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排序方式: 共有389条查询结果,搜索用时 15 毫秒
31.
Jemnitz K Lengyel G Vereczkey L 《Biochemical and biophysical research communications》2002,291(1):29-33
UDP-glucuronosyltransferase (UGT1A1) is a critical enzyme in the elimination of bilirubin. The aim of our study was to investigate bilirubin conjugation in primary rat hepatocyte culture and the in vitro inducibility of this isoenzyme by inducing compounds of different classes: dexamethasone, clofibrate, rifampicin, and methylcholanthrene. Hepatocytes exhibited a marked decline in UGT1A1 activity in the first 4 h of culturing (10% of initial activity) and the recovery took 72 h. Immunoblot analysis proved that the loss of enzyme activity was associated with the decrease of protein concentration. Marked induction was detected in the cases of dexamethasone, clofibrate, and rifampicin treatments for 96 h both in enzyme activity (178, 176, and 168%) and in UGT1A1 protein level (362, 328, and 250%). The effects of dexamethasone and clofibrate were additive (210%). Methylcholanthrene had no influence on bilirubin conjugation in our system. 相似文献
32.
beta(3)A-integrin downregulates the urokinase-type plasminogen activator receptor (u-PAR) through a PEA3/ets transcriptional silencing element in the u-PAR promoter
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Hapke S Gawaz M Dehne K Köhler J Marshall JF Graeff H Schmitt M Reuning U Lengyel E 《Molecular and cellular biology》2001,21(6):2118-2132
33.
During different behavioral states different population activities are present in the hippocampal formation. These activities
are not independent: sharp waves often occur together with high-frequency ripples, and gamma-frequency activity is usually
superimposed on theta oscillations. There is both experimental and theoretical evidence supporting the notion that gamma oscillation
is generated intrahippocampally, but there is no generally accepted view about the origin of theta waves. Precise timing of
population bursts of pyramidal cells may be due to a synchronized external drive. Membrane potential oscillations recorded
in the septum are unlikely to fulfill this purpose because they are not coherent enough. We investigated the prospects of
an intrahippocampal mechanism supplying pyramidal cells with theta frequency periodic inhibition, by studying a model of a
network of hippocampal inhibitory interneurons. As shown previously, interneurons are capable of generating synchronized gamma-frequency
action potential oscillations. Exciting the neurons by periodic current injection, the system could either be entrained in
an oscillation with the frequency of the inducing current or exhibit in-phase periodic changes at the frequency of single
cell (and network) activity. Simulations that used spatially inhomogeneous stimulus currents showed anti-phase frequency changes
across cells, which resulted in a periodic decrease in the synchrony of the network. As this periodic change in synchrony
occurred in the theta frequency range, our network should be able to exhibit the theta-frequency weakening of inhibition of
pyramidal cells, thus offering a possible mechanism for intrahippocampal theta generation.
Received: 23 February 2000 / Accepted in revised form: 30 June 2000 相似文献
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Marijn Rutgers Daniël BF Saris Wouter JA Dhert Laura B Creemers 《Arthritis research & therapy》2010,12(3):R114
Introduction
Intraarticular administration of autologous conditioned serum (ACS) recently demonstrated some clinical effectiveness in treatment of osteoarthritis (OA). The current study aims to evaluate the in vitro effects of ACS on cartilage proteoglycan (PG) metabolism, its composition and the effects on synovial fluid (SF) cytokine levels following intraarticular ACS administration. 相似文献38.
Nikolett Kállai Oliver Luhn Judit Dredán Kristóf Kovács Miléna Lengyel István Antal 《AAPS PharmSciTech》2010,11(1):383-391
The objective of the present study was to investigate the effect of the pellet core materials isomalt, sugar, and microcrystalline cellulose on the in vitro drug release kinetics of coated sustained-release pellets as well as to evaluate the influence of different ratios of polymethacrylate copolymers exhibiting different permeability characteristics on the drug release rate. For characterization of the drug release process of pellets, the effect of osmolality was studied using glucose as an osmotically active agent in the dissolution medium. The pellet cores were layered with diclofenac sodium as model drug and coated with different ratios of Eudragit® RS30D and Eudragit® RL30D (ERS and ERL; 0:1 and 0.5:0.5 and 1:0 ratio) in a fluid bed apparatus. Physical characteristics such as mechanical strength, shape, and size proved that the inert cores were adequate for further processing. The in vitro dissolution tests were performed using a USP Apparatus I (basket method). The results demonstrated that, besides the ratio of the coating polymers (ERS/ERL), the release mechanism was also influenced by the type of starter core used. Sugar- and isomalt-type pellet cores demonstrated similar drug release profiles. 相似文献
39.
Young adult male Wistar rats were treated, by gavage, with 80 or 320 mg/kg Pb2+ (lead acetate), 0.4 or 1.6 mg/kg Hg2+ (mercuric chloride) or both by combining the lower doses. For combination with alcohol, ethanol was added to the rats' drinking water in 5 v/v %. After 12 weeks of treatment, electrophysiological recording was made from the somatosensory cortex in urethane anaesthesia. Evoked potentials obtained by stimulation of the whiskers were recorded. Both metals, and alcohol alone, increased significantly the latency of the evoked response. Alcohol seemed to abolish the effect of Pb, but not of Hg. Fatigue, calculated form the response amplitude, was increased by Pb and Hg treatment and this effect of Hg was reduced by ethanol. Evoked activity and its dynamic characteristics were sensitive to the complex neurotoxic effect induced in the rats and can provide a basis for developing functional markers. 相似文献
40.
Phosphorylation of PTEN (phosphatase and tensin homologue deleted on chromosome ten) protein is enhanced in human fibromyomatous uteri 总被引:1,自引:0,他引:1
Kovács KA Lengyel F Vértes Z Környei JL Gocze PM Sumegi B Szabó I Vértes M 《The Journal of steroid biochemistry and molecular biology》2007,103(2):196-199
PTEN phosphatase, a product of PTEN tumor suppressor gene, exists in cells in phosphorylated and unphosphorylated form and has a central role in regulation of PI3K/Akt signalling which is involved in non-genomic action of estradiol. The purpose of this study was to analyze the level of total PTEN and phosphoPTEN parallel to phosphoAkt in leiomyoma and adjacent myometrium during menstrual cycle and at menopause. The expression of total PTEN in leiomyoma and myometrium did not change throughout the experiments. However, the level of phosphoPTEN was increased in leiomyoma during menstrual cycle. The phosphorylation of PTEN in myometrium was lower during secretory phase than that of proliferative phase. The phosphoAkt was abundant in leiomyoma, and its expression was higher during menstrual cycle than in myometrium. The phosphorylation of PTEN was directly related to phosphoAkt, suggesting a direct link between the inactivation of PTEN and activation of Akt. At the decline of sexual steroids, at menopause, no differences were observed in the expression of studied proteins between the two types of tissues. Our results suggest that the altered phosphorylation of PTEN protein and the consequent activation of survival signals may contribute to the pathomechanism of leiomyoma. 相似文献