全文获取类型
收费全文 | 209篇 |
免费 | 8篇 |
专业分类
化学 | 182篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 10篇 |
物理学 | 21篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2016年 | 14篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 18篇 |
2012年 | 16篇 |
2011年 | 18篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 13篇 |
2006年 | 14篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有217条查询结果,搜索用时 11 毫秒
61.
Dr. Fabiana E. García Prof. Marta I. Litter Prof. Isabella Natali Sora 《ChemistryOpen》2021,10(8):790-797
The catalytic performance of a perovskite-type lanthanum ferrite LaFeO3 to remove arsenic from water has been investigates for the first time. LaFeO3 was prepared by citrate auto-combustion of dry gel obtained from a solution of the corresponding nitrates poured into citric acid solution. Kinetic studies were performed in the dark with As(V) and in the dark and under UV-C irradiation at pH 6–7 with As(III) (both 1 mg L−1), and As : Fe molar ratios (MR) of 1 : 10 and 1 : 100 using the LaFeO3 catalyst. As(V) was removed from solution after 60 min in the dark in 7 % and in 47 % for MR=1 : 10 and MR=1 : 100, respectively, indicating the importance of the amount of the iron material on the removal. Oxidation of As(III) in the dark was negligible after 60 min in contact with the solid sample, but complete removal of As(III) was observed within 60 min of irradiation at 254 nm, due to As(III) photooxidation to As(V) and to As(III) sorption to a minor extent. Morphological and microstructural studies of the catalyst complement the catalytic testing. This work demonstrates that LaFeO3 can be used for the removal of As(III) from highly arsenic contaminated water. 相似文献
62.
[reaction: see text] A new approach for the synthesis of (+/-)-indatraline, which is a 3-phenyl-1-indanamine that displays several biological activities, is described. The strategy features as the key step a diastereoselective ring contraction of a 1,2-dihydronaphthalene promoted by PhI(OTs)OH, to construct the indan ring system. The oxidative rearrangement of other 1,2-dihydronaphthalenes was also investigated, generalizing this method to obtain indans. 相似文献
63.
Ostacolo L Russo P De Rosa G La Rotonda MI Maglio G Nese G Spagnuolo G Rengo S Oliva A Quaglia F 《Macromolecular bioscience》2008,8(7):682-689
The production of PEEA microspheres with potential as carriers for protein oral delivery is described. PEEAs with different hydrophilicity were synthesized and characterized. Experiments showed that an increase in copolymer hydrophilicity gave particles less prone to cell interaction. BSA release profiles from PEEA microspheres demonstrated that an increase in polymer hydrophilicity was useful in limiting protein burst and modulating drug delivery rate by increasing PEEA degradability. These results show that fine-tuning of the hydrophilic/hydrophobic properties of PCL is essential for the formulation protein-loaded microspheres with specific properties. 相似文献
64.
Ishiruji FH Nunes FS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,68(1):94-98
Molecular modeling and a detailed spectroscopic characterization of the macrocyclic complex [Co(meso)(CN)(2)](+) (meso = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) is herein presented. Structural, electronic and vibrational features are discussed and assignments were proposed on the basis of semi-empirical (molecular mechanics (MM+), ZINDO/S and PM3) quantum-mechanics calculations. The energy and the composition of the molecular orbitals of the complex were calculated and a quantitative diagram was constructed. The simulated UV-vis spectrum exhibited a reasonably good accordance with the experimental one and fully assignments of seven bands were made. An optimized configuration of the complex showed a strong cobalt-cyanide axial bond in agreement with the major contribution of the cyanide to the composition of the molecular orbitals in contrast to a discrete participation of the macrocyclic meso to the ground state of the complex. 相似文献
65.
Mancilha FS Barloy L Rodembusch FS Dupont J Pfeffer M 《Dalton transactions (Cambridge, England : 2003)》2011,40(40):10535-10544
The cyclopalladation of the 4-aryl-2,1,3-benzothiadiazoles 1a-c with palladium acetate in acetic acid afforded the novel dimeric complexes 2a-c in good yields. These were then converted into the monomeric pyridine-, chloro-coordinated cyclometallated complexes 3a-c through reaction with lithium chloride in acetone and then pyridine in dichloromethane. All complexes were fully characterized by means of NMR, IR and elemental analysis. The X-ray structure of complex 2c revealed that it presents transoid geometry, whereas the X-ray structure of 3c shows that the pyridine ligand and the thiazole ring are mutually trans. Photophysical properties were investigated by means of UV-Vis absorption and fluorescence emission in solution. Solid-state diffuse reflectance UV-Vis spectra (DRUV) were also applied in order to better characterize the complexes photophysics in the solid state. All complexes present intense absorption at around 300 nm (λ(1)) via(1)LC transitions located in BTD ligands, and additional low energy absorption bands, higher than 450 nm (λ(2)) of (1)MLCT character. The complexes are fluorescent in solution at room temperature, where two emission bands could be observed, a high energy band (excitation @ λ(1)) ascribed to the ligand emission and an additional red shifted low intense band (excitation @ λ(2)) due to the complex emission. 相似文献
66.
Mazzaglia A Valerio A Micali N Villari V Quaglia F Castriciano MA Scolaro LM Giuffrè M Siracusano G Sciortino MT 《Chemical communications (Cambridge, England)》2011,47(32):9140-9142
An emitting nanoassembly composed of a novel amphiphilic cyclodextrin functionalised with a covalently appended fluorophore and an anionic porphyrin internalizes effectively in tumor cells, allowing simultaneously the detection of carrier and photosensitiser. 相似文献
67.
Valentina Lo Giudice Immacolata Faraone Maria Roberta Bruno Maria Ponticelli Fabiana Labanca Donatella Bisaccia Carmine Massarelli Luigi Milella Luigi Todaro 《Molecules (Basel, Switzerland)》2021,26(16)
The need to produce an ever-increasing quantity of material products and food resulting from the planet globalization process has contributed to the spread of modern agriculture based on a linear production resulting in the generation of tons of waste. This huge amount of waste is generally accumulated in landfills, causing different environmental problems. Hence, researchers moved on to study the processes used to recover agro-industrial by-products within a circular and sustainable bio-economy concept. A systematic quest on Scopus and PubMed databases was performed to identify the data available to date on recycling agro-industrial by-products of Olea europaea L. This systematic review summarizes the knowledge regarding the use of olive trees by-products for producing animal feed, biocomposites, bioethanol, cellulose pulp, activated carbon, and as a fuel source for energy production. Furthermore, the data regarding the potential biological activity of extracts from olive roots, wood, bark, and pruning were analyzed. Olive trees by-products are, indeed, rich in molecules with antioxidant, antimicrobial, cardioprotective, and anticancer activity, representing a promising candidate for treat several human diseases. 相似文献
68.
Isabeau?Birindelli Giulio?Galise Fabiana?LeoniEmail author Filomena?Pacella 《Calculus of Variations and Partial Differential Equations》2018,57(6):158
We study the asymptotic behavior of positive solutions of fully nonlinear elliptic equations in a ball, as the exponent of the power nonlinearity approaches a critical value. We show that solutions concentrate and blow up at the center of the ball, while a suitable associated energy remains invariant. 相似文献
69.
Clayane Carvalho dos Santos Marcelo de Assis Thales Rafael Machado Paula Fabiana dos Santos Pereira Gladys Minguez‐Vega Eloisa Cordoncillo Hector Beltran‐Mir Carlos Doate‐Buendía Juan Andrs Elson Longo 《Particle & Particle Systems Characterization》2019,36(6)
In this work, for the first time, the instantaneous nucleation and growth processes of Ag nanoparticles on Ag3PO4 mediated by femtosecond laser pulses are reported and analyzed. The investigated samples are pure Ag3PO4 sample, electron‐irradiated Ag3PO4 sample, and laser‐irradiated sample. Complete characterization of the samples is performed using X‐ray diffraction (XRD), Rietveld refinements, field emission scanning electron microscopy, and energy dispersive spectroscopy (EDS). XRD confirms that the irradiated surface layer remains crystalline, and according to EDS analysis, the surface particles are composed primarily of Ag nanoparticles. This method not only offers a one‐step route to synthesize Ag nanoparticles using laser‐assisted irradiation with particle size control, but also reports a complex process involving the formation and subsequent growth of Ag nanoparticles through an unexpected additive‐free in situ fabrication process. 相似文献
70.
Patrícia F. Lainetti Antonio F. Leis-Filho Priscila E. Kobayashi Laíza S. de Camargo Renee Laufer-Amorim Carlos E. Fonseca-Alves Fabiana F. Souza 《Molecules (Basel, Switzerland)》2021,26(5)
Rapamycin is an antifungal drug with antitumor activity and acts inhibiting the mTOR complex. Due to drug antitumor potential, the aim of this study was to evaluate its effect on a preclinical model of primary mammary gland tumors and their metastases from female dogs. Four cell lines from our cell bank, two from primary canine mammary tumors (UNESP-CM1, UNESP-CM60) and two metastases (UNESP-MM1, and UNESP-MM4) were cultured in vitro and investigated for rapamycin IC50. Then, cell lines were treated with rapamycin IC50 dose and mRNA and protein were extracted in treated and non-treated cells to perform AKT, mTOR, PTEN and 4EBP1 gene expression and global proteomics by mass spectrometry. MTT assay demonstrated rapamycin IC50 dose for all different tumor cells between 2 and 10 μM. RT-qPCR from cultured cells, control versus treated group and primary tumor cells versus metastatic tumor cells, did not shown statistical differences. In proteomics were found 273 proteins in all groups, and after data normalization 49 and 92 proteins were used for statistical analysis for comparisons between control versus rapamycin treatment groups, and metastasis versus primary tumor versus metastasis rapamycin versus primary tumor rapamycin, respectively. Considering the two statistical analysis, four proteins, phosphoglycerate mutase, malate dehydrogenase, l-lactate dehydrogenase and nucleolin were found in decreased abundance in the rapamycin group and they are related with cellular metabolic processes and enhanced tumor malignant behavior. Two proteins, dihydrolipoamide dehydrogenase and superoxide dismutase, also related with metabolic processes, were found in higher abundance in rapamycin group and are associated with apoptosis. The results suggested that rapamycin was able to inhibit cell growth of mammary gland tumor and metastatic tumors cells in vitro, however, concentrations needed to reach the IC50 were higher when compared to other studies. 相似文献