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61.
Metabolic Maturation during Muscle Stem Cell Differentiation Is Achieved by miR-1/133a-Mediated Inhibition of the Dlk1-Dio3 Mega Gene Cluster 总被引:2,自引:0,他引:2
62.
Manfred Keller Rolf Jackisch Andras Seregi Georg Hertting 《Neurochemistry international》1985,7(4):655-665
Prostaglandin (PG) and thromboxane (TX) biosynthesis in primary neuronal and astroglial cell cultures was studied. Cultures obtained from fetal (15–16 days old) and neonatal rat brain hemispheres were characterized by chemical and immunocytochemical staining techniques as predominantly neurons or mature and immature astrocytes, respectively. Six-day old neuronal cell cultures grown in the presence of cytosine arabinoside (2 μM) from the day 3 onwards were contaminated up to 10% with glioblasts. In astroglial cultures up to 3% of the cells were postively stained with a marker for oligodendroglial cells. Fibroblast contamination was below 1% in both cultures. Prostanoid formation (measured by specific radioimmunoassays) in 6-day old neuronal cell cultures was low (sum of the amount of PGs and TX formed: 1.16 ± 0.17 (ng/mg protein/15 min) as compared to 14-day old cultured astroglial cells: 21.27 ± 2.53 (ng/mg protein/15 min). Also the pattern of prostanoids formed was different in neuronal (PGD2 ? PGF2α > TXB2 ? PGE2) and astroglial cells (PGD2 > TXB2 ? PGF2α ? PGE2 ? 6-ketoPGF1α). Preincubation with arachidonic acid (1 μg/ml) did not affect prostanoid formation in both cultures, whereas it was stimulated 4–6-fold by addition of the calcium ionophore A23187 (1 μM). These results, although found on cultured neuronal and glial cells of different stages of development, support the view that astroglial cells might play a crucial role in brain prostanoid synthesis. 相似文献
63.
Pacher Pal Kecskemeti Valeria Ronai Andras Z. Balogh Istvan Gabor Gabor Matkovics Bela 《Molecular and cellular biochemistry》1998,187(1-2):183-190
Human placental syncytiotrophoblast basal membrane plays an important role in transfer of nutrients from the mother to the growing fetus all throughout gestation. The membrane lipid composition together with the bilayer fluidity is found to be the major index in modulation of these transport processes. In the present study, the effects of changing lipid composition on the placental basal membrane fluidity and the modulating influence of the latter on membrane enzyme and transport functions with progress of gestation,were investigated. Steady-state fluorescence analysis using 1,6-diphenyl-1,3,5 hexatriene as the probe, indicated a decrease in fluorescence anisotropy of both labeled native membrane vesicles and liposomes prepared from lipids extracted from the basal membrane vesicles, signifying increased bilayer fluidity with progress of gestation. This in turn, was successfully correlated to the lowering of cholesterol content and enhanced phospholipid concentration with a steady decrease in cholesterol/phospholipid ratio during placental development. Enhanced Na+-K+-ATPase activity and steady-state glucose uptake across basal membrane with gestational progress suggested modulation of membrane protein functions by the fluidity, which was further corroborated by the increased bilayer fluidity and enzyme activity in benzyl alcohol treated basal membrane in each gestational age group. 相似文献
64.
Marlyn Panchoo Andras Lacko 《Biochemical and biophysical research communications》2018,495(1):614-620
Neuroblastoma (NB) is an extra cranial pediatric embryonal tumor most prevalent in children less than 1 year of age. NB accounts for 7% of all pediatric cancers but accounts for 15% of all childhood cancer deaths. Scavenger receptor class B type 1 (SR-B1), a mediator of cellular cholesterol uptake, is overexpressed in and have been linked to the aggressiveness of many cancers. Nevertheless, no studies have so far investigated the relationship between SR-B1 and NB. Elucidation of receptors that promote NB may pave the way for discovery of new therapeutic targets. Here we show that inhibition of SR-B1 reduced cell survival, migration and invasion, and cholesterol content in NB cell lines. Additionally analysis of SR-B1 levels in NB patient biopsies using the R2: Genomics Analysis and Visualization Platform showed that high SR-B1 expression correlated with decreased overall and event-free survival. 相似文献
65.
Adrienn Hanuska Gábor Szénási Mihaly Albert Laszlo Koles Agoston Varga Andras Szabo Peter Matyus Laszlo G. HarsingJr. 《Neurochemical research》2016,41(1-2):73-85
Rat posterior eyecups containing the retina were prepared, loaded with [3H]glycine and superfused in order to determine its release originated from glycinergic amacrine cells and/or glial cells. Deprivation of oxygen and glucose from the Krebs-bicarbonate buffer used for superfusion evoked a marked increase of [3H]glycine release, an effect that was found to be external Ca2+-independent. Whereas oxygen and glucose deprivation increased [3H]glycine release, its uptake was reduced suggesting that energy deficiency shifts glycine transporter type-1 operation from normal to reverse mode. The increased release of [3H]glycine evoked by oxygen and glucose deprivation was suspended by addition of the non-competitive glycine transporter type-1 inhibitor NFPS and the competitive inhibitor ACPPB further suggesting the involvement of this transporter in the mediation of [3H]glycine release. Oxygen and glucose deprivation also evoked [3H]glutamate release from rat retina and the concomitantly occurring release of the NMDA receptor agonist glutamate and the coagonist glycine makes NMDA receptor pathological overstimulation possible in hypoxic conditions. [3H]Glutamate release was suspended by addition of the excitatory amino acid transporter inhibitor TBOA. Sarcosine, a substrate inhibitor of glycine transporter type-1, also increased [3H]glycine release probably by heteroexchange shifting transporter operation into reverse mode. This effect of sarcosine was also external Ca2+-independent and could be suspended by NFPS. Energy deficiency in retina induced by ouabain, an inhibitor of the Na+–K+-dependent ATPase, and by rotenone, a mitochondrial complex I inhibitor added with the glycolytic inhibitor 2-deoxy-d-glucose, led to increase of retinal [3H]glycine efflux. These effects of ouabain and rotenone/2-deoxy-d-glucose could also be blocked by NFPS pointed to the preferential reverse mode operation of glycine transporter type-1 as a consequence of impaired cellular energy homeostasis. Immunohistochemical studies revealed that glycine transporter type-1, of which reverse mode operation assures [3H]glycine release, is expressed in amacrine cells in the inner nuclear and plexiform layers of the retina and also in Müller macroglia cells. We conclude that disruption of the balanced normal/reverse mode operation of glycine transporter type-1 is likely a significant factor contributing to neurotoxic processes of the retina. The possibility to inhibit glycine transporter type-1 mediated glycine efflux by drugs more potently than glycine uptake might offer some therapeutic potential for the treatment of various neurodegenerative disorders of the retina. 相似文献
66.
Chikara Kubota Xiangzhong Yang Andras Dinnyes Junichi Todoroki Hiroshi Yamakuchi Kazunori Mizoshita Satoru Inohae Norio Tabara 《Molecular reproduction and development》1998,51(3):281-286
Cryopreservation of bovine oocytes would be beneficial both for nuclear transfer and for preservation efforts. The overall objective of this study was to evaluate the viability as well as the cryodamage to the nucleus vs. cytoplasm of bovine oocytes following freezing-thawing of oocytes at immature (GV) and matured (MII) stages using in vitro fertilization (IVF), parthenogenetic activation, or nuclear transfer assays. Oocytes were collected from slaughterhouse ovaries. Oocytes at the GV, MII, or MII but enucleated (MIIe) stages were cryopreserved in 5% (v/v) ethylene glycol; 6% (v/v) 1,2-propanediol; and 0.1-M sucrose in PBS supplemented with 20% (v/v) fetal bovine serum. Frozen-thawed oocytes were subjected to IVF, parthenogenetic activation, or nuclear transfer assays. Significantly fewer GV oocytes survived (i.e., remained morphologically intact during freezing-thawing) than did MII oocytes (47% vs. 84%). Subsequent development of the surviving frozen-thawed GV and MII oocytes was not different (58% and 60% cleavage development; 7% and 12% blastocyst development at Day 9, respectively, P > 0.05). Parthenogenetic activation of frozen-thawed oocytes resulted in significantly lower rates of blastocyst development for the GV than the MII oocyte groups (1% vs. 14%). Nuclear transfer with cytoplasts derived from frozen-thawed GV, MII, MIIe, and fresh-MII control oocytes resulted in 5%, 16%, 14%, and 17% blastocyst development, respectively. However, results of preliminary embryo transfer trials showed that fewer pregnancies were produced from cloned embryos derived from frozen oocytes or cytoplasts (9%, n = 11 embryos) than from fresh ones (19%, n = 21 embryos). Transfer of embryos derived by IVF from cryopreserved GV and MII oocytes also resulted in term development of calves. Our results showed that both GV and MII oocytes could survive freezing and were capable of developing into offspring following IVF or nuclear transfer. However, blastocyst development of frozen-thawed oocytes remains poorer than that of fresh oocytes, and our nuclear transfer assay suggests that this poorer development was likely caused by cryodamage to the oocyte cytoplasm as well as to the nucleus. Mol. Reprod. Dev. 51:281–286, 1998. © 1998 Wiley-Liss, Inc. 相似文献
67.
Arora PD Conti MA Ravid S Sacks DB Kapus A Adelstein RS Bresnick AR McCulloch CA 《Molecular biology of the cell》2008,19(12):5032-5046
Rap1 enhances integrin-mediated adhesion but the link between Rap1 activation and integrin function in collagen phagocytosis is not defined. Mass spectrometry of Rap1 immunoprecipitates showed that the association of Rap1 with nonmuscle myosin heavy-chain II-A (NMHC II-A) was enhanced by cell attachment to collagen beads. Rap1 colocalized with NM II-A at collagen bead-binding sites. There was a transient increase in myosin light-chain phosphorylation after collagen-bead binding that was dependent on myosin light-chain kinase but not Rho kinase. Inhibition of myosin light-chain phosphorylation, but not myosin II-A motor activity inhibited collagen-bead binding and Rap activation. In vitro binding assays demonstrated binding of Rap1A to filamentous myosin rods, and in situ staining of permeabilized cells showed that NM II-A filaments colocalized with F-actin at collagen bead sites. Knockdown of NM II-A did not affect talin, actin, or β1-integrin targeting to collagen beads but targeting of Rap1 and vinculin to collagen was inhibited. Conversely, knockdown of Rap1 did not affect localization of NM II-A to beads. We conclude that MLC phosphorylation in response to initial collagen-bead binding promotes NM II-A filament assembly; binding of Rap1 to myosin filaments enables Rap1-dependent integrin activation and enhanced collagen phagocytosis. 相似文献
68.
MOTIVATION: Prediction of disulfide bond connectivity facilitates structural and functional annotation of proteins. Previous studies suggest that cysteines of a disulfide bond mutate in a correlated manner. RESULTS: We developed a method that analyzes correlated mutation patterns in multiple sequence alignments in order to predict disulfide bond connectivity. Proteins with known experimental structures and varying numbers of disulfide bonds, and that spanned various evolutionary distances, were aligned. We observed frequent variation of disulfide bond connectivity within members of the same protein families, and it was also observed that in 99% of the cases, cysteine pairs forming non-conserved disulfide bonds mutated in concert. Our data support the notion that substitution of a cysteine in a disulfide bond prompts the substitution of its cysteine partner and that oxidized cysteines appear in pairs. The method we developed predicts disulfide bond connectivity patterns with accuracies of 73, 69 and 61% for proteins with two, three and four disulfide bonds, respectively. 相似文献
69.
Borković SS Pavlović SZ Kovacević TB Stajn AS Petrović VM Saicić ZS 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2008,147(1):122-128
The aim of our study was to determine the activity of antioxidant defence (AD) enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and the phase II biotransformation enzyme glutathione-S-transferase (GST) in the hepatopancreas, the gills and muscle of Spiny cheek crayfish (Orconectes limosus) from the River Danube and to compare tissue specificities of investigated enzymes. Our results indicated that both specific and total SOD activities in the hepatopancreas were lower compared to the gills and muscle. Total SOD activity in the gills was lower with respect to that in muscle. CAT and GSH-Px (both specific and total) activities were higher in the hepatopancreas compared to those in the gills and muscle. In the gills the specific and total GR activities were higher than in the hepatopancreas and muscle. The specific and total GST activities were higher in the hepatopancreas compared with the gills and muscle. Our study represents the first comprehensive report of AD enzymes in tissues of O. limosus caught in the River Danube. The noted tissue distributions of the investigated AD enzyme activities most likely reflected different metabolic activities and different responses to environmental conditions in the examined tissues. 相似文献
70.
We report the integration of a type II restriction-methylase, mFokI, into the tobacco chloroplast genome and we demonstrate that the introduced enzyme effectively directs the methylation of its target sequence in vivo and does not affect maternal inheritance. We further report the transformation of tobacco with an E. coli dcm methylase targeted to plastids and we demonstrate efficient cytosine methylation of the plastid genome. Both adenosine methylation of FokI sites and cytosine methylation of dcm sites appeared phenotypically neutral. The ability to tolerate such plastid genome methylation is a pre-requisite for a proposed plant transgene containment system. In such a system, a chloroplast located, maternally inherited restriction methylase would provide protection from a nuclear-encoded, plastid targeted restriction endonuclease. As plastids are not paternally inherited in most crop species, pollen from such plants would carry the endonuclease transgene but not the corresponding methylase; the consequence of this should be containment of all nuclear transgenes, as pollination will only be viable in crosses to the appropriate transplastomic maternal background. 相似文献