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1.
Devin Anne Espié Pascal Guérin Bernard Rigoulet Michel 《Molecular and cellular biochemistry》1998,184(1-2):107-121
Cell swelling is now admitted as being a new principle of metabolic control but little is known about the energetics of cell swelling. We have studied the influence of hypo- or hyperosmolarity on both isolated hepatocytes and isolated rat liver mitochondria. Cytosolic hypoosmolarity on isolated hepatocytes induces an increase in matricial volume and does not affect the myxothiazol sensitive respiratory rate while the absolute value of the overall thermodynamic driving force over the electron transport chain increases. This points to an increase in kinetic control upstream the respiratory chain when cytosolic osmolarity is decreased. On isolated rat liver mitochondria incubated in hypoosmotic potassium chloride media, energetic parameters vary as in cells and oxidative phosphorylation efficiency is not affected. Cytosolic hyperosmolarity induced by sodium co-transported amino acids, per se, does not affect either matrix volume or energetic parameters. This is not the case in isolated rat liver mitochondria incubated in sucrose hyperosmotic medium. Indeed, in this medium, adenine nucleotide carrier is inhibited as the external osmolarity increases, which lowers the state 3 respiration close to state 4 level and consequently leads to a decrease in oxidative phosphorylation efficiency. When isolated rat liver mitochondria are incubated in KCl hyperosmotic medium, state 3 respiratory rate, matrix volume and membrane electrical potential vary as a function of time. Indeed, matrix volume is recovered in hyperosmotic KCl medium and this recovery is dependent on Pi-Kentry. State 3 respiratory rate increases and membrane electrical potential difference decreases during the first minutes of mitochondrial incubation until the attainment of the same value as in isoosmotic medium. This shows that matrix volume, flux and force are regulated as a function of time in KCl hyperosmotic medium. Under steady state, neither matrix volume nor energetic parameters are affected. Moreover, NaCl hyperosmotic medium allows matrix volume recovery but induces a decrease in state 3 respiratory flux. This indicates that potassium is necessary for both matrix volume and flux recovery in isolated mitochondria. We conclude that hypoosmotic medium induces an increase in kinetic control both upstream and on the respiratory chain and changes the oxidative phosphorylation response to forces. At steady state, hyperosmolarity, per se, has no effect on oxidative phosphorylation in either isolated hepatocytes or isolated mitochondria incubated in KCl medium. Therefore, potassium plays a key role in matrix volume, flux and force regulation. 相似文献
2.
Francesca Passaretta Domenico Bosco Lucia Centurione Maria Antonietta Centurione Fabio Marongiu Roberta Di Pietro 《Journal of cellular and molecular medicine》2020,24(7):4350-4355
Human Amniotic Epithelial Cells (hAEC) isolated from term placenta are a promising source for regenerative medicine. However, it has long been debated whether the hAEC population consists of heterogeneous or homogeneous cells. In a previous study, we investigated the characteristics of hAEC isolated from four different regions of the amniotic membrane finding significant heterogeneity. The aim of this study was to evaluate the hepatic differentiation capability of hAEC isolated from these four regions. Human term placentae were collected after caesarean section and hAEC were isolated from four regions of the amniotic membrane (R1-R4, according to their relative distance from the umbilical cord) and treated in hepatic differentiation conditions for 14 days. hAEC-derived hepatocyte-like cells showed marked differences in the expression of hepatic markers: R4 showed higher levels of Albumin and Hepatocyte Nuclear Factor (HNF) 4α whereas R1 expressed higher Cytochrome P450 enzymes, both at the gene and protein level. These preliminary results suggest that hAEC isolated from R1 and R4 of the amniotic membrane are more prone to hepatic differentiation. Therefore, the use of hAEC from a specific region of the amniotic membrane should be taken into consideration as it could have an impact on the outcome of therapeutic applications. 相似文献
3.
Ronald T. Riley Douglas E. Goeger William P. Norred Richard J. Cole Joe W. Dorner 《Journal of biochemical and molecular toxicology》1987,2(3):251-264
In a previous study (1) we demonstrated that increased tetraphenylphosphonium (TPP) uptake by renal epithelial cells (LLC-PK1) exposed to the fungal metabolite cyclopiazonic acid (CPA) was not a result of hyperpolarization across the plasma membrane even though CPA-potentiated TPP uptake could be totally inhibited by the depolarizing agent carbonylcyanide-m-chlorophenylhydrazone (CCCP). We now demonstrate that CPA potentiates TPP accumulation by proliferating skeletal muscle (L6) and LLC-PK1 cells but not by nonproliferating primary rat hepatocytes. In LLC-PK1 cells, CPA-potentiated TPP accumulation is observed in cells at all ages. In s cells, CPA-potentiated TPP accumulation is maximal soon after subculturing, and as the cells age they become less sensitive to CPA until TPP accumulation by CPA-treated cells approaches that of untreated cells. The temporal change in sensitivity of L6 cells to CPA may be related to biochemical and/or metabolic changes which occur as the cells age in culture. Hepatocytes, LLC-PK1 cells, and L6 cells permeabilized by freeze-thaw lysis, all exhibit CPA-potentiated TPP partitioning, even in the presence of CCCP. This result indicates that both TPP and CPA must have access to the intracellular space in order for potentiated TPP partitioning to be observed. We hypothesize that the site of interaction between CPA and TPP is intracellular and probably associated with the cytoplasmic side of the plasma membrane and possibly the mitochondria. 相似文献
4.
Michael C. Mullenix Pravin T. P. Kaumaya Richard F. Mortensen 《Journal of cellular biochemistry》1994,54(3):343-353
Human C-reactive protein (CRP) is an acute phase blood component that accumulates at sites of tissue damage and necrosis and is degraded by neutrophils to biologically active peptides. A dodecapeptide composed of amino acids 27–38 of CRP mediates cell attachment in vitro. This peptide was designated the cell-binding peptide (CB-Pep) of CRP. Characterization of the interaction between fibroblasts and modified synthetic peptides with sequential deletions from either the N-terminus or C-terminus revealed that the minimal sequence for cell attachment or inhibition of cell attachment to the CB-Pep was Phe-Thr-Val-Cys-Leu , which corresponds to residues 33–37 within each of the five 206 amino acid subunits of CRP. The pentapeptide by itself mediated cell attachment. Substitutions for each residue within the CB-Pep indicated that the critical residues for activity were Phe-33 and Thr-34. This cell-binding pentapeptide represents a recognition motif for cell adhesion not found in other proteins. 相似文献
5.
《Bioscience, biotechnology, and biochemistry》2013,77(1):218-221
An easy method for primary culture of chicken hepatocytes was developed to study the influence of dioxin on birds. Chicken hepatocytes could maintain gene expression and protein secretion of albumin for a long period in serum-free medium with free atmosphere exchange at 37°C. Moreover, the cells showed a sensitive response to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by monitoring the expression of P450 1A, theta GST (θ-GST) and albumin genes. 相似文献
6.
Anna Sterniczuk Elbieta I. Waajtys-Rode Anna B. Wojtczak 《Cell biochemistry and function》1991,9(1):13-21
The flux through branched-chain alpha-ketoacid dehydrogenase and the activity of the branched-chain alpha-ketoacid dehydrogenase complex were measured in hepatocytes isolated from fed, starved and alloxan diabetic rats. The highest rate of branched-chain alpha-ketoacid oxidation was found in hepatocytes isolated from starved rats, slightly lower in those from fed rats, and significantly lower in diabetic hepatocytes. The amount of the active form of branched-chain alpha-ketoacid dehydrogenase was only slightly diminished in diabetic hepatocytes, whereas the flux through the dehydrogenase was inversely correlated with the rate of endogenous ketogenesis. The same was observed in hepatocytes isolated from starved rats when branched-chain alpha-ketoacid oxidation was measured in the presence of added oleate. In both cases the diminished flux through the dehydrogenase, restored by a short preincubation of hepatocytes with insulin, was paralleled by a decrease of fatty acid-derived ketogenesis. The significance of these findings is discussed in relation to the role of insulin in branched-chain alpha-ketoacid oxidation in liver of diabetic rats. 相似文献
7.
Hormonal modulation of hepatic plasma membrane lactate transport was studied in primary cultures of isolated hepatocytes from fed rats to examine the mechanism for the known enhancement of lactate transport in starvation and diabetes. Total cellular lactate entry was increased by 14% in the presence of dexamethasone; this was accounted for by an approximately 40% increase in the carrier-mediated component of entry with no effect on diffusion. A trend of similar magnitude was evident with glucagon. The effects of dexamethasone and glucagon on lactate transport constitute an additional potential mechanism for enhancement of gluconeogenesis by these hormones. 相似文献
8.
Anabel Fernndez‐Iglesias Martí Ortega‐Ribera Sergi Guix‐Muntet Jordi Gracia‐Sancho 《Journal of cellular and molecular medicine》2019,23(2):877-886
Liver cells isolated from pre‐clinical models are essential tools for studying liver (patho)physiology, and also for screening new therapeutic options. We aimed at developing a new antibody‐free isolation method able to obtain the four main hepatic cell types (hepatocytes, liver sinusoidal endothelial cells [LSEC], hepatic macrophages [HMΦ] and hepatic stellate cells [HSC]) from a single rat liver. Control and cirrhotic (CCl4 and TAA) rat livers (n = 6) were perfused, digested with collagenase and mechanically disaggregated obtaining a multicellular suspension. Hepatocytes were purified by low revolution centrifugations while non‐parenchymal cells were subjected to differential centrifugation. Two different fractions were obtained: HSC and mixed LSEC + HMΦ. Further LSEC and HMΦ enrichment was achieved by selective adherence time to collagen‐coated substrates. Isolated cells showed high viability (80%‐95%) and purity (>95%) and were characterized as functional: hepatocytes synthetized albumin and urea, LSEC maintained endocytic capacity and in vivo fenestrae distribution, HMΦ increased expression of inflammatory markers in response to LPS and HSC were activated upon in vitro culture. The 4 in 1 protocol allows the simultaneous isolation of highly pure and functional hepatic cell sub‐populations from control or cirrhotic single livers without antibody selection. 相似文献
9.
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