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51.
Functional changes in human leukemic cell line HL-60. A model for myeloid differentiation 总被引:12,自引:0,他引:12 下载免费PDF全文
Polar solvents induce terminal differentiation in the human promyelocytic leukemia cell line HL-60. The present studies describe the functional changes that accompany the morphologic progression from promyelocytes to bands and poly-morphonuclear leukocytes (PMN) over 9 d of culture in 1.3 percent dimethylsulfoxide (DMSO). As the HL-60 cells mature, the rate of O(2-) production increase 18-fold, with a progressive shortening of the lag time required for activation. Hexosemonophosphate shunt activity rises concomitantly. Ingestin of paraffin oil droplets opsonized with complement or Ig increases 10-fold over 9 d in DMSO. Latex ingestion per cell by each morphologic type does not change significantly, but total latex ingestion by groups of cells increases with the rise in the proportion of mature cells with greater ingestion capacities. Degranulation, as measured by release of β-glucuronidase, lysozyme, and peroxidase, reaches maximum after 3-6 d in DMSO, then declines. HL-60 cells contain no detectable lactoferrin, suggesting that their secondary granules are absent or defective. However, they kill staphylococci by day 6 in DMSO. Morphologically immature cells (days 1-3 in DMSO) are capable of O(2-) generation, hexosemonophosphate shunt activity, ingestion, degranulation, and bacterial killing. Maximal performance of each function by cells incubated in DMSO for longer periods of time is 50-100 percent that of normal PMN. DMSO- induced differentiation of HL-60 cells is a promising model for myeloid development. 相似文献
52.
Limulus ventral photoreceptors were voltage clamped to the resting (dark) potential and stimulated by a 20-ms test flash and a 1-s conditioning flash. At a constant level of adaptation, we measured the response to the test flash given in the dark (control) and the incremental response produced when the test flash occurred within the duration of the conditioning flash. The incremental response is defined as the response to the conditioning and test flashes minus the response to the conditioning flash given alone. When the test flash was presented within 100 ms after the onset of the conditioning flash we observed that: (a) for dim conditioning flashes the incremental response equaled the control response; (b) for intermediate intensity conditioning flashes the incremental response was greater than the control response (we refer to this as enhancement); (c) for high intensity conditioning flashes the incremental response nearly equaled the control response. Using 10-μm diam spots of illumnination, we stimulated two spatially separate regions of one photoreceptor. When the test flash and the conditioning flash were presented to the same region, enhancement was present; but when the flashes were applied to separate regions, enhancement was nearly absent. This result indicates that enhancement is localized to the region of illumination. We discuss mechanisms that may account for enhancement. 相似文献
53.
Qi-An Sun Benlian Wang Masaru Miyagi Douglas T. Hess Jonathan S. Stamler 《The Journal of biological chemistry》2013,288(32):22961-22971
In mammalian skeletal muscle, Ca2+ release from the sarcoplasmic reticulum (SR) through the ryanodine receptor/Ca2+-release channel RyR1 can be enhanced by S-oxidation or S-nitrosylation of separate Cys residues, which are allosterically linked. S-Oxidation of RyR1 is coupled to muscle oxygen tension (pO2) through O2-dependent production of hydrogen peroxide by SR-resident NADPH oxidase 4. In isolated SR (SR vesicles), an average of six to eight Cys thiols/RyR1 monomer are reversibly oxidized at high (21% O2) versus low pO2 (1% O2), but their identity among the 100 Cys residues/RyR1 monomer is unknown. Here we use isotope-coded affinity tag labeling and mass spectrometry (yielding 93% coverage of RyR1 Cys residues) to identify 13 Cys residues subject to pO2-coupled S-oxidation in SR vesicles. Eight additional Cys residues are oxidized at high versus low pO2 only when NADPH levels are supplemented to enhance NADPH oxidase 4 activity. pO2-sensitive Cys residues were largely non-overlapping with those identified previously as hyperreactive by administration of exogenous reagents (three of 21) or as S-nitrosylated. Cys residues subject to pO2-coupled oxidation are distributed widely within the cytoplasmic domain of RyR1 in multiple functional domains implicated in RyR1 activity-regulating interactions with the L-type Ca2+ channel (dihydropyridine receptor) and FK506-binding protein 12 as well as in “hot spot” regions containing sites of mutation implicated in malignant hyperthermia and central core disease. pO2-coupled disulfide formation was identified, whereas neither S-glutathionylated nor sulfenamide-modified Cys residues were observed. Thus, physiological redox regulation of RyR1 by endogenously generated hydrogen peroxide is exerted through dynamic disulfide formation involving multiple Cys residues. 相似文献
54.
55.
The mechanism of thionitrite decomposition, both in vivo and in vitro, remains unclear. Thionitrite stability is highly variable; it is a complex function of thionitrite structure and environmental condition. Several recent advances clarify the role of unimolecular homlytic decomposition, metal-catalyzed reductive decomposition and higher-order enzymatic and non-enzymatic processes to the overall observed stability of thionitrites. 相似文献
56.
C Bussadori A Moreo M Di Donato B De Chiara D Negura E Dall'Aglio E Lobiati M Chessa C Arcidiacono JS Dua F Mauri M Carminati 《Cardiovascular ultrasound》2009,7(1):1-11
Background
Cardiac time intervals have been described as a measure of cardiac performance, where prolongation, shortening and delay of the different time intervals have been evaluated as markers of cardiac dysfunction. A relatively recently developed method with improved ability to measure cardiac events is Tissue Doppler Imaging (TDI), allowing accurate measurement of myocardial movements.Methods
We propose the state diagram of the heart as a new visualization tool for cardiac time intervals, presenting comparative, normalized data of systolic and diastolic performance, providing a more complete overview of cardiac function. This study aimed to test the feasibility of the state diagram method by presenting examples demonstrating its potential use in the clinical setting and by performing a clinical study, which included a comparison of the state diagram method with established echocardiography methods (E/E' ratio, LVEF and WMSI). The population in the clinical study consisted of seven patients with non ST-elevation myocardial infarction (NSTEMI) and seven control subjects, individually matched according to age and gender. The state diagram of the heart was generated from TDI curves from seven positions in the myocardium, visualizing the inter- and intraventricular function of the heart by displaying the cardiac phases.Results
The clinical examples demonstrated that the state diagram allows for an intuitive visualization of pathological patterns as ischemia and dyssynchrony. Further, significant differences in percentage duration between the control group and the NSTEMI group were found in eight of the totally twenty phases (10 phases for each ventricle), e.g. in the transition phases (Pre-Ejection and Post-Ejection). These phases were significantly longer (> 2.18%) for the NSTEMI group than for the control group (p < 0.05). No significant differences between the groups were found for the established echocardiography methods.Conclusion
The test results clearly indicate that the state diagram has potential to be an efficient tool for visualization of cardiac dysfunction and for detection of NSTEMI. 相似文献57.
58.
Tiago JS Lopes Tatyana Luganskaja Maja Vujić Spasić Matthias W Hentze Martina U Muckenthaler Klaus Schümann Jens G Reich 《BMC systems biology》2010,4(1):112
Background
Every cell of the mammalian organism needs iron as trace element in numerous oxido-reductive processes as well as for transport and storage of oxygen. The very versatility of ionic iron makes it a toxic entity which can catalyze the production of radicals that damage vital membranous and macromolecular assemblies in the cell. The mammalian organism maintains therefore a complex regulatory network of iron uptake, excretion and intra-body distribution. Intracellular regulation in different cell types is intertwined with a global hormonal signalling structure. Iron deficiency as well as excess of iron are frequent and serious human disorders. They can affect every cell, but also the organism as a whole. 相似文献59.
Arlene L. Hankinson Martha L. Daviglus Linda Van Horn Queenie Chan Ian Brown Elaine Holmes Paul Elliott Jeremiah Stamler 《Obesity (Silver Spring, Md.)》2013,21(3):637-643
Objective:
Obesity often clusters with other major cardiovascular disease risk factors, yet a subset of the obese appears to be protected from these risks. Two obesity phenotypes are described, (i) “metabolically healthy” obese, broadly defined as body mass index (BMI) ≥ 30 kg/m2 and favorable levels of blood pressure, lipids, and glucose; and (ii) “at risk” obese, BMI ≥ 30 with unfavorable levels of these risk factors. More than 30% of obese American adults are metabolically healthy. Diet and activity determinants of obesity phenotypes are unclear. We hypothesized that metabolically healthy obese have more favorable behavioral factors, including less adverse diet composition and higher activity levels than at risk obese in the multi‐ethnic group of 775 obese American adults ages 40‐59 years from the International Population Study on Macro/Micronutrients and Blood Pressure (INTERMAP) cohort.Design and Methods:
In gender‐stratified analyses, mean values for diet composition and activity behavior variables, adjusted for age, race, and education, were compared between metabolically healthy and at risk obese.Results:
Nearly one in five (149/775 or 19%) of obese American INTERMAP participants were classified as metabolically healthy obese. Diet composition and most activity behaviors were similar between obesity phenotypes, although metabolically healthy obese women reported higher sleep duration than at risk obese women.Conclusions:
These results do not support hypotheses that diet composition and/or physical activity account for the absence of cardiometabolic abnormalities in metabolically healthy obese. 相似文献60.
Elisabeth Jonas Peter C Thomson Evelyn JS Hall David McGill Mary K Lam Herman W Raadsma 《遗传、选种与进化》2011,43(1):22