全文获取类型
收费全文 | 297篇 |
免费 | 9篇 |
专业分类
化学 | 265篇 |
力学 | 5篇 |
数学 | 10篇 |
物理学 | 26篇 |
出版年
2024年 | 1篇 |
2022年 | 13篇 |
2021年 | 16篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 15篇 |
2017年 | 6篇 |
2016年 | 16篇 |
2015年 | 10篇 |
2014年 | 7篇 |
2013年 | 22篇 |
2012年 | 18篇 |
2011年 | 16篇 |
2010年 | 16篇 |
2009年 | 14篇 |
2008年 | 16篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 19篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 1篇 |
排序方式: 共有306条查询结果,搜索用时 0 毫秒
81.
Anna A. Skuredina Tatiana Yu. Kopnova Anastasia S. Tychinina Sergey A. Golyshev Irina M. Le-Deygen Natalya G. Belogurova Elena V. Kudryashova 《Molecules (Basel, Switzerland)》2022,27(22)
The new method of antibacterial-drug-activity investigation in vitro is proposed as a powerful strategy for understanding how carriers affect drug action during long periods (7 days). In this paper, we observed fluoroquinolone moxifloxacin (MF) antibacterial-efficiency in non-covalent complexes, with the sulfobutyl ether derivative of β-cyclodextrin (SCD) and its polymer (SCDpol). We conducted in vitro studies on two Escherichia coli strains that differed in surface morphology. It was found that MF loses its antibacterial action after 3–4 days in liquid media, whereas the inclusion of the drug in SCD led to the increase of MF antibacterial activity by up to 1.4 times within 1–5 days of the experiment. In the case of MF-SCDpol, we observed a 12-fold increase in the MF action, and a tendency to prolonged antibacterial activity. We visualized this phenomenon (the state of bacteria, cell membrane, and surface morphology) during MF and MF-carrier exposure by TEM. SCD and SCDpol did not change the drug’s mechanism of action. Particle adsorption on cells was the crucial factor for determining the observed effects. The proteinaceous fimbriae on the bacteria surface gave a 2-fold increase of the drug carrier adsorption, hence the strains with fimbriae are more preferable for the proposed treatment. Furthermore, the approach to visualize the CD polymer adsorption on bacteria via TEM is suggested. We hope that the proposed comprehensive method will be useful for the studies of drug-delivery systems to uncover long-term antibacterial action. 相似文献
82.
Natalya Shekhovtsova Tatyana Glyzina Sergey Romanenko Nina Kolpakova 《Journal of Solid State Electrochemistry》2012,16(7):2419-2423
The method of partial anodic peak resolution is applied to complex voltammograms. The estimation of the composition of the intermetallic Bi–Pt compounds electrolytically deposited is carried out by a resolution of the components of the voltammograms. It is shown that nonequilibrium conditions take place in electrolytic Bi–Pt deposit when three intermetallic compounds such as: Pt2Bi3, PtBi2, PtBi, and phase of pure Bi exist simultaneously on the electrode. 相似文献
83.
84.
Khakina EA Troyanov SI Peregudov AS Soulimenkov IV Polyakova NV Troshin PA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(43):12947-12955
We report the first reaction of trannulenes involving their thermal isomerization to a new class of compounds termed "triumphenes". The thermodynamically controlled conversion of trannulenes into triumphenes is accompanied by an unprecedented migration of three organic addends from one hemisphere of the fullerene cage to another. The reaction products, bearing aliphatic substituents, might find applications in materials science as strong electron acceptors due to the presence of fifteen electron-withdrawing fluorine atoms in their molecular framework. It was revealed that the isomerization of trannulenes can be affected by the presence of unsaturated compounds in the reaction mixture. Heating of trannulenes C(60)F(15)R(3) with C(60), C(70), anthracene, or pentacene at reflux in 1,2-dichlorobenzene yields fluorinated derivatives C(60)F(14)R(2)A, which possess a fused cyclic addend A. The products of this reaction have "triumphene-type" addition patterns and seem to be formed through an unprecedented sequence of elimination, addition, and isomerization steps. The molecular structure of a representative triumphene was proven unambiguously by X-ray single-crystal diffraction analysis and by NMR spectroscopy. The reactions revealed here open up numerous opportunities for chemical derivatization of fluorinated fullerenes. This method promises to provide a new path towards valuable photoactive materials and a new generation of fullerene-based compounds that are suitable for biomedical applications. 相似文献
85.
Immunosuppressive effects of the minor component of the terrestrial solar spectrum, UV radiation, have been substantiated over the past several years. This raises the question of what influence the dominant part of the solar spectrum--visible and IR light-would have on the human immune system. In the present randomized, placebo-controlled double-blind study a small area of the body surface of volunteers was irradiated with polychromatic light (480-3400 nm), simulating the significant part of the terrestial sunlight irradiance spectrum and its power density. An average 2.5-fold to three-fold increase in spontaneous and phytohemagglutinin-induced DNA synthesis in peripheral blood lymphocytes (Lym) was revealed at 0.5-24 h after irradiation at a therapeutic dose (12 J/cm(2)) in subjects with low preirradiation levels of both processes. The in vivo findings were echoed in parallel in vitro experiments, when blood drawn from the same subjects was directly irradiated (2.4 J/cm(2)), or when the irradiated blood was mixed 1:10 with nonirradiated autologous blood to model events in the circulation following transcutaneous blood photomodification. Our data suggest that exposure of the human body to polychromatic visible + IR light may photomodify blood in the dermal vasculature of the irradiated area to lead to an immediate transfer of the light-induced effects to Lym of the entire circulating blood, which can result in modulation of Lym functional state at the systemic level. 相似文献
86.
87.
Ivanets Andrei Milyutin Vitaliy Shashkova Irina Kitikova Natalja Nekrasova Natalya Radkevich Artsiom 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(3):1115-1123
Journal of Radioanalytical and Nuclear Chemistry - In this paper, we studied the features of stable and radioactive Cs(I), Sr(II) and Co(II) ions sorption on Ti–Ca–Mg phosphates. The... 相似文献
88.
Pedro Morales-García Evelyn Y. Calvillo-Muoz Irina V. Lijanova Natalya V. Likhanova Octavio Olivares-Xometl Paulina Arellanes-Lozada 《Molecules (Basel, Switzerland)》2021,26(18)
The use of new synthesized ammonium-based ionic liquids was explored as an alternative to the current process implemented in the betanin extraction from red beet juice, resulting in high yields: 70% and 82%. Betanin is a vegetal pigment that has been applied to a large variety of products in the food industry, which is important, for it can work as a substitute for the red synthetic dyes used nowadays. Additionally, the use of the kosmotropic salt sodium acetate was explored in order to separate the complex formed by the ionic liquid and pigment of interest in a process that combined two techniques: ATPS (aqueous two-phase system) and SOES (salting-out extraction system). The results reveal that the studied techniques could work as a novel process for the extraction of betanin from red beet juice employing ionic liquids, which have not been tested for this purpose in other research. 相似文献
89.
90.