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排序方式: 共有344条查询结果,搜索用时 31 毫秒
61.
Sevan R. Oungoulian Kristin E. Hehir Kaicen Zhu Callen E. Willis Anca G. Marinescu Natasha Merali Christopher S. Ahmad Clark T. Hung Gerard A. Ateshian 《Journal of biomechanics》2014
This study examined functional properties and biocompatibility of glutaraldehyde-fixed bovine articular cartilage over several weeks of incubation at body temperature to investigate its potential use as a resurfacing material in joint arthroplasty. In the first experiment, treated cartilage disks were fixed using 0.02, 0.20 and 0.60% glutaraldehyde for 24 h then incubated, along with an untreated control group, in saline for up to 28 d at 37 °C. Both the equilibrium compressive and tensile moduli increased nearly twofold in treated samples compared to day 0 control, and remained at that level from day 1 to 28; the equilibrium friction coefficient against glass rose nearly twofold immediately after fixation (day 1) but returned to control values after day 7. Live explants co-cultured with fixed explants showed no quantitative difference in cell viability over 28 d. In general, no significant differences were observed between 0.20 and 0.60% groups, so 0.20% was deemed sufficient for complete fixation. In the second experiment, cartilage-on-cartilage frictional measurements were performed under a migrating contact configuration. In the treated group, one explant was fixed using 0.20% glutaraldehyde while the apposing explant was left untreated; in the control group both explants were left untreated. From day 1 to 28, the treated group exhibited either no significant difference or slightly lower friction coefficient than the untreated group. These results suggest that a properly titrated glutaraldehyde treatment can reproduce the desired functional properties of native articular cartilage and maintain these properties for at least 28 d at body temperature. 相似文献
62.
It has previously been established that, in threatening situations, animals use alarm pheromones to communicate danger. There is emerging evidence of analogous chemosensory “stress” cues in humans. For this study, we collected alarm and exercise sweat from “donors,” extracted it, pooled it and presented it to 16 unrelated “detector” subjects undergoing fMRI. The fMRI protocol consisted of four stimulus runs, with each combination of stimulus condition and donor gender represented four times. Because olfactory stimuli do not follow the canonical hemodynamic response, we used a model-free approach. We performed minimal preprocessing and worked directly with block-average time series and step-function estimates. We found that, while male stress sweat produced a comparably strong emotional response in both detector genders, female stress sweat produced a markedly stronger arousal in female than in male detectors. Our statistical tests pinpointed this gender-specificity to the right amygdala (strongest in the superficial nuclei). When comparing the olfactory bulb responses to the corresponding stimuli, we found no significant differences between male and female detectors. These imaging results complement existing behavioral evidence, by identifying whether gender differences in response to alarm chemosignals are initiated at the perceptual versus emotional level. Since we found no significant differences in the olfactory bulb (primary processing site for chemosensory signals in mammals), we infer that the specificity in responding to female fear is likely based on processing meaning, rather than strength, of chemosensory cues from each gender. 相似文献
63.
Rhinolophus mehelyi (Mehely's horseshoe bat) is a vulnerable species with an increasingly fragmented distribution. In Romania, populations of
R. mehelyi have experienced a dramatic decline over the past 50 years, and the current population size is estimated at only 100 adult
individuals inhabiting almost exclusively the Limanu cave. In the present study, we investigated the genetic consequences
of population decline for the viability of the remaining population of R. mehelyi in Romania. We sequenced and analyzed a 359-bp fragment of the mitochondrial control region from the only known Romanian
population and compared it with two geographically close colonies from Bulgaria. A single haplotype was found in the Romanian
population compared to 10 in the Bulgarian population, suggesting genetic isolation. 相似文献
64.
SunCHem: an integrated process for the hydrothermal production of methane from microalgae and CO2 mitigation 总被引:1,自引:0,他引:1
Anca G. Haiduc Martin Brandenberger Sébastien Suquet Frédéric Vogel Rizlan Bernier-Latmani Christian Ludwig 《Journal of applied phycology》2009,21(5):529-541
We describe a potential novel process (SunCHem) for the production of bio-methane via hydrothermal gasification of microalgae,
envisioned as a closed-loop system, where the nutrients, water, and CO2 produced are recycled. The influence on the growth of microalgae of nickel, a trace contaminant that might accumulate upon
effluent recycling, was investigated. For all microalgae tested, the growth was adversely affected by the nickel present (1,
5, and 10 ppm). At 25 ppm Ni, complete inhibition of cell division occurred. Successful hydrothermal gasification of the microalgae
Phaeodactylum tricornutum to a methane-rich gas with high carbon gasification efficiency (68–74%) and C1–C3 hydrocarbon yields of 0.2 gC1–C3/gDM (DM, dry matter) was demonstrated. The biomass-released sulfur was shown to adversely affect Ru/C catalyst performance. Liquefaction
of P. tricornutum at short residence times around 360°C was possible without coke formation. 相似文献
65.
Anca Raˇdulescu 《Journal of theoretical biology》2009,259(2):269-279
We discuss the possibility of multiple underlying etiologies of the condition currently labeled as schizophrenia. We support this hypothesis with a theoretical model of the prefrontal-limbic system.We show how the dynamical behavior of this model depends on an entire set of physiological parameters, representing synaptic strengths, vulnerability to stress-induced cortisol, dopamine regulation and rates of autoantibody production. Malfunction of such different parameters produces similar outward dysregulation of the system, which may readily lead to diagnostic difficulties for a clinician.Techniques that provide a spectrum/profile of neural and steroid functions may be helpful in clarifying these diagnostic dilemmas. 相似文献
66.
Jan Naujoks Christoph Tabeling Brian D. Dill Christine Hoffmann Andrew S. Brown Mareike Kunze Stefan Kempa Andrea Peter Hans-Joachim Mollenkopf Anca Dorhoi Olivia Kershaw Achim D. Gruber Leif E. Sander Martin Witzenrath Susanne Herold Andreas Nerlich Andreas C. Hocke Ian van Driel Norbert Suttorp Sammy Bedoui Hubert Hilbi Matthias Trost Bastian Opitz 《PLoS pathogens》2016,12(2)
67.
Cristian Capitanescu Anca Monica Macovei Oprescu Dan Ionita Gabi Valeriu Dinca Claudiu Turculet Gheorghe Manole 《Journal of enzyme inhibition and medicinal chemistry》2016,31(6):1411-1414
The aim of this research is to evaluate the current streptokinase thrombolytic treatment and to identify or improve new techniques that will base new approaches with a higher efficiency in this area of expertise. In order to be as realistic as possible a new method was set up using magnetic vectorized nanoparticles streptokinase and human blood thrombus. The experimental data confirm the maximum 83% thrombus lyses whenever increase streptokinase concentration. It is very probable to happen because of the presence of high concentration of antiplasmin in the blood that neutralizes around half of the thrombolytic potential of the sanguine plasminogen. The experiment shows also that only free serum plasminogen are available for streptokinase action in order to generate plasmin. 相似文献
68.
69.
Margineanu A De Feyter S Melnikov S Marchand D van Aerschot A Herdewijn P Habuchi S De Schryver FC Hofkens J 《Biomacromolecules》2007,8(11):3382-3392
Lipoplex formation for normal and cholesterol-modified oligonucleotides is investigated by fluorescence correlation spectroscopy (FCS). To overcome the problems related to the fitting of autocorrelation curves when fluorescence bursts are present, the baseline fluorescence levels and the fluorescence bursts in the same trace were separately analyzed. This approach was not previously used in FCS studies of lipoplexes and allowed a more detailed characterization of this heterogeneous system. From the baseline levels, the number of free/bound DNA molecules and the presence of tens to hundreds of nanometer-sized lipoplexes were estimated using various mathematical models. Analysis of the fluorescent bursts provided an indication about the sizes of the lipoplexes, the number of DNA molecules in these aggregates, and the relative amount of lipids in each aggregate. An explanation for the higher transfection efficiency previously reported for one of the cholesterol-modified oligonucleotide compounds was found in relation to the formation of large size lipoplexes. 相似文献
70.
Foam cell‐derived 4‐hydroxynonenal induces endothelial cell senescence in a TXNIP‐dependent manner
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Yael Riahi Nurit Kaiser Guy Cohen Ihab Abd‐Elrahman Galia Blum Oz M. Shapira Tomer Koler Maya Simionescu Anca V. Sima Neven Zarkovic Kamelija Zarkovic Marica Orioli Giancarlo Aldini Erol Cerasi Gil Leibowitz Shlomo Sasson 《Journal of cellular and molecular medicine》2015,19(8):1887-1899
Vascular endothelial cell (VEC) senescence is considered an early event in the development of atherosclerotic lesions. Stressful stimuli, in particular oxidative stress, have been linked to premature senescence in the vasculature. Foam cells are a major source of reactive oxygen species and may play a role in the induction of VEC senescence; hence, we investigated their involvement in the induction of VEC senescence in a co‐culture transwell system. Primary bovine aortic endothelial cells, exposed to the secretome of THP‐1 monocyte‐derived foam cells, were analysed for the induction of senescence. Senescence associated β‐galactosidase activity and the expression of p16 and p21 were increased, whereas phosphorylated retinoblastoma protein was reduced. This senescent phenotype was mediated by 4‐hydroxnonenal (4‐HNE), a lipid peroxidation product secreted from foam cells; scavenging of 4‐HNE in the co‐culture medium blunted this effect. Furthermore, both foam cells and 4‐HNE increased the expression of the pro‐oxidant thioredoxin‐interacting protein (TXNIP). Molecular manipulation of TXNIP expression confirmed its involvement in foam cell‐induced senescence. Previous studies showed that peroxisome proliferator‐activated receptor (PPAR)δ was activated by 4‐hydroalkenals, such as 4‐HNE. Pharmacological interventions supported the involvement of the 4‐HNE‐PPARδ axis in the induction of TXNIP and VEC senescence. The association of TXNIP with VEC senescence was further supported by immunofluorescent staining of human carotid plaques in which the expression of both TXNIP and p21 was augmented in endothelial cells. Collectively, these findings suggest that foam cell‐released 4‐HNE activates PPARδ in VEC, leading to increased TXNIP expression and consequently to senescence. 相似文献