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排序方式: 共有176条查询结果,搜索用时 15 毫秒
1.
Csányi G Cifuentes-Pagano E Al Ghouleh I Ranayhossaini DJ Egaña L Lopes LR Jackson HM Kelley EE Pagano PJ 《Free radical biology & medicine》2011,51(6):1116-1125
In recent years, reactive oxygen species (ROS) derived from the vascular isoforms of NADPH oxidase, Nox1, Nox2, and Nox4, have been implicated in many cardiovascular pathologies. As a result, the selective inhibition of these isoforms is an area of intense current investigation. In this study, we postulated that Nox2ds, a peptidic inhibitor that mimics a sequence in the cytosolic B-loop of Nox2, would inhibit ROS production by the Nox2-, but not the Nox1- and Nox4-oxidase systems. To test our hypothesis, the inhibitory activity of Nox2ds was assessed in cell-free assays using reconstituted systems expressing the Nox2-, canonical or hybrid Nox1-, or Nox4-oxidase. Our findings demonstrate that Nox2ds, but not its scrambled control, potently inhibited superoxide (O2•−) production in the Nox2 cell-free system, as assessed by the cytochrome c assay. Electron paramagnetic resonance confirmed that Nox2ds inhibits O2•− production by Nox2 oxidase. In contrast, Nox2ds did not inhibit ROS production by either Nox1- or Nox4-oxidase. These findings demonstrate that Nox2ds is a selective inhibitor of Nox2-oxidase and support its utility to elucidate the role of Nox2 in organ pathophysiology and its potential as a therapeutic agent. 相似文献
2.
Nathaniel Edward Bennett Saidu Imad Abu Asali Brigitte Czepukojc Berthold Seitz Claus Jacob Mathias Montenarh 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Diallyl mono- and polysulfanes from garlic are known to induce an adaptive cell response and the formation of antioxidants in cancer cells. In the case of a severe ER stress and a failure in the response, cancer cells eventually go into apoptosis. Only little is known about the response of normal cells upon treatment.Methods
Normal ARPE-19 cells were treated with diallyl tetrasulfide to study their cellular response and the results were compared with those of HCT116 cancer cells. Cell viability was checked by an MTT assay and cytofluorimetry. The formation of superoxide radicals, H2O2 and thiols were determined and proteins involved in the ER stress response were also detected by Western blot analysis.Results
We found that diallyl tetrasulfide induced reactive oxygen species (ROS) in normal cells similar to cancer cells in a time (0 to 60 min) and dose dependent manner (0 to 50 μM). The level of heme oxigenase-1 (HO-1) was up-regulated in both cell types. Initially, we found a decrease in the total thiol level in both cell types but in contrast to cancer cells, normal cells recovered from the decrease in the total thiol concentration within 60 min of treatment.Conclusions
The recovery of the thiol concentration in normal cells treated with diallyl tetrasulfide seems to be responsible for the failure to induce the ER stress signalling pathway and finally apoptosis in normal cells.General Significance
The difference in the recovery of the thiol status might be an explanation for the anti-carcinogenic effects of garlic compounds. 相似文献3.
Kanaze FI Kokkalou E Georgarakis M Niopas I 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,801(2):363-367
Naringenin and hesperetin, the aglycones of the flavanone glucosides naringin and hesperidin occur naturally in citrus fruits. They exert a variety of pharmacological effects such as antioxidant, blood lipid-lowering, anticarcinogenic and inhibit selected cytochrome P-450 enzymes resulting in drug interactions. A specific, sensitive, precise, and accurate solid-phase extraction high-performance liquid chromatographic (HPLC) assay for the simultaneous determination of naringenin and hesperetin in human plasma was developed and validated. After addition of 7-ethoxycoumarin as internal standard, plasma samples were incubated with beta-glucuronidase/sulphatase, and the analytes were isolated from plasma by solid-phase extraction using C(18) cartridges and separated on a C(8) reversed phase column with methanol/water/acetic acid (40:58:2, v/v/v) as the eluent at 45 degrees C. The method was linear in the 10-300 ng/ml concentration range for both naringenin and hesperetin (r>0.999). Recovery for naringenin, hesperetin and internal standard was greater than 76.7%. Intra- and inter-day precision for naringenin ranged from 1.4 to 4.2% and from 1.9 to 5.2%, respectively, and for hesperetin ranged from 1.3 to 4.1% and from 1.7 to 5.1%, respectively. Accuracy was better than 91.5 and 91.3% for naringenin and hesperetin, respectively. 相似文献
4.
Mid-infrared spectra of freeze-dried sucrose and lactose systems were acquired over a range of temperatures (30-200 degrees C) and water contents (0-6.3%). Starting from the glassy state, the experimental conditions were selected to cover the main thermal transitions: the glass-rubber transition, the crystallisation and, for some samples, the subsequent melting. The FTIR spectra were very sensitive to the physical state. While subtle but systematic spectral differences between the glassy and rubbery states were detectable throughout the spectrum, a very pronounced increase in spectral resolution was observed as crystallisation occurred and was followed by the expected spectral broadening during melting. The temperatures at which these changes occurred were in satisfactory agreement with the transition temperatures measured by differential scanning calorimetry (DSC). The increase in molecular mobility as a result of increasing temperature or plasticisation by water led to a significant shift of the O-H stretching band to higher wavenumbers indicating a weakening of hydrogen bonding. This shift reached a maximum as the DSC measured crystallisation temperature range was approached. As expected, the crystallisation led to a highly effective hydrogen bonding network. This was more significant for lactose than for sucrose. No significant step change in hydrogen bonding was observed at Tg. As anticipated, the temperature at which these transitions occurred decreased with increasing water content but overlapped when observed in the context of the shifted temperature (T-Tg). 相似文献
5.
Aims
The present study is designed to evaluate the in vitro and in vivo bactericidal and immunomodulating activities of hesperidin (HES) and ellagic acid (EA) against Aeromonas hydrophila. A hydrophila, an uncommon human pathogen, can cause invasive infections in immunocompromised individuals and common clinical presentations in acute gastrointestinal illness, soft-tissue infections and sepsis. The antimicrobial activities of medicinal plants against A. hydrophila have received only cursory attention.Methods
We examined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values in vitro. Moreover, the effects of HES and EA against bacterial colonization were studied in vivo. Also, humoral immune response was tested against A. hydrophila-LPS or A. hydrophila-ECP antigen preparations and the intestinal histopathological alterations were studied.Results
Data revealed that the treatments with HES and EA each had antimicrobial activities against A. hydrophila. Both HES and EA treatments significantly increased anti-LPS IgM levels and reduced anti-LPS and anti-ECP IgA levels to their normal values in comparison to the infected group, which recorded significantly elevated levels two week post-infection. In conclusion, the present data suggest that HES and EA have antimicrobial and immunomodulating activities against murine A. hydrophila infections.Significant
These data warrant clinical studies to delineate HES and EA roles in human infectious diseases. 相似文献6.
Xuefei Tan Richland W. Tester Gregory R. Luedtke Sarvajit Chakravarty Babu J. Mavunkel John J. Perumattam Qing Lu Imad Nashashibi Joon Jung Jie Hu Albert Liclican Ramona Almirez Jocelyn Tabora Vinh Tran Maureen Laney Daniel E. Levy Sundeep Dugar 《Bioorganic & medicinal chemistry letters》2010,20(3):828-831
Derivatives of the 4-fluorobenzyl dimethylpiperazine-indole class of p38α MAP kinase inhibitors are described. Biological evaluation of these compounds focused on maintaining activity while improving pharmacokinetic (PK) properties. Improved properties were observed for structures bearing substitutions on the benzylic methylene. 相似文献
7.
Hitomi Kumagai William MacNaughtan Imad A. Farhat John R. Mitchell 《Carbohydrate polymers》2002,48(4):341-349
The influence of less than 1% of κ-carrageenan on the mobility of glucose syrup was studied in the context of the glass–rubber transition using proton NMR relaxometry. Glass-transition temperatures, (Tg) were measured by differential scanning calorimetry (DSC) on glucose syrup samples containing 0 or 0.9% κ-carrageenan, between 0 and 1.4% KCl, and at water contents from 3.5 to 16% (wwb). Potassium chloride was added to vary the extent of gelation of the carrageenan in order to assess the effect of the biopolymer network on molecular mobility.
Contrary to the reported increase of the rheologically determined glass-transition temperature, in the presence of gelling agents, the addition of 0.9% κ-carrageenan to glucose syrup with and without KCl, had no effect on the DSC measured Tg. In addition, there was no effect on molecular mobility in the glassy region. The presence of carrageenan only significantly affected the mobile part of the NMR free induction decay at relatively high temperatures. 相似文献
8.
Imad Mennai Esma Lamera Nabila Slougui Brahim Benaicha Salim Gasmi Zakaria Samai Naima Rahmouni Chawki Bensouici Diana C. G. A. Pinto 《化学与生物多样性》2021,18(9):e2100278
This work aimed to investigate, for the first time, the chemical composition, antioxidant, antiparasitic, cytotoxicity, and antimicrobial activities of the aromatic plant Limonium oleifolium Mill. essential oil (EO) and organic extracts. L. oleifolium aerial parts essential oil was analyzed by GC-FID and GC-MS, and 46 constituents representing 98.25±1.12 % of the oil were identified. γ-Muurolene (10.81±0.07 %), cis-caryophyllene (7.71±0.06 %), o-cymene (7.07±0.01 %) and α-copaene (5.02±0.05 %) were the essential oil main compounds. The antioxidant activity of L. oleifolium EO and organic extracts (MeOH, CHCl3, AcOEt, BuOH) was explored using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS, β-carotene/linoleic acid, cupric reducing antioxidant capacity (CUPRAC), and ferric reducing power assays. The results showed that L. oleifolium EO exhibit antioxidant capacity (IC50=17.40±1.32 μg/mL for DPPH assay, IC50=29.82±1.08 μg/mL for β-carotene assay, IC50=25.23±1.01 μg/mL for ABTS assay, IC50=9.11±0.08 μg/mL for CUPRAC assay and IC50=19.41±2.06 mg/mL for reducing power assay). Additionally, the EO showed significant activity against trophozoite form of Acanthamoeba castellanii (IC50=7.48±0.41 μg/mL) and promastigote form of Leishmania amazonensis (IC50=19.36±1.06 μg/mL) and low cytotoxicity on murine macrophages (LC50 90.23±1.09 μg/mL), as well as good antimicrobial activity against Staphylococcus aureus, Escherichia coli, Klebsiella oxytoca, and Pseudomonas aeruginosa. These results suggest that L. oleifolium essential oil is a valuable source of bioactive compounds presenting antioxidant, antiparasitic, and antimicrobial activities. Furthermore, it is considered nontoxic. 相似文献
9.
Jeppe Reitan Andersen Imad Zein Gerhard Wenzel Birte Darnhofer Joachim Eder Milena Ouzunova Thomas Lübberstedt 《BMC plant biology》2008,8(1):2