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421.
422.
Song-Zhi Kong Yan-Fang Xian Siu-Po Ip Xiao-Ping Lai Xu-Guang Shi Zhi-Xiu Lin Zi-Ren Su 《Neurochemical research》2013,38(5):951-960
The accumulation of extracellular amyloid-β peptide (Aβ) has been considered as one of the important causes of Alzheimer’s disease (AD), the most prevalent form of dementia. Hydroxysafflor yellow A (HSYA), a major active chemical component isolated from Carthamus tinctorius L., has been shown to possess neuroprotective actions in various ischemic models in vivo. The present study aimed to investigate the potential protective effect of HSYA against Aβ-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. The PC12 cells were pretreated with different concentrations (20, 40 and 80 μM) of HSYA for 2 h and then further treated with Aβ (20 μM) for 24 h. The results showed that Aβ could significantly decrease cell viability, glutathione level, mitochondrial membrane potential and the ratio of Bcl-2/Bax protein expression, while elevate the release of lactate dehydrogenase, the formation of DNA fragmentation, the levels of malondialdehyde and intracellular reactive oxygen species in PC12 cells. However, pretreatment with HSYA could effectively reverse these changes induced by Aβ in PC12 cells. Our experimental results demonstrate that HSYA may be a potential neuroprotective agent warranting further development for treatment of AD. 相似文献
423.
Duncan H. F. Mak Siu-Po Ip Pui-Chun Li Michel K. T. Poon Kam-Ming Ko 《Molecular and cellular biochemistry》1996,165(2):161-165
Effects of Schisandrin B (Sch B) and -tocopherol (-TOC) on ferric chloride (Fe3+) induced oxidation of erythrocyte membrane lipids in vitro and carbon tetrachloride (CCl4) induced lipid peroxidation in vivo were examined. While -TOC could produce prooxidant and antioxidant effect on Fe3+-induced lipid peroxidation, Sch B only inhibited the peroxidation reaction. Pretreatment with -TOC (3 mmol/kg/day × 3) did not protect against CCl4-induced lipid peroxidation and hepatocellular damage in mice, whereas Sch B pretreatment (0.3 mmol/3.0 mmol/kg/day × 3) produced a dose-dependent protective effect on the CCl4-induced hepatotoxicity. The ensemble of results suggests that the ability of Sch B to inhibit lipid peroxidation, while in the absence of pro-oxidant activity, may at least in part contribute to its hepatoprotective action.Abbreviations
ALT
alanine aminotransferase
- CCl4
carbon tetrachloride
- Fe3+
ferric chloride
- MDA
malondialdehyde
- Sch B
Schisandrin B
- TBA
2-thiobarbituric acid
- TBARS
thiobarbituric acid reactive substances
- -TOC
dl--tocopherol 相似文献
424.
Haemin attenuates intermittent hypoxia‐induced cardiac injury via inhibiting mitochondrial fission
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Qian Han Guihua Li Mary SiuMan Ip Yuelin Zhang Zhe Zhen Judith ChoiWo Mak Nuofu Zhang 《Journal of cellular and molecular medicine》2018,22(5):2717-2726
Obstructive sleep apnoea (OSA) characterized by intermittent hypoxia (IH) is closely associated with cardiovascular diseases. IH confers cardiac injury via accelerating cardiomyocyte apoptosis, whereas the underlying mechanism has remained largely enigmatic. This study aimed to explore the potential mechanisms involved in the IH‐induced cardiac damage performed with the IH‐exposed cell and animal models and to investigate the protective effects of haemin, a potent haeme oxygenase‐1 (HO‐1) activator, on the cardiac injury induced by IH. Neonatal rat cardiomyocyte (NRC) was treated with or without haemin before IH exposure. Eighteen male Sprague‐Dawley (SD) rats were randomized into three groups: control group, IH group (PBS, ip) and IH + haemin group (haemin, 4 mg/kg, ip). The cardiac function was determined by echocardiography. Mitochondrial fission was evaluated by Mitotracker staining. The mitochondrial dynamics‐related proteins (mitochondrial fusion protein, Mfn2; mitochondrial fission protein, Drp1) were determined by Western blot. The apoptosis of cardiomyocytes and heart sections was examined by TUNEL. IH regulated mitochondrial dynamics‐related proteins (decreased Mfn2 and increased Drp1 expressions, respectively), thereby leading to mitochondrial fragmentation and cell apoptosis in cardiomyocytes in vitro and in vivo, while haemin‐induced HO‐1 up‐regulation attenuated IH‐induced mitochondrial fragmentation and cell apoptosis. Moreover, IH resulted in left ventricular hypertrophy and impaired contractile function in vivo, while haemin ameliorated IH‐induced cardiac dysfunction. This study demonstrates that pharmacological activation of HO‐1 pathway protects against IH‐induced cardiac dysfunction and myocardial fibrosis through the inhibition of mitochondrial fission and cell apoptosis. 相似文献
425.
426.
427.
Characterization of Novel Orange Fluorescent Protein Cloned from Cnidarian Tube Anemone <Emphasis Type="Italic">Cerianthus</Emphasis> sp. 总被引:1,自引:0,他引:1
A novel orange fluorescent protein (OFP) was cloned from the tentacles of Cnidarian tube anemone Cerianthus sp. It consists of 222 amino acid residues with a calculated molecular mass of 25.1 kDa. A BLAST protein sequence homology
search revealed that native OFP has 81% sequence identity to Cerianthus membranaceus green fluorescent protein (cmFP512), 38% identity to Entacmaea quadricolor red fluorescent protein (eqFP611), 37% identity to Discosoma red fluorescent protein (DsRed), 36% identity to Fungia concinna Kusabira-orange fluorescent protein (KO), and a mere 21% identity to green fluorescent protein (GFP). It is most likely that
OFP also adopts the 11-strand β-barrel structure of fluorescent proteins. Spectroscopic analysis indicated that it has a wide
absorption spectrum peak at 548 nm with two shoulders at 487 and 513 nm. A bright orange fluorescence maximum at 573 nm was
observed when OFP was excited at 515 nm or above. When OFP was excited well below 515 nm, a considerable amount of green emission
maximum at 513 nm was also observed. It has a fluorescence quantum yield (Φ) of 0.64 at 25°C. The molar absorption coefficients
(ɛ) of folded OFP at 278 and 548 nm are 47,000 and 60,000 M-1−1 • cm-1−1, respectively. Its fluorescent brightness (ɛ Φ) at 25°C is 38,400 M−1-1 • cm−1-1. Like other orange-red fluorescent proteins, OFP is also tetrameric. It was readily expressed as soluble protein in Escherichia coli at 37°C, and no aggregate was observed in transfected HeLa cells under our experimental conditions. Fluorescent intensity
of OFP is detectable over a pH range of 3 to 12. 相似文献
428.
Marcelo Filonzi Laís C Cardoso Maristela T Pimenta Daniel BC Queiróz Maria CW Avellar Catarina S Porto Maria FM Lazari 《Reproductive biology and endocrinology : RB&E》2007,5(1):29
Background
Relaxin is the endogenous ligand of the G-protein coupled receptor RXFP1, previously known as LGR7. In humans relaxin can also activate, but with lower affinity, the closely related receptor for the insulin-like peptide from Leydig cells, RXFP2, previously known as LGR8. The lack of relaxin impairs male fertility but the precise distribution and the function of relaxin receptors in the male reproductive tract is not known. We investigated the distribution of Rxfp1 and Rxfp2 in the reproductive tract of the male rat and the function of relaxin in the vas deferens, a tissue with high expression of both receptors. 相似文献429.
Cdk5 is involved in BDNF-stimulated dendritic growth in hippocampal neurons 总被引:2,自引:0,他引:2
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Neurotrophins are key regulators of neuronal survival and differentiation during development. Activation of their cognate receptors, Trk receptors, a family of receptor tyrosine kinases (RTKs), is pivotal for mediating the downstream functions of neurotrophins. Recent studies reveal that cyclin-dependent kinase 5 (Cdk5), a serine/threonine kinase, may modulate RTK signaling through phosphorylation of the receptor. Given the abundant expression of both Cdk5 and Trk receptors in the nervous system, and their mutual involvement in the regulation of neuronal architecture and synaptic functions, it is of interest to investigate if Cdk5 may also modulate Trk signaling. In the current study, we report the identification of TrkB as a Cdk5 substrate. Cdk5 phosphorylates TrkB at Ser478 at the intracellular juxtamembrane region of TrkB. Interestingly, attenuation of Cdk5 activity or overexpression of a TrkB mutant lacking the Cdk5 phosphorylation site essentially abolishes brain-derived neurotrophic factor (BDNF)–triggered dendritic growth in primary hippocampal neurons. In addition, we found that Cdk5 is involved in BDNF-induced activation of Rho GTPase Cdc42, which is essential for BDNF-triggered dendritic growth. Our observations therefore reveal an unanticipated role of Cdk5 in TrkB-mediated regulation of dendritic growth through modulation of BDNF-induced Cdc42 activation. 相似文献
430.
Fortes P Longman D McCracken S Ip JY Poot R Mattaj IW Cáceres JF Blencowe BJ 《FEBS letters》2007,581(16):3087-3097
Precursor (pre)-mRNA splicing can impact the efficiency of coupled steps in gene expression. SRm160 (SR-related nuclear matrix protein of 160 kDa), is a splicing coactivator that also functions as a 3'-end cleavage-stimulatory factor. Here, we have identified an evolutionary-conserved SRm160-interacting protein, referred to as hRED120 (for human Arg/Glu/Asp-rich protein of 120 kDa). hRED120 contains a conventional RNA recognition motif and, like SRm160, a PWI nucleic acid binding domain, suggesting that it has the potential to bridge different RNP complexes. Also, similar to SRm160, hRED120 associates with snRNP components, and remains associated with mRNA after splicing. Simultaneous suppression in Caenorhabditis elegans of the ortholog of hRED120 with the orthologs of splicing and 3'-end processing factors results in aberrant growth or developmental defects. These results suggest that RED120 may function to couple splicing with mRNA 3'-end formation. 相似文献