全文获取类型
收费全文 | 293篇 |
免费 | 13篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 12篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 9篇 |
2016年 | 20篇 |
2015年 | 16篇 |
2014年 | 24篇 |
2013年 | 30篇 |
2012年 | 34篇 |
2011年 | 19篇 |
2010年 | 15篇 |
2009年 | 9篇 |
2008年 | 10篇 |
2007年 | 21篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有306条查询结果,搜索用时 15 毫秒
141.
We report on a jumping translocation with five different cell lines detected in four tissues in a 2-year-old patient. This rare type of chromosomal abnormality (not more than 30 cases published so far) proved to be a series of non-reciprocal translocations of the 15q24-qter donor chromosome segment to the telomeric region of chromosomes 5q, 10q, 16q and 19p, respectively. The process, in addition to a few cells without translocation, resulted in partial trisomy of 15q24-qter which was associated with somatic overdevelopment in the patient, with hemihypertrophy and minor anomalies. The phenotype of our patient was different from that of the other two patients found in the literature having the same donor chromosome segment involved in a similar rearrangement. Possibly, the difference in the phenotype lies in the various ratios of somatic mosaicism with five cell lines, in particular the presence of normal one which is extremely rare in patients with jumping translocation. Here we discuss the various ways on how the rearrangement could arise. 相似文献
142.
Kleveta G Borzęcka K Zdioruk M Czerkies M Kuberczyk H Sybirna N Sobota A Kwiatkowska K 《Journal of cellular biochemistry》2012,113(1):80-92
Upon bacterial infection lipopolysaccharide (LPS) induces migration of monocytes/macrophages to the invaded region and production of pro‐inflammatory mediators. We examined mechanisms of LPS‐stimulated motility and found that LPS at 100 ng/ml induced rapid elongation and ruffling of macrophage‐like J774 cells. A wound‐healing assay revealed that LPS also activated directed cell movement that was followed by TNF‐α production. The CD14 and TLR4 receptors of LPS translocated to the leading lamella of polarized cells, where they transiently colocalized triggering local accumulation of actin filaments and phosphatidylinositol 4,5‐bisphosphate. Fractionation of Triton X‐100 cell lysates revealed that LPS induced polymerization of cytoskeletal actin filaments by 50%, which coincided with the peak of cell motility. This microfilament population appeared at the expense of short filaments composing the plasma membrane skeleton of unstimulated cells and actin monomers consisting prior to the LPS stimulation about 60% of cellular actin. Simultaneously with actin polymerization, LPS stimulated phosphorylation of two actin‐regulatory proteins, paxillin on tyrosine 118 by 80% and N‐WASP on serine 484/485 by 20%, and these events preceded activation of NF‐κB. LPS‐induced protein phosphorylation and reorganization of the actin cytoskeleton were inhibited by PP2, a drug affecting activity of tyrosine kinases of the Src family. The data indicate that paxillin and N‐WASP are involved in the reorganization of actin cytoskeleton driving motility of LPS‐stimulated cells. Disturbances of actin organization induced by cytochalasin D did not inhibit TNF‐α production suggesting that LPS‐induced cell motility is not required for TNF‐α release. J. Cell. Biochem. 113: 80–92, 2012. © 2011 Wiley Periodicals, Inc. 相似文献
143.
Malondialdehyde plasma concentration correlates with declarative and working memory in patients with recurrent depressive disorder 总被引:1,自引:0,他引:1
Talarowska M Gałecki P Maes M Gardner A Chamielec M Orzechowska A Bobińska K Kowalczyk E 《Molecular biology reports》2012,39(5):5359-5366
Oxidative stress has been implicated in the cognitive decline, especially in memory impairment. The purpose of this study
was to determine the concentration of malondialdehyde (MDA) in patients with recurrent depressive disorders (rDD) and to define
relationship between plasma levels of MDA and the cognitive performance. The study comprised 46 patients meeting criteria
for rDD. Cognitive function assessment was based on: The Trail Making Test , The Stroop Test, Verbal Fluency Test and Auditory-Verbal
Learning Test. The severity of depression symptoms was assessed using the Hamilton Depression Rating Scale (HDRS). Statistically
significant differences were found in the intensity of depression symptoms, measured by the HDRS on therapy onset versus the
examination results after 8 weeks of treatment (P < 0.001). Considering the 8-week pharmacotherapy period, rDD patients presented better outcomes in cognitive function tests.
There was no statistically significant correlation between plasma MDA levels, and the age, disease duration, number of previous
depressive episodes and the results in HDRS applied on admission and on discharge. Elevated levels of MDA adversely affected
the efficiency of visual-spatial and auditory-verbal working memory, short-term declarative memory and the delayed recall
declarative memory. 1. Higher concentration of plasma MDA in rDD patients is associated with the severity of depressive symptoms,
both at the beginning of antidepressants pharmacotherapy, and after 8 weeks of its duration. 2. Elevated levels of plasma
MDA are related to the impairment of visual-spatial and auditory-verbal working memory and short-term and delayed declarative
memory. 相似文献
144.
Ocskó T Gálfi M Radács M Molnár Z Kis GK Rákosi K Molnár AH László F László FA Varga C 《Regulatory peptides》2012,175(1-3):43-48
The effects of orexin-monoaminergic compound interactions on oxytocin release were studied in 14-day rat neurohypophyseal cell cultures prepared by an enzymatic dissociation technique. The oxytocin contents of the supernatants were determined by radioimmunoassay. Following the administration of orexin-A or orexin-B in increasing doses, significant changes were not observed in the oxytocin content of the supernatant media. The oxytocin level increased substantially in response to adrenaline, noradrenaline, serotonin, histamine, dopamine or K(+) treatment. Preincubation with orexin-A or orexin-B reduced the adrenaline-, histamine- or serotonin-induced oxytocin level increases, but the oxytocin concentrations of the supernatant media remained above the control level. There was no significant difference in decreasing effect between orexin-A and orexin-B. Neither orexin-A nor orexin-B induced changes in oxytocin release following monoaminergic compound treatment. The results indicate that the changes in oxytocin secretion induced by the monoaminergic system can be directly influenced by the orexin system. The effects of orexin on oxytocin release can be antagonized by an orexin-1 receptor-specific antagonist. It may be presumed that the orexins can play a role in the pathogenetic process of metabolic diseases (e.g. obesity) by reducing the effects of increased oxytocin release caused by monoaminergic compounds. The interactions between the monoaminergic and orexin systems regarding oxytocin secretion occur at both the hypothalamic and the neurohypophyseal levels. 相似文献
145.
Salicylic acid content and benzoic acid 2-hydroxylase (BA2H) activity were investigated in tobacco Bel-W3 and Bel-B leaves after exposure to tropospheric ozone in the conditions of ambient air. Plants were exposed in accordance with a standard methodology for ozone biomonitoring, in a three-year experiment. Free salicylic acid (SA), conjugated with glucose (SAG), and as a product of the BA2H activity was quantified with HPLC. In order to evaluate ozone injuries of leaves, an open source image analysis software was employed. Plants exposure to ambient ozone resulted in enhanced BA2H activity and intensified salicylic acid biosynthesis in leaves of Bel-W3 cultivar showing visible ozone injuries. The BA2H activity significantly correlated with SAG for ozone-exposed Bel-W3 plants. Both injuries and salicylic acid biosynthesis rate depended on the growth phase of leaves and nearly linear correlation between SA content and injuries was found for particular leaves of Bel-W3. 相似文献
146.
Maksym I. Harhun Christopher L. Huggins Kumaran Ratnasingham Durgesh Raje Ray F. Moss Kinga Szewczyk Georgios Vasilikostas Iain A. Greenwood Teck K. Khong Andrew Wan Marcus Reddy 《Journal of cellular and molecular medicine》2012,16(11):2802-2812
Vascular interstitial cells (VICs) are non‐contractile cells with filopodia previously described in healthy blood vessels of rodents and their function remains unknown. The objective of this study was to identify VICs in human arteries and to ascertain their role. VICs were identified in the wall of human gastro‐omental arteries using transmission electron microscopy. Isolated VICs showed ability to form new and elongate existing filopodia and actively change body shape. Most importantly sprouting VICs were also observed in cell dispersal. RT‐PCR performed on separately collected contractile vascular smooth muscle cells (VSMCs) and VICs showed that both cell types expressed the gene for smooth muscle myosin heavy chain (SM‐MHC). Immunofluorescent labelling showed that both VSMCs and VICs had similar fluorescence for SM‐MHC and αSM‐actin, VICs, however, had significantly lower fluorescence for smoothelin, myosin light chain kinase, h‐calponin and SM22α. It was also found that VICs do not have cytoskeleton as rigid as in contractile VSMCs. VICs express number of VSMC‐specific proteins and display features of phenotypically modulated VSMCs with increased migratory abilities. VICs, therefore represent resident phenotypically modulated VSMCs that are present in human arteries under normal physiological conditions. 相似文献
147.
Stájer A Urbán E Pelsõczi IK Mihalik E Rakonczay Z Nagy K Turzó K Radnai M 《Acta microbiologica et immunologica Hungarica》2012,59(1):51-61
Fluorides may affect the oxide layer on titanium surface. Caries preventive mouthwashes or gels contain fluorides and are applied at low pH. The aim of the present work was to study whether various concentrations of fluoride at acidic pH cause changes in the surface structure on the polished region of Ti implants, and alter the adherence and colonization of bacteria. Commercially pure Ti grade 4 discs with a polished surface were treated with a mouthwash containing 0.025% fluoride, a gel containing 1.25% fluoride or a 1% aqueous solution of NaF (pH 4.5). The change of surface roughness of the samples and the colonization of Porphyromonas gingivalis strains were studied by scanning electron microscopy after 5 days of anaerobic incubation. The quantity of the bacterial protein was determined by protein assay analysis. Agents with high fluoride concentration at acidic pH increased the roughness of the Ti surface. A slight increase in the amount of bacteria was found on the surfaces treated with 1% NaF and gel in comparison with the control surface. This study suggested that a high fluoride concentration at acidic pH may hinder the development of a healthy transgingival epithelial junction on Ti implants, due to bacterial colonization. 相似文献
148.
Francesco Venice Stefano Ghignone Alessandra Salvioli di Fossalunga Joëlle Amselem Mara Novero Xie Xianan Kinga Sędzielewska Toro Emmanuelle Morin Anna Lipzen Igor V. Grigoriev Bernard Henrissat Francis M. Martin Paola Bonfante 《Environmental microbiology》2020,22(1):122-141
As members of the plant microbiota, arbuscular mycorrhizal fungi (AMF, Glomeromycotina) symbiotically colonize plant roots. AMF also possess their own microbiota, hosting some uncultivable endobacteria. Ongoing research has revealed the genetics underlying plant responses to colonization by AMF, but the fungal side of the relationship remains in the dark. Here, we sequenced the genome of Gigaspora margarita, a member of the Gigasporaceae in an early diverging group of the Glomeromycotina. In contrast to other AMF, G. margarita may host distinct endobacterial populations and possesses the largest fungal genome so far annotated (773.104 Mbp), with more than 64% transposable elements. Other unique traits of the G. margarita genome include the expansion of genes for inorganic phosphate metabolism, the presence of genes for production of secondary metabolites and a considerable number of potential horizontal gene transfer events. The sequencing of G. margarita genome reveals the importance of its immune system, shedding light on the evolutionary pathways that allowed early diverging fungi to interact with both plants and bacteria. 相似文献
149.
Actions of neuropeptide Y on basal, cyclic AMP-induced and neurally evoked ion transport in porcine distal jejunum 总被引:1,自引:0,他引:1
Neuropeptide Y (NPY) and its homolog, peptide YY, are present respectively in neurons and endocrine cells within the mammalian small intestine. In this study, we examined the actions of NPY on ion transport in the porcine distal jejunum mucosa-submucosa in vitro. Peptide YY and NPY were equieffective in producing rapid and sustained decreases in basal short-circuit current (Isc), a bioelectrical measure of active ion transport, eliciting half-maximal decreases at respective serosal concentrations of 0.8 and 30 nmol/l. NPY-induced changes in Isc were due to increased mucosa-to-serosa and net Cl fluxes and were not affected by the absence of extracellular HCO3 ions. NPY activity was correlated with the magnitude of the basal Isc and appeared to depend on the spontaneous production of eicosanoids. The peptide also decreased Isc stimulated by forskolin and 8-bromo-cyclic AMP, but the ionic bases for this effect were complex and differed from those determined under basal conditions. NPY attenuated increases in Isc produced by electrical stimulation of enteric neurons with an IC50 = 5 nmol/l. The actions of the peptide on basal and cyclic AMP-induced ion transport were abolished by the neuronal conduction blocker tetrodotoxin, but not by the opiate antagonist naloxone. The alpha-adrenoceptor blocker phentolamine diminished the effects of NPY on basal, but not cyclic AMP-induced Isc. These results indicate that NPY is capable of modulating NaCl transport in the porcine jejunal mucosa under several different conditions. Furthermore, the effects of the peptide are mediated in part through noradrenergic nerves as well as enteric neurons of unknown chemical identity. 相似文献
150.
Juliusz Perkowski Maciej Buśko Kinga Stuper Marian Kostecki Anna Matysiak Lidia Szwajkowska-Michałek 《Biologia》2008,63(4):542-547
Ergosterol (ERG) is a major sterol constituent of most fungi. Its concentration is negligible in higher plants, but can be
used as a chemical marker of the presence of fungal contaminations. In this study, ERG concentration was assessed in randomly
collected samples of naturally contaminated grain (wheat, barley and oat) and in samples of grain (wheat, barley, triticale
and oat) harvested after inoculation of heads with conidia of different Fusarium species. Wheat samples were analysed at three stages of grain development. The lowest ERG concentration was found in non-inoculated
samples at the first stage of grain development. This concentration was increasing with grain ripening. In naturally contaminated
samples collected after harvest, ERG concentration was lower in wheat than in barley and oat. ERG concentrations in inoculated
samples varied significantly, but were always significantly higher than in naturally contaminated samples. In the above cereal
samples it was much lower than the levels assayed in laboratory cultures inoculated with fungi from genus Fusarium. The content of ERG was also analyzed in milling products of small-grained cereals and other foodstuffs, where a considerable
variation was observed. The lowest ERG amounts were assayed in flours with a high degree of purification, while the highest
ones in case of flours and products with a low purification rate. The results indicate the potential application of HPLC combined
with microwave-assisted extraction both when assaying samples with low ERG concentrations (naturally contaminated) and those
characterized with high contents of fungal biomass (strongly infected, artificially inoculated). It also facilitates analyses
of fungal biomass in technological processes, where results may be expected to vary considerably. 相似文献