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91.
Piero L. Ipata Rossana Pesi 《Metabolomics : Official journal of the Metabolomic Society》2018,14(4):42
Background
A substrate cycle is a metabolic transformation in which a substrate A is phosphorylated to A?P at the expense of ATP (or another “high energy” compound), and A?P is converted back to A by a nucleotidase or a phosphatase. Many biochemists resisted the idea of such an ATP waste. Why a non-phosphorylated metabolite should be converted into a phosphorylated form, and converted back to its non-phosphorylated form through a “futile cycle”?Aim of review
In this Review we aim at presenting our present knowledge on the biochemical features underlying the interrelation between the muscle purine nucleotide cycle and the oxypurine cycle, and on the metabolic responses of the two cycles to increasing intensities of muscle contraction.Key scientific concepts of review
Nowadays it is widely accepted that the substrate cycles regulate many vital functions depending on the expense of large amounts of ATP, including skeletal muscle contraction, so that the expense of some extra ATP and “high energy” compounds, such as GTP and PRPP via substrate cycles, is not surprising. The Review emphasizes the strict metabolic interrelationship between the purine nucleotide cycle and the oxipurine cycle.92.
Rossana de Aguiar Cordeiro Ewerton Weslley Caracas Cedro Ana Raquel Colares Andrade Rosana Serpa Antonio José de Jesus Evangelista Jonathas Sales de Oliveira 《Biofouling》2018,34(3):309-319
The present study aimed to investigate the inhibitory effect of a bacterial biosurfactant (TIM96) on clinical strains of Trichosporon. Additionally, the effect of TIM96 on the ergosterol content, cell membrane integrity, and the hydrophobicity of planktonic cells was assessed. The inhibitory activity of TIM96 against Trichosporon biofilms was evaluated by analyzing metabolic activity, biomass and morphology. MIC values ranged from 78.125 to 312.5 μg ml?1 for TIM96; time-kill curves revealed that the decline in the number of fungal cells started after incubation for 6 h with TIM96 at both MIC and 2×MIC. The biosurfactant reduced the cellular ergosterol content and altered the membrane permeability and the surface hydrophobicity of planktonic cells. Incubation at 10×MIC TIM96 reduced cell adhesion by up to 96.89%, thus interfering with biofilm formation. This concentration also caused up to a 99.2% reduction in the metabolic activity of mature biofilms. The results indicate potential perspectives for the development of new antifungal strategies. 相似文献
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95.
Daniela Cabibi Everly Conway de Macario Sabrina Ingrao Rossana Porcasi Francesco Zucco Alberto J. L. Macario Francesco Cappello Francesca Rappa 《Cell stress & chaperones》2016,21(1):131-137
CD1a is involved in presentation to the immune system of lipid antigen derived from tumor cells with subsequent T cell activation. Hsp60 is a molecular chaperone implicated in carcinogenesis by, for instance, modulating the immune reaction against the tumor. We have previously postulated a synergism between CD1a and Hsp60 as a key factor in the activation of an effective antitumor immune response in squamous epithelia. Keratoacantomas (KAs) are benign tumors that however can transform into squamous cell carcinomas (SCCs), but the reasons for this malignization are unknown. In a previous study, we found that CD1a-positive cells are significantly more numerous in KA than in SCC. In this study, we analyzed a series of KAs and SCCs by immunohistochemistry for CD1a and Hsp60. Our results show that the levels of both are significantly lower in KA than in SCC and support the hypothesis that KA may evolve towards SCC if there is a failure of the local modulation of the antitumor immune response. The data also show that immunohistochemistry for CD1a and Hsp60 can be of help in differential diagnosis between KAs and well-differentiated forms of SCC. 相似文献
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97.
F1FO ATP Synthase Is Expressed at the Surface of Embryonic Rat Heart‐Derived H9c2 Cells and Is Affected by Cardiac‐Like Differentiation
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Marina Comelli Rossana Domenis Alessia Buso Irene Mavelli 《Journal of cellular biochemistry》2016,117(2):470-482
Taking advantage from the peculiar features of the embryonic rat heart‐derived myoblast cell line H9c2, the present study is the first to provide evidence for the expression of F1FO ATP synthase and of ATPase Inhibitory Factor 1 (IF1) on the surface of cells of cardiac origin, together documenting that they were affected through cardiac‐like differentiation. Subunits of both the catalytic F1 sector of the complex (ATP synthase‐β) and of the peripheral stalk, responsible for the correct F1‐FO assembly/coupling, (OSCP, b, F6) were detected by immunofluorescence, together with IF1. The expression of ATP synthase‐β, ATP synthase‐b and F6 were similar for parental and differentiated H9c2, while the levels of OSCP increased noticeably in differentiated cells, where the results of in situ Proximity Ligation Assay were consistent with OSCP interaction within ecto‐F1FO complexes. An opposite trend was shown by IF1 whose ectopic expression appeared greater in the parental H9c2. Here, evidence for the IF1 interaction with ecto‐F1FO complexes was provided. Functional analyses corroborate both sets of data. i) An F1FO ATP synthase contribution to the exATP production by differentiated cells suggests an augmented expression of holo‐F1FO ATP synthase on plasma membrane, in line with the increase of OSCP expression and interaction considered as a requirement for favoring the F1‐FO coupling. ii) The absence of exATP generation by the enzyme, and the finding that exATP hydrolysis was largely oligomycin‐insensitive, are in line in parental cells with the deficit of OSCP and suggest the occurrence of sub‐assemblies together evoking more regulation by IF1. J. Cell. Biochem. 9999: 1–13, 2015. © 2015 Wiley Periodicals, Inc. J. Cell. Biochem. 117: 470–482, 2016. © 2015 Wiley Periodicals, Inc. 相似文献
98.
Rossana Sidari 《Marine Biology Research》2016,12(2):193-199
To improve the study of mixed microalgal populations, three naturally evolved marine microalgal cultures were subjected to a light crushing mechanical treatment using a silicon spatula coupled with zymolyase treatment at four concentrations: 5, 10, 20 and 25 U/ml, for 15, 30, 45 and 60 min before being observed under a microscope. The enzyme concentration of 20 U/ml after 45 min reduces the size of macroscopic microalgal aggregates and improves the microscopic observation of the different microalgal species comprising the population. There was no improvement using the higher enzyme concentration. This paper proposes a new approach to the study of naturally evolved microalgal populations which is useful for distinguishing the morphology of the different species present in the population and allowing for the identification by classical keys, and also to obtain a pure culture from an inoculum of mixed species by using a micromanipulator for cell counting. 相似文献
99.
Sequence of a cDNA for mouse thymidylate synthase reveals striking similarity with the prokaryotic enzyme 总被引:11,自引:0,他引:11
Perryman SM; Rossana C; Deng TL; Vanin EF; Johnson LF 《Molecular biology and evolution》1986,3(4):313-321
We report the nucleotide sequence of a cloned cDNA, pMTS-3, that contains a
1-kb insert corresponding to mouse thymidylate synthase (E.C. 2.1.1.45).
The open reading frame of 921 nucleotides from the first AUG to the
termination codon specifies a protein with a molecular mass of 34,962
daltons. The predicted amino acid sequence is 90% identical with that of
the human enzyme. The mouse sequence also has an extremely high degree of
similarity (as much as 55% identity) with prokaryotic thymidylate synthase
sequences, indicating that thymidylate synthase is among the most highly
conserved proteins studied to date. The similarity is especially pronounced
(as much as 80% identity) in the 44-amino-acid region encompassing the
binding site for deoxyuridylic acid. The cDNA sequence also suggests that
mouse thymidylate synthase mRNA lacks a 3' untranslated region, since the
termination codon, UAA, is followed immediately by a poly(A) segment.
相似文献
100.
Selected lactic acid bacteria synthesize antioxidant peptides during sourdough fermentation of cereal flours 总被引:1,自引:0,他引:1
A pool of selected lactic acid bacteria was used for the sourdough fermentation of various cereal flours with the aim of synthesizing antioxidant peptides. The radical-scavenging activity of water/salt-soluble extracts (WSE) from sourdoughs was significantly (P < 0.05) higher than that of chemically acidified doughs. The highest activity was found for whole wheat, spelt, rye, and kamut sourdoughs. Almost the same results were found for the inhibition of linoleic acid autoxidation. WSE were subjected to reverse-phase fast protein liquid chromatography. Thirty-seven fractions were collected and assayed in vitro. The most active fractions were resistant to further hydrolysis by digestive enzymes. Twenty-five peptides of 8 to 57 amino acid residues were identified by nano-liquid chromatography-electrospray ionization-tandem mass spectrometry. Almost all of the sequences shared compositional features which are typical of antioxidant peptides. All of the purified fractions showed ex vivo antioxidant activity on mouse fibroblasts artificially subjected to oxidative stress. This study demonstrates the capacity of sourdough lactic acid bacteria to release peptides with antioxidant activity through the proteolysis of native cereal proteins. 相似文献