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131.
Latif N Sarathchandra P Taylor PM Antoniw J Brand N Yacoub MH 《Cell biochemistry and biophysics》2006,45(3):255-264
Cell-cell interactions and adhesion determine cellular architectural organization, proliferation, signaling, differentiation,
and death. We have identified the molecular components of different cell-cell junctions in human valve interstitial cells
(ICs) both in situ and in culture. ICs were isolated, cultured, and phenotyped for cell surface and cytoplasmic markers by flow cytometry and
immunocytochemistry. Western blotting was used to identify and quantify the molecular components of these cell-cell junctions
in human valve ICs and compared with expression in smooth muscle and fibroblast cell types. N-cadherin and desmoglein were
weakly detected on a low percentage of ICs, and the other classical cadherins were not detected. α- and β-catenin, but not
γ-catenin, were expressed at equivalent levels by all valve ICs. Valve ICs did not express connexin-32 and-40; however, connexin-26
and-43 were equally expressed by a low percentage of ICs, demonstrating cell surface and cytoplasmic expression, and connexin-45
was weakly expressed. The other cell types also expressed N-cadherin, α- and β-catenin, desmoglein and connexin-43. The expression
of these junctional molecules was predominantly by valve ICs on the inflow side of the valves. Human valve ICs have the ability
to communicate with other valve ICs and mediate cell-cell adhesion via N-cadherin, connexin-26 and-43, and desmoglein. The
junctions between valve ICs could support an interconnecting and coordinated cellular unit capable of controlling the functionality
of the valve. 相似文献
132.
María Hernndez Mesa Jonas van den Brink William E. Louch Kimberly J. McCabe Padmini Rangamani 《PLoS computational biology》2022,18(6)
Super-resolution imaging techniques have provided a better understanding of the relationship between the nanoscale organization and function of ryanodine receptors (RyRs) in cardiomyocytes. Recent data have indicated that this relationship is disrupted in heart failure (HF), as RyRs are dispersed into smaller and more numerous clusters. However, RyRs are also hyperphosphorylated in this condition, and this is reported to occur preferentially within the cluster centre. Thus, the combined impact of RyR relocalization and sensitization on Ca2+ spark generation in failing cardiomyocytes is likely complex and these observations suggest that both the nanoscale organization of RyRs and the pattern of phosphorylated RyRs within clusters could be critical determinants of Ca2+ spark dynamics. To test this hypothesis, we used computational modeling to quantify the relationships between RyR cluster geometry, phosphorylation patterns, and sarcoplasmic reticulum (SR) Ca2+ release. We found that RyR cluster disruption results in a decrease in spark fidelity and longer sparks with a lower amplitude. Phosphorylation of some RyRs within the cluster can play a compensatory role, recovering healthy spark dynamics. Interestingly, our model predicts that such compensation is critically dependent on the phosphorylation pattern, as phosphorylation localized within the cluster center resulted in longer Ca2+ sparks and higher spark fidelity compared to a uniformly distributed phosphorylation pattern. Our results strongly suggest that both the phosphorylation pattern and nanoscale RyR reorganization are critical determinants of Ca2+ dynamics in HF. 相似文献
133.
Macrophages from lepromatous leprosy patients showed poor adherence toMycobacterium leprae. The phagocytic activity of the macrophages was not correlated to the influence on the adherence ability. Based on the phagocytic
behaviour of macrophages from normal individuals and from lepromatous leprosy, patients as well as the action of neuraminidase
in reversing the extent of adherence, it is suggested that macrophages from lepromatous leprosy patients differ from those
from normal individuals in regard to their surface properties. There was no relationship between the degree of adherence and
the concentration of Fc receptors of the macrophages. It was also shown that an extract of lysed macrophages from lepromatous
leprosy patient was able to reduce the adherence ofMycobacterium leprae to normal macrophages. This study shows that adherence is a good indicator of the surface property of macrophages which in
turn could play an important role in the cell mediated immunity of the patient. The observations suggest altered macrophage
membrane structure in the long term-treated, otherwise normal, lepromatous leprosy patients. 相似文献
134.
135.
Activities of cytidine 5′-diphosphate-choline glycerol choline phosphotransferase and uridine 5′-diphosphate galactose-ceramide
galactosyltransferase were determined in isolated myelin in different brain regions of control, and rats with restricted food
intake. Kinetic experiments indicated an increase inK
m value of phosphocholinetransferase in brain stem of undernourished rats, without significant change in the specific activity
of this enzyme. Stimulation of this myelin bound enzyme activity was also evident in the animals when myelin was treated with
the detergent: Tween CF. 54. Though specific activities of galactosyl transferase in myelin of undernourished rats were significantly
diminished, theK
m of this enzyme was unaltered. These studies point to an adverse effect of early nutritional stress on the activities of enzymes
bound to myelin membrane which has hitherto been considered metabolically inert. 相似文献
136.
137.
Nitrification activities and the changes in the populations of nitrifying bacteria in soil perfused at two different H-ion concentrations 总被引:1,自引:0,他引:1
S. U. Sarathchandra 《Plant and Soil》1978,50(1-3):99-111
Summary The rate of nitrification by soil aggregates at pH 5.5 and 7.5 was examined by a perfusion technique. Nitrification occurred
at both levels of H-ion concentration but at the higher pH the rate of nitrification was greater. The population estimates
of nitrifying bacteria were correspondingly greater at the high pH. Once the pH was lowered from 7.5 to 5.5, the nitrification
rate decreased slowly with a corresponding decrease in the numbers of nitrifying bacteria. The distribution of nitrifying
bacteria throughout soil aggregates was homogenous. The lower limit of pH for nitrification was 4.3. 相似文献
138.
Catherine M. Dreiza Padmini Komalavilas Elizabeth J. Furnish Charles R. Flynn Michael R. Sheller Christopher C. Smoke Luciana B. Lopes Colleen M. Brophy 《Cell stress & chaperones》2010,15(1):1-11
The small heat shock protein, HSPB6, is a 17-kDa protein that belongs to the small heat shock protein family. HSPB6 was identified
in the mid-1990s when it was recognized as a by-product of the purification of HSPB1 and HSPB5. HSPB6 is highly and constitutively
expressed in smooth, cardiac, and skeletal muscle and plays a role in muscle function. This review will focus on the physiologic
and biochemical properties of HSPB6 in smooth, cardiac, and skeletal muscle; the putative mechanisms of action; and therapeutic
implications. 相似文献
139.
Lavanya Raja Srinivasadesikan Venkatesan Ming-Chang Lin Padmini Vediappen 《Luminescence》2023,38(3):224-231
An economical and green approach to the synthesis of naphthyl derivative for detection of l -carnitine (3-hydroxy-4-N-trimethyl-aminobutyrate) is practically important. We developed a naphthyl derivative as a probe showing ‘turn-on’ response towards l -carnitine selectively at pH 7.2 through ICT mechanism with a good limit of detection (LOD) of 0.126 μM. Using Job's plot for determining the binding stoichiometry, it was found that probe could form a more stable complex (1:1) with carnitine. The binding constant (K) between probe and carnitine was calculated as 8 × 107 M−1 using the Benesi–Hildebrand plot. The binding interaction of the probe with l -carnitine was confirmed by nuclear magnetic resonance titrations, Fourier-transform infrared spectroscopy, photo physical studies and density functional theory calculations. Meanwhile, the probe can be used to quantitatively detect carnitine in food samples. 相似文献
140.
Padmini Dalpadado 《Polar Biology》2002,25(9):656-666
Amphipods from the central and northern areas of the Barents Sea were studied by a series of MOCNESS profiles between 1990 and 1997. Themisto abyssorum, though dominant in warmer Atlantic water, was also present in Arctic water. In contrast, T. libellula was a typical Arctic species and penetrated very little into the Atlantic water masses. T. compressa was seldom found in the studied area. Linear regression analysis showed a statistically significant negative relationship between abundance of T. libellula and the variability in the Atlantic inflow. The abundance of this species seems to be, to a large extent, determined by the amount of Arctic water in the Barents Sea. The sub-Arctic species, T. abyssorum, only has a 1-year life-cycle, with the peak in release of young (2-3 mm) occurring in May and June. A few individuals may survive to be older. The Arctic species, T. libellula, seems to release the young earlier and the length-frequency distributions seem to indicate a 2-year life-span. The spring phytoplankton, which usually blooms during April in the Barents Sea, followed by high abundance of Calanus spp. and krill species, are regarded as important factors that influence the release of the amphipods' young. 相似文献