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1.
Jolly (1982, Biometrics 38, 301-321) presented modifications of the Jolly-Seber model for capture-recapture data, which assume constant survival and/or capture rates. Where appropriate, because of the reduced number of parameters, these models lead to more efficient estimators than the Jolly-Seber model. The tests to compare models given by Jolly do not make complete use of the data, and we present here the appropriate modifications, and also indicate how to carry out goodness-of-fit tests which utilize individual capture history information. We also describe analogous models for the case where young and adult animals are tagged. The availability of computer programs to perform the analysis is noted, and examples are given using output from these programs. 相似文献
2.
Ketoacidosis affects patients who are deficient in the enzyme activity of succinyl-CoA:3-ketoacid CoA transferase (SCOT), since SCOT catalyses the activation of acetoacetate in the metabolism of ketone bodies. Thus far, structure/function analysis of the mammalian enzyme has been predicted based on the three-dimensional structure of a CoA transferase determined from an anaerobic bacterium that utilizes its enzyme for glutamate fermentation. To better interpret clinical data, we have determined the structure of a mammalian CoA transferase from pig heart by X-ray crystallography to 2.5 A resolution. Instrumental to the structure determination were selenomethionine substitution and the use of argon during purification and crystallization. Although pig heart SCOT adopts an alpha/beta protein fold, resembling the overall fold of the bacterial CoA transferase, several loops near the active site of pig heart SCOT follow different paths than the corresponding loops in the bacterial enzyme, accounting for differences in substrate specificities. Two missense mutations found associated with SCOT of ketoacidosis patients were mapped to a location in the structure that might disrupt the stabilization of the amino-terminal strand and thereby interfere with the proper folding of the protein into a functional enzyme. 相似文献
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The in vivo effect of indomethacin and prostaglandin E2 on ACTH and DBCAMP-induced steroidogenesis in hypophysectomized rats 总被引:1,自引:0,他引:1
The level of plasma corticosterone attained in hypophysectomized rats stimulated with ACTH was significantly reduced by pretreatment with indomethacin, an inhibitor of prostaglandin synthesis. This effect was not seen in animals stimulated with dibutyryl cyclic AMP. Intraperitoneal injection of prostaglandin E2 to indomethacin treated rats restored the normal response to ACTH stimulation. However, PGE2 itself did not have any significant effect on plasma corticosterone levels. These findings suggest that prostaglandins are involved, perhaps in an allosteric fashion, in the mechanism of action of ACTH. 相似文献
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The goal of this study is to define the effects of TCF4 hemizygosity in the context of a larger segmental deletion of chromosome 18q. Our cohort included 37 individuals with deletions
of 18q. Twenty-seven had deletions including TCF4 (TCF4
+/−); nine had deletions that did not include TCF4 (TCF4
+/+); and one individual had a microdeletion that included only the TCF4 gene. We compared phenotypic data from the participants’ medical records, survey responses, and in-person evaluations. Features
unique to the TCF4
+/− individuals included abnormal corpus callosum, short neck, small penis, accessory and wide-spaced nipples, broad or clubbed
fingers, and sacral dimple. The developmental data revealed that TCF4
+/+ individuals were only moderately developmentally delayed while TCF4
+/− individuals failed to reach developmental milestones beyond those typically acquired by 12 months of age. TCF4 hemizygosity also conferred an increased risk of early death principally due to aspiration-related complications. Hemizygosity
for TCF4 confers a significant impact primarily with regard to cognitive and motor development, resulting in a very different prognosis
for individuals hemizygous for TCF4 when compared to individuals hemizygous for other regions of distal 18q. 相似文献
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Subunits of succinyl-coenzyme A synthetase: coordination of production in Escherichia coli and discovery of a factor that precludes refolding. 总被引:1,自引:0,他引:1 下载免费PDF全文
Succinyl-coenzyme A synthetase of Escherichia coli has an alpha 2 beta 2 subunit structure. By measuring reconstituted enzyme activity present after addition of purified alpha or beta subunits to cell extracts followed by refolding, we have shown that extracts contain no significant excess of either subunit species. This equivalence suggests that the expression of the respective structural genes for the subunits is coordinately controlled. The presence of cell extract does not affect the rate or extent of reassembly of the subunits, pointing to a high degree of specificity of mutual recognition by the refolding subunits. In the course of these experiments, we have detected the presence in cell extracts of a low-molecular-weight factor that specifically inactivates unfolded alpha or beta subunits or prevents their reassembly into catalytically active enzyme. Under conditions where the subunits are completely inactivated, the factor has no detectable effect on native or refolded tetrameric enzyme, suggesting that the factor may react only with unfolded protein. 相似文献
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