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161.
A mouse liver genomic library screened with a full-length cDNA encoding murine ferritin heavy chain (mFHC) [Torti et al., J. Biol. Chem. 263 (1988) 12638-12644] yielded a functional genomic clone mFHC. The genomic clone isolated included a region of approximately 3 kb containing four exons and three introns. Sequence comparisons of the mouse genomic clone with other genomic clones from rat, human and chicken showed a high degree of similarity among species in the coding regions. Introns and flanking sequences were less conserved. However, comparison of mFHC promoter elements with FHC genes from other species revealed common elements. Analysis of the genomic structure of FHC suggested the presence of pseudogenes. S1 nuclease analysis, however, confirmed that this mouse clone, when transfected into human MRC-5 fibroblasts, was transcribed, indicating that this clone contains an FHC functional gene. 相似文献
162.
In rat adipocyte membranes, both beta-adrenergic agonists and beta-adrenergic antagonists competed with (--)[3H]dihydroalprenolol for high affinity (KD 2-4 nM) and low capacity binding sites. The antagonists but not the agonists competed with (--)[3H]dihydroalprenolol for lower affinity and higher capacity sites. The present studies were performed in order to characterize the adipocyte beta-adrenergic receptor and distinguish it from low affinity, higher capacity sites which were heat-labile and not stereoselective. When isoproterenol was used to define the nonspecific binding, saturation studies showed a single binding site with a capacity of approximately 100 fmol/mg membrane protein (corresponding to approximately 50,000 sites/adipocyte). Binding was saturated by 10 nM (--)[3H]dihydroalprenolol. Approximate KD's of 204 nM were observed. Kinetic analysis of (--)[3H]dihydroalprenolol binding provided an independent measurement of KD between 0.75 and 1.1 nM. This binding site had the characteristics of a beta 1-adrenergic receptor with the potency of isoproterenol greater than norepinephrine greater than or equal to epinephrine as competitors of binding. Furthermore, the KD of inhibition of (--)[3H]dihydroalprenolol binding correlated with the Ki of inhibition by antagonists or Ka of activation by agonists of glycerol release in isolated adipocytes (r = 0.968, P less than 0.001). These results suggest that beta-adrenergic agonists compete with (--)[3H]dihydroalprenolol for the high affinity binding site which represents the physiological site. Furthermore, the use of antagonists (propranolol, alprenolol) to define specific beta-binding includes nonspecific site(s) as well as the beta-adrenergic site. Previous characterization and quantitation of beta receptors in rat fat cell membranes may have been in error by incorporating both types of binding in their measurement. 相似文献
163.
CD38 is a multifunctional cell surface ectoenzyme that catalyzes both the synthesis of cyclic ADP-ribose from NAD+ and its hydrolysis to ADP-ribose. In this work, we investigated the metabolism of NADP+ by CD38 expressed on human platelets. Incubation of either platelet membranes or intact cells with NADP+ resulted in the rapid and time-dependent accumulation of ADP-ribose 2'-phosphate that paralleled the consumption of the substrate. However, under the same conditions, synthesis of cyclic ADP-ribose 2'-phosphate was not observed. By immunoprecipitation experiments, we identified CD38 as the enzyme responsible for the observed NADP+ glycohydrolase activity. The lack of detection of cyclic ADP-ribose 2'-phosphate was not due to its rapid hydrolysis, since direct incubation of platelet membranes with cyclic ADP-ribose 2'-phosphate did not result in the formation of ADP-ribose 2'-phosphate. By contrast, the same membrane samples expressed a significant ability to hydrolyze cyclic ADP-ribose to ADP-ribose. The absence of cyclic ADP-ribose 2'-phosphate hydrolase activity was also confirmed using high concentrations of substrate and by analysing both intact Jurkat T-lymphocytes and immunoprecipitated CD38. These results indicate that CD38, which is a multifunctional enzyme towards NAD+, displays exclusively a NADP+ glycohydrolase activity and is unable to catalyze both the synthesis and the hydrolysis of cyclic ADP-ribose 2'-phosphate. 相似文献
164.
Giuseppe Ramaschi Mauro Torti Fabiola Sinigaglia Cesare Balduini 《Cell biochemistry and function》1993,11(4):241-249
Stimulation of human platelets with concanavalin A resulted in a significant increase in the concentration of cytoplasmic free Ca2+. This effect was due to two different processes: Ca2+ mobilization from internal stores and Ca2+ influx from the extracellular medium. Kinetic analysis revealed that the release of Ca2+ from internal storage sites occurred sooner than the opening of plasma membrane Ca2+ channels. The ability of concanavalin A to induce a sustained increase in cytoplasmic Ca2+ concentration was antagonized and reversed by methyl ∝-D -mannopyranoside, demonstrating that it was promoted by the interaction of the lectin with cell surface glycoproteins. Succinyl–concanavalin A, a dimeric derivative of the lectin, that does not promote patching/capping of the receptor, was able to bind to the platelet surface, and antagonized the effects of native concanavalin A. In addition, succinyl–concanavalin A, per se, was unable to induce Ca2+ mobilization in human platelets. Therefore, the action of the native concanavalin A was mediated by receptor clustering events. Concanavalin A mobilized Ca2+ from the same internal stores from which Ca2+ was mobilized in response to strong platelet agonists, such as thrombin and arachidonic acid. However, while thrombin was ineffective in inducing Ca2+ release after stimulation of platelets with Con A, Con A was able to cause a full discharge of Ca2+ from internal stores even in platelets previously stimulated with thrombin. These results demonstrate for the first time that the clustering of specific membrane glycoproteins can trigger platelet activation. The physiological implications during platelet aggregation are discussed. 相似文献
165.
Alicia Arnott Darren Jardine Kim Wilson Paul R. Gorry Kate Merlin Patricia Grey Matthew G. Law Elizabeth M. Dax Anthony D. Kelleher Don E. Smith Dale A. McPhee and the Pulse Study Team 《PloS one》2010,5(9)
Several clinical studies have shown that, relative to disease progression, HIV-1 isolates that are less fit are also less pathogenic. The aim of the present study was to investigate the relationship between viral fitness and control of viral load (VL) in acute and early HIV-1 infection. Samples were obtained from subjects participating in two clinical studies. In the PULSE study, antiretroviral therapy (ART) was initiated before, or no later than six months following seroconversion. Subjects then underwent multiple structured treatment interruptions (STIs). The PHAEDRA study enrolled and monitored a cohort of individuals with documented evidence of primary infection. The subset chosen were individuals identified no later than 12 months following seroconversion to HIV-1, who were not receiving ART. The relative fitness of primary isolates obtained from study participants was investigated ex vivo. Viral DNA production was quantified using a novel real time PCR assay. Following intermittent ART, the fitness of isolates obtained from 5 of 6 PULSE subjects decreased over time. In contrast, in the absence of ART the fitness of paired isolates obtained from 7 of 9 PHAEDRA subjects increased over time. However, viral fitness did not correlate with plasma VL. Most unexpected was the high relative fitness of isolates obtained at Baseline from PULSE subjects, before initiating ART. It is widely thought that the fitness of strains present during the acute phase is low relative to strains present during chronic HIV-1 infection, due to the bottleneck imposed upon transmission. The results of this study provide evidence that the relative fitness of strains present during acute HIV-1 infection may be higher than previously thought. Furthermore, that viral fitness may represent an important clinical parameter to be considered when deciding whether to initiate ART during early HIV-1 infection. 相似文献
166.
Janjetic M Barrado A Torti H Weill R Orlandini J Urriza R Boccio J 《Biological trace element research》2006,109(2):195-200
In this research, we measured the iron bioavailability of ferrous gluconate stabilized with glycine (SFG) when it is used
to fortify petit suisse cheese using the prophylactic-preventive method in rats. Three groups of male, weaned rats received
a basal diet (control diet; 5.2 ppm Fe), a reference standard diet (SO4Fe; 9.2 ppm Fe), and a basal diet using iron-fortified petit suisse cheese as the iron source (cheese diet; 8.8 ppm Fe) for
22d. The iron bioavailability was calculated as the ratio between the mass of iron incorporated into hemoglobin and the total
iron intake per animal during the treatment. These values (BioFe) were 68% and 72% for SFG and ferrous sulfate, respectively.
The value of the Relative Biological Value (RBV) was 95% for SFG in petit suisse cheese. These results show that according
to this method, the iron bioavailability from industrial fortified petit suisse cheese can be considered as a high bioavailability
rate. 相似文献
167.
168.
Bonadonna Giovanna Zaccagno Michele Torti Valeria Valente Daria De Gregorio Chiara Randrianarison Rose Marie Tan Chia Gamba Marco Giacoma Cristina 《International journal of primatology》2020,41(2):224-245
International Journal of Primatology - Territorial pair-living species tend to occupy and defend stable areas, assumed to contain all the resources needed for the lifetime of the group.... 相似文献
169.
Tongguang Wang Elliot Choi Maria Chiara G. Monaco Emilie Campanac Marie Medynets Thao Do Prashant Rao Kory R. Johnson Abdel G. Elkahloun Gloria Von Geldern Tory Johnson Sriram Subramaniam Dax Hoffman Eugene Major Avindra Nath 《PloS one》2013,8(11)
Proinflammatory factors from activated T cells inhibit neurogenesis in adult animal brain and cultured human fetal neural stem cells (NSC). However, the role of inhibition of neurogenesis in human neuroinflammatory diseases is still uncertain because of the difficulty in obtaining adult NSC from patients. Recent developments in cell reprogramming suggest that NSC may be derived directly from adult fibroblasts. We generated NSC from adult human peripheral CD34+ cells by transfecting the cells with Sendai virus constructs containing Sox2, Oct3/4, c-Myc and Klf4. The derived NSC could be differentiated to glial cells and action potential firing neurons. Co-culturing NSC with activated autologous T cells or treatment with recombinant granzyme B caused inhibition of neurogenesis as indicated by decreased NSC proliferation and neuronal differentiation. Thus, we have established a unique autologous in vitro model to study the pathophysiology of neuroinflammatory diseases that has potential for usage in personalized medicine. 相似文献