in acetonitrile over other metal ions examined: redox shift (DeltaE1/2 = 0.15 V of the Fe(II)/Fe(III) redox couple), the colorless to orange color change, and an emission change of 620-fold, with an unprecedented detection limit of 2.7 microg L-1. The signal transduction occurs via a reversible CHEF with this inherent quenching metal ion. 相似文献
103.
Pitarresi G Tripodo G Calabrese R Craparo EF Licciardi M Giammona G 《Macromolecular bioscience》2008,8(10):891-902
Inulin was chosen as a starting polymer for biocompatible, pH-sensitive and biodegradable hydrogels. Three INUDVSA-TT hydrogels were obtained by crosslinking inulin derivatives with trimethylolpropane tris(3-mercaptopropionate) under varying conditions. The resulting hydrogels were cell compatible, as demonstrated by MTS and trypan blue exclusion assays acting on Caco-2 cells, and were biodegraded by inulinase and esterase, thus suggesting their use as colonic drug delivery systems. 2-Methoxyestradiol, an anti-cancer drug, was soaked in INUDVSA-TT hydrogels and its in vitro release and apoptotic effect on Caco-2 cells were evaluated. 相似文献
104.
Craparo EF Pitarresi G Bondì ML Casaletto MP Licciardi M Giammona G 《Macromolecular bioscience》2008,8(3):247-259
The preparation and characterization of surface-PEGylated polymeric nanoparticles are described. These systems were obtained by UV irradiation of PHM and PHM-PEG(2000) as an inverse microemulsion, using an aqueous solution of the PHM/PHM-PEG(2000) copolymer mixture as the internal phase and triacetin saturated with water as the external phase, and characterized by dimensional analysis, zeta-potential measurements and XPS. in vitro biological tests demonstrated their cell compatibility and their ability to escape from phagocytosis. Rivastigmine was encapsulated into the nanoparticle structure and drug-release profiles from loaded samples were investigated in PBS at pH = 7.4 and human plasma. 相似文献
105.
Thabuis C Tissot-Favre D Bezelgues JB Martin JC Cruz-Hernandez C Dionisi F Destaillats F 《Journal of chromatography. A》2008,1202(2):216-219
Oleoylethanolamide (OEA) is known to potentially have beneficial biological effects on weight management by controlling food intake and activating lipid catabolism. In biological fluids, OEA and other endogenously biosynthesized fatty acid ethanolamides are usually analyzed by liquid chromatography-mass spectrometry (LC-MS). The present study provides analytical method to routinely assess the quality of OEA prepared for biological studies by gas-liquid chromatography (GLC). The preparation of OEA for biomedical studies can be performed by N-acylation of oleic acid/esters or using oleoyl chloride. In the present study, OEA was prepared by transamidation of triolein. The analysis of the synthesized OEA has been performed by gas-liquid chromatography of its trimethylsilyl ether (TMS) derivatives. Free OEA cannot be analyzed as such because dehydration of the ethanolamide moiety promptly happens in the GLC injection. This thermal degradation reaction gives rise to the formation of an oxazoline derivative. The TMS moiety prevents the reaction, and the structure of the formed derivative was assessed by mass spectrometry. We show here that OEA prepared for biological studies can be routinely analyzed by GLC after TMS derivative preparation. 相似文献
106.
Mirko De Rosso Annarita Panighel Daniele Migliaro Tyrone Possamai Fabiola De Marchi Riccardo Velasco Riccardo Flamini 《Journal of mass spectrometry : JMS》2023,58(10):e4961
A breeding program to produce new grape varieties tolerant to main vine fungal pathogens (Plasmopara viticola and Erysiphe necator) is carrying out by crossing Vitis vinifera cv. “Glera” with resistant genotypes such as “Solaris,” “Bronner,” and “Kunleany.” Firstly, resistance gene-based markers analyses allowed the identification of five genotypes, which have inherited the resistance loci against mildews. To select those that also inherited the phenotype as close as possible to ‘Glera’ suitable to be introduced in the Prosecco wine production protocols, the grape glycosidic derivatives were studied by UHPLC/QTOF mass spectrometry. Targeted identification of the metabolites was performed using a database expressly constructed by including the glycosidic volatile precursors previously identified in grape and wine. A total of 77 glycosidic derivatives including many aroma precursors and some variety markers, were identified. Original resistant genotypes had distinct metabolomic profiles and different to ‘Glera’, while the crossings showed varying similarity degrees to V. vinifera parent. Findings demonstrated the Glera × Bronner and Glera × Solaris crossings are more suitable to produce high-sustainable Prosecco wines. Coupling of glycosidic volatile precursors profiling to multivariate statistical analysis was effective for phenotypic characterization of grapes and to evaluate their enological potential. 相似文献
107.
Fabiola Arevalo Antonella Cid Jorge Moya 《The European Physical Journal C - Particles and Fields》2017,77(8):565
In this work we study linear and nonlinear cosmological interactions, which depend on dark matter and dark energy densities in the framework of general relativity. By using the Akaike information criterion (AIC) and the bayesian information criterion (BIC) with data from SnIa (Union 2.1 and binned JLA), \(\mathrm{H(z)}\), BAO and CMB we compare the interacting models among themselves and analyze whether more complex interacting models are favored by these criteria. In this context, we find some suitable interactions that alleviate the coincidence problem. 相似文献
108.
Lillian G. Ramírez-Palma Adrin Espinoza-Guilln Fabiola Nieto-Camacho Alexis E. Lpez-Guerra Virginia Gmez-Vidales Fernando Corts-Guzmn Lena Ruiz-Azuara 《Molecules (Basel, Switzerland)》2021,26(19)
A strategy to improve the cancer therapies involves agents that cause the depletion of the endogenous antioxidant glutathione (GSH), increasing its efflux out of cells and inducing apoptosis in tumoral cells due to the presence of reactive oxygen species. It has been shown that Casiopeina copper complexes caused a dramatic intracellular GSH drop, forming disulfide bonds and reducing CuII to CuI. Herein, through the determination of the [CuII]–SH bond before reduction, we present evidence of the adduct between cysteine and one Casiopeina as an intermediate in the cystine formation and as a model to understand the anticancer activity of copper complexes. Evidence of such an intermediate has never been presented before. 相似文献
109.
Alan-Misael Alonso Oscar Kevin Reyes-Maldonado Ana María Puebla-Prez Martha Patricia Gallegos Arreola Sandra Fabiola Velasco-Ramírez Victor Zúiga-Mayo Rosa E. Snchez-Fernndez Jorge-Ivn Delgado-Saucedo Gilberto Velzquez-Jurez 《Molecules (Basel, Switzerland)》2022,27(11)
In recent years, the increase in antibiotic resistance demands searching for new compounds with antimicrobial activity. Phytochemicals found in plants offer an alternative to this problem. The genus Pelargonium contains several species; some have commercial use in traditional medicine such as P. sinoides, and others such as P. peltatum are little studied but have promising potential for various applications such as phytopharmaceuticals. In this work, we characterized the freeze-dried extracts (FDEs) of five tissues (root, stem, leaf, and two types of flowers) and the ethyl acetate fractions from leaf (Lf-EtOAc) and flower (Fwr-EtOAc) of P. peltatum through the analysis by thin-layer chromatography (T.L.C.), gas chromatography coupled to mass spectrometry (GC-MS), phytochemicals quantification, antioxidant capacity, and antimicrobial activity. After the first round of analysis, it was observed that the FDE-Leaf and FDE-Flower showed higher antioxidant and antimicrobial activities compared to the other FDEs, for which FDE-Leaf and FDE-Flower were fractionated and analyzed in a second round. The antioxidant activity determined by ABTS showed that Lf-EtOAc and Fwr-EtOAc had the lowest IC50 values with 27.15 ± 1.04 and 28.11 ± 1.3 µg/mL, respectively. The content of total polyphenols was 264.57 ± 7.73 for Lf-EtOAc and 105.39 ± 4.04 mg G.A./g FDE for Fwr-EtOAc. Regarding the content of flavonoid, Lf-EtOAc and Fw-EtOAc had the highest concentration with 34.4 ± 1.06 and 29.45 ± 1.09 mg Q.E./g FDE. In addition, the minimum inhibitory concentration (M.I.C.) of antimicrobial activity was evaluated: Lf-EtOAc and Fwr-EtOAc were effective at 31.2 µg/mL for Staphylococcus aureus and 62.5 µg/mL for Salmonella enterica, while for the Enterococcus feacalis strain, Fwr-EtOAc presented 31.2 µg/mL of M.I.C. According to the GC-MS analysis, the main compounds were 1,2,3-Benzenetriol (Pyrogallol), with 77.38% of relative abundance in the Lf-EtOAc and 71.24% in the Fwr-EtOAc, followed by ethyl gallate (13.10%) in the Fwr-EtOAc and (Z)-9-Octadecenamide (13.63% and 6.75%) in both Lf-EtOAc and Fwr-EtOAc, respectively. 相似文献
110.
Cesar Castillo-Quevedo Carlos Emiliano Buelna-Garcia Edgar Paredes-Sotelo Eduardo Robles-Chaparro Edgar Zamora-Gonzalez Martha Fabiola Martin-del-Campo-Solis Jesus Manuel Quiroz-Castillo Teresa del-Castillo-Castro Gerardo Martínez-Guajardo Aned de-Leon-Flores Manuel Cortez-Valadez Filiberto Ortiz-Chi Tulio Gaxiola Santos Jesus Castillo Alejandro Vsquez-Espinal Sudip Pan Jose Luis Cabellos 《Molecules (Basel, Switzerland)》2021,26(18)
In this study, we report the lowest energy structure of bare Cu13 nanoclusters as a pair of enantiomers at room temperature. Moreover, we compute the enantiomerization energy for the interconversion from minus to plus structures in the chiral putative global minimum for temperatures ranging from 20 to 1300 K. Additionally, employing nanothermodynamics, we compute the probabilities of occurrence for each particular isomer as a function of temperature. To achieve that, we explore the free energy surface of the Cu13 cluster, employing a genetic algorithm coupled with density functional theory. Moreover, we discuss the energetic ordering of isomers computed with various density functionals. Based on the computed thermal population, our results show that the chiral putative global minimum strongly dominates at room temperature. 相似文献