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171.
Kerstin G?bel Stefan Bittner Manuela Cerina Alexander M. Herrmann Heinz Wiendl Sven G. Meuth 《Journal of visualized experiments : JoVE》2015,(96)
Death of oligodendrocytes accompanied by destruction of neurons and axons are typical histopathological findings in cortical and subcortical grey matter lesions in inflammatory demyelinating disorders like multiple sclerosis (MS). In these disorders, mainly CD8+ T-cells of putative specificity for myelin- and oligodendrocyte-related antigens are found, so that neuronal apoptosis in grey matter lesions may be a collateral effect of these cells. Different types of animal models are established to study the underlying mechanisms of the mentioned pathophysiological processes. However, although they mimic some aspects of MS, it is impossible to dissect the exact mechanism and time course of ‘‘collateral’’ neuronal cell death. To address this course, here we show a protocol to study the mechanisms and time response of neuronal damage following an oligodendrocyte-directed CD8+ T cell attack. To target only the myelin sheath and the oligodendrocytes, in vitro activated oligodendrocyte-specific CD8+ T-cells are transferred into acutely isolated brain slices. After a defined incubation period, myelin and neuronal damage can be analysed in different regions of interest. Potential applications and limitations of this model will be discussed. 相似文献
172.
173.
Laurent J. Catoire Manuela Zoonens Carine van Heijenoort Fabrice Giusti Éric Guittet Jean-Luc Popot 《European biophysics journal : EBJ》2010,39(4):623-630
The atomic structure of OmpX, the smallest member of the bacterial outer membrane protein family, has been previously established
by X-ray crystallography and NMR spectroscopy. In apparent conflict with electrophysiological studies, the lumen of its transmembrane
β-barrel appears too tightly packed with amino acid side chains to let any solute flow through. In the present study, high-resolution
solution NMR spectra were obtained of OmpX kept water-soluble by either amphipol A8-35 or the detergent dihexanoylphosphatidylcholine.
Hydrogen/deuterium exchange measurements performed after prolonged equilibration show that, whatever the surfactant used,
some of the amide protons of the membrane-spanning region exchange much more readily than others, which likely reflects the
dynamics of the barrel. 相似文献
174.
The kinetics of the transfer of stearic acids between human serum albumin (HSA) and long circulating sterically stabilised
liposomes (SSL) composed of dipalmitoylphosphatidylcholine (DPPC) and of submicellar content of the polymer-lipid poly(ethylene
glycol:2000)-dipalmitoylphosphatidylethanolamine (PEG:2000-DPPE) have been studied by fluorescence spectroscopy. The study
exploits the fact that HSA has a single tryptophan (Trp) residue and that the intrinsic Trp-emission intensity is quenched
by the presence of doxyl spin-labelled stearic acids (SASL). Protein/lipid dispersions are considered in which SASL molecules
are inserted either in the protein or in the SSL, and the transfer of SASL between the protein and SSL is conveniently monitored
by the time variation of the inherent Trp-fluorescence intensity of HSA. It was found that the transfer of fatty acids between
HSA and SSL depends on the type of donor and acceptor matrix, on the temperature (i.e., on the physical state of the lipid
bilayers) and on the grafting density of the PEG-lipids at the lipid/protein interface. In the absence of polymer-lipids,
the rate of transfer increases with temperature in both directions of transfer, and it is higher for the passage from DPPC
bilayers to HSA. The presence of polymer-lipids reduces the rate of transfer both in the mushroom and in the brush regime
of the polymer chains, especially at low grafting density and for lipid membranes in the fluid phase. 相似文献
175.
Antonia Nostro Roberto Scaffaro Giovanna Ginestra Manuela D’Arrigo Luigi Botta Andreana Marino Giuseppe Bisignano 《Applied microbiology and biotechnology》2010,87(2):729-737
The aim of this study was to evaluate the effect of poly-ethylene-co-vinyl acetate (EVA) films incorporating different concentrations
(0.1%, 0.5% and 1%) of nisin on the biofilm-forming ability of Listeria monocytogenes ATCC 7644, Staphylococcus aureus 815 and Staphylococcus epidermidis ATCC 35984. Nisin was incorporated into two grades of EVA (EVA14 and EVA28) in the melt during a common film-blowing operation.
The efficacy of EVA/nisin films was evaluated by biofilm biomass measurements and Live/Dead staining in combination with fluorescence
microscopy. In order to evaluate whether the nisin incorporation could modify the film surface properties, contact angle measurements
and scanning electron microscopy were performed. The results revealed the efficacy of EVA14/nisin films in reducing biofilm
formation on their surfaces with more evident effect for S. epidermidis than L. monocytogenes and S. aureus strains. In contrast, EVA28/nisin films showed unsatisfactory activity. Fluorescence microscopy confirmed poor biofilm formation
on EVA14/nisin films, also characterised by the presence of dead cells. The data presented in this study offer new potential
applications for developing strategies aimed to improve the effect of antimicrobial agents. 相似文献
176.
Manuela Gavina Lorena Za Raffaella Molteni Ruggero Pardi Ivan de Curtis 《Biology of the cell / under the auspices of the European Cell Biology Organization》2010,102(4):231-244
Background information. Cell motility entails the reorganization of the cytoskeleton and membrane trafficking for effective protrusion. The GIT–PIX protein complexes are involved in the regulation of cell motility and adhesion and in the endocytic traffic of members of the family of G‐protein‐coupled receptors. We have investigated the function of the endogenous GIT complexes in the regulation of cell motility stimulated by fMLP (formyl‐Met‐Leu‐Phe) peptide, in a rat basophilic leukaemia RBL‐2H3 cell line stably expressing an HA (haemagglutinin)‐tagged receptor for the fMLP peptide. Results. Our analysis shows that RBL cells stably transfected with the chemoattractant receptor expressed both GIT1–PIX and GIT2–PIX endogenous complexes. We have used silencing of the different members of the complex by small interfering RNAs to study the effects on a number of events linked to agonist‐induced cell migration. We found that cell adhesion was not affected by depletion of any of the proteins of the GIT complex, whereas agonist‐enhanced cell spreading was inhibited. Analysis of agonist‐stimulated haptotactic cell migration indicated a specific positive effect of GIT1 depletion on trans‐well migration. The internalization of the formyl‐peptide receptor was also inhibited by depletion of GIT1 and GIT2. The effects of the GIT complexes on trafficking of the receptors was confirmed by an antibody‐enhanced agonist‐induced internalization assay, showing that depletion of PIX, GIT1 or GIT2 protein caused decreased perinuclear accumulation of internalized receptors. Conclusions. Our results show that endogenous GIT complexes are involved in the regulation of chemoattractant‐induced cell motility and receptor trafficking, and support previous findings indicating an important function of the GIT complexes in the regulation of different G‐protein‐coupled receptors. Our results also indicate that endogenous GIT1 and GIT2 regulate distinct subsets of agonist‐induced responses and suggest a possible functional link between the control of receptor trafficking and the regulation of cell motility by GIT proteins. 相似文献
177.
Asha Nair Manuela Simonetti Elsa Fabbretti Andrea Nistri 《Cellular and molecular neurobiology》2010,30(4):505-509
Cdk5 is an endogenous kinase activated by the neuronal-specific protein p35 and implicated in multiple neuronal functions,
including modulation of certain pain responses. We investigated whether Cdk5 could regulate ATP-gated P2X3 receptors that are members of the family of membrane proteins expressed by sensory neurons to transduce nociception in baseline
and chronic pain. To study the potential P2X3 receptor modulation by Cdk5, we co-transfected rat P2X3 receptors and Cdk5 into HEK cells and observed increased P2X3 receptor serine phosphorylation together with downregulation of receptor currents only when these genes were transfected
together with the gene of the Cdk5 activator p35. The changes in receptor responses were limited to depressed current amplitude
as desensitization and recovery were not altered. Transfection of p35 with P2X3 similarly downregulated receptor responses, suggesting that this phenomenon could be observed even with constitutive Cdk5.
The present data indicate a novel target to express the action of Cdk5 on membrane proteins involved in pain perception. 相似文献
178.
Silvia Del Ry Daniela Giannessi Maristella Maltinti Manuela Cabiati Concetta Prontera Annalisa Iervasi Chiara Caselli Anna Maria Mazzone Danilo Neglia 《Cytokine》2010,49(3):325-330
In patients with dilated cardiomyopathy (DCM) abnormal myocardial blood flow (MBF) has been associated with coronary microvascular dysfunction. The aim of this study was to test the hypothesis that osteopontin (OPN) plasma levels could be associated with the activation of the renin–aldosterone system (RAS) in these patients and be involved in mediating myocardial and coronary damage. In 66 patients with idiopathic left ventricular dysfunction of variable severity the plasma levels of OPN were correlated with biomarkers of systemic metabolism, RAS activation, myocardial dysfunction and with clinical indexes of left ventricle (LV) function and perfusion obtained by 2D-echocardiography and PET. As compared to controls, patients showed a significant increase of inflammatory markers (OPN: 508 ± 30.8 ng/ml vs. 426.9 ± 16.4, p < 0.05 and interleukin (IL)-6: 1.71 ± 0.29 pg/ml vs. 0.38 ± 0.03 pg/ml, p < 0.001) and of indexes of cardiac damage. OPN levels were significantly correlated with the extent of microvascular dysfunction (MBF at rest: p = 0.01; during dipyridamole: p = 0.0003) and with plasma renin activity (PRA) (r = 0.26, p = 0.04). Both in patients with milder or more severe LV dysfunction lower MBF values were associated with higher OPN levels and PRA. These results suggest a interdependent role of RAS and vascular inflammation in cardiomyopathy. 相似文献
179.
Pierre-David Petit Manuela Pensini Joël Tessaro Claude Desnuelle Patrick Legros Serge S. Colson 《Journal of electromyography and kinesiology》2010,20(6):1186-1195
This study compared the effects of 6-week whole-body vibration (WBV) training programs with different frequency and peak-to-peak displacement settings on knee extensor muscle strength and power. The underlying mechanisms of the expected gains were also investigated. Thirty-two physically active male subjects were randomly assigned to a high-frequency/high peak-to-peak displacement group (HH; n = 12), a low-frequency/low peak-to-peak displacement group (LL; n = 10) or a sham training group (SHAM; n = 10). Maximal voluntary isometric, concentric and eccentric torque of the knee extensors, maximal voluntary isometric torque of the knee flexors, jump performance, voluntary muscle activation, and contractile properties of the knee extensors were assessed before and after the training period. Significant improvement in knee extensor eccentric voluntary torque (P < 0.01), knee flexor isometric voluntary torque (P < 0.05), and jump performance (P < 0.05) was observed only for HH group. Regardless of the group, knee extensor muscle contractile properties (P < 0.05) were enhanced. No modification was observed for voluntary muscle activation or electrical activity of agonist and antagonist muscles. We concluded that high-frequency/high peak-to-peak displacement was the most effective vibration setting to enhance knee extensor muscle strength and jump performance during a 6-week WBV training program and that these improvements were not mediated by central neural adaptations. 相似文献
180.
Andrea Bonisoli-Alquati Timothy A. Mousseau Anders Pape Møller Manuela Caprioli Nicola Saino 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2010,155(2):205-210
The Chernobyl nuclear accident produced the largest unintended release of radionuclides in history, with dramatic consequences for humans and other organisms. Exposure to ionizing radiation is known to reduce circulating and stored levels of specific antioxidants in birds and humans, thus potentially increasing oxidative stress. However, overall effects of radioactive exposure on oxidative status have never been investigated in any free ranging vertebrate. We measured plasma antioxidant capacity and concentration of reactive oxygen metabolites in adult barn swallows (Hirundo rustica) from colonies with variable background radiation levels in the Chernobyl region in Ukraine and Belarus. We predicted that antioxidants would decrease while reactive oxygen metabolites would increase with exposure to increasing levels of radiation at the breeding sites. Consistent with this expectation, radiation level positively predicted plasma concentration of reactive oxygen metabolites, whereas no significant covariation was found with non-enzymatic plasma antioxidant capacity. An index of oxidative stress was also larger in barn swallows exposed to high contamination levels. Thus, radioactive contamination appeared to be responsible for the increased generation of reactive oxygen metabolites and the imbalance between reactive oxygen metabolites and non-enzymatic plasma antioxidant capacity. 相似文献