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排序方式: 共有492条查询结果,搜索用时 250 毫秒
91.
Nakul Mandal Steffen Heegaard Jan Ulrik Prause Bent Honoré Henrik Vorum 《Biological procedures online》2010,12(1):56-88
The intention of this review is to provide an overview of current methodologies employed in the rapidly developing field of
ocular proteomics with emphasis on sample preparation, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass
spectrometry (MS). Appropriate sample preparation for the diverse range of cells and tissues of the eye is essential to ensure
reliable results. Current methods of protein staining for 2D-PAGE, protein labelling for two-dimensional difference gel electrophoresis,
gel-based expression analysis and protein identification by MS are summarised. The uses of gel-free MS-based strategies (MuDPIT,
iTRAQ, ICAT and SILAC) are also discussed. Proteomic technologies promise to shed new light onto ocular disease processes
that could lead to the discovery of strong novel biomarkers and therapeutic targets useful in many ophthalmic conditions. 相似文献
92.
93.
A new iridoid glucoside, hygrophiloside, has been isolated from Hygrophila difformis. Hygrophiloside is apparently identical to the so-called ‘Cardanthera-Pseudoindican’. Its structure has been established by spectroscopic means and by reduction to isoaucubin. 相似文献
94.
Rhizobium meliloti suhR suppresses the phenotype of an Escherichia coli RNA polymerase sigma 32 mutant.
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sigma 32, the product of the Escherichia coli rpoH locus, is an alternative RNA polymerase sigma factor utilized to express heat shock genes upon a sudden rise in temperature. E. coli K165 [rpoH165(Am) supC(Ts)] is temperature sensitive for growth and does not induce heat shock protein synthesis. We have isolated a locus from Rhizobium meliloti called suhR that allows E. coli K165 to grow at high temperature and induce heat shock protein synthesis. R. meliloti suhR mutants were viable and symbiotically effective. suhR was found to have no DNA or derived amino acid sequence similarity to the genes of previously sequenced sigma factors or other data base entries, although a helix-turn-helix DNA-binding protein motif is present. suhR did not restore the phenotypic defects of delta rpoH E. coli; suppression of the E. coli K165 phenotype is thus likely to involve E. coli sigma 32. Western immunoblots showed that suhR caused an approximately twofold elevation of sigma 32 levels in K165; RNA blots indicated that rpoH mRNA level and stability were not altered. Stabilization of sigma 32 protein and increased rpoH mRNA translation are thus the most probable mechanisms of suppression. 相似文献
95.
96.
Stig Pramming Birger Thorsteinsson Bent Stigsby Christian Binder 《BMJ (Clinical research ed.)》1988,296(6623):665-667
The relation between blood glucose concentration, the symptoms and signs of hypoglycaemia, and electroencephalographic changes in diabetic patients is not known. The effect of hypoglycaemia on brain function was studied in 13 patients with insulin dependent diabetes. During a gradual fall in blood glucose concentration induced by a bolus injection of insulin followed by an intravenous infusion of insulin, during 60 minutes of biochemical hypoglycaemia, and after restoration of normoglycaemia with intravenous glucose electroencephalograms were evaluated continuously by period-amplitude analysis; blood samples were taken every 10 minutes throughout. No changes were seen in electroencephalograms when the blood glucose concentration was above 3 mmol/l. At a median blood glucose concentration of 2·0 (95% confidence interval 1·7 to 2·3) mmol/l alpha activity decreased abruptly in the electroencephalograms concomitant with an increase in theta activity, reflecting neuronal dysfunction in the cortex. When the blood glucose concentration was further lowered changes were observed in the electroencephalograms indicating that deeper brain structures were affected. A normal electroencephalogram was re-established at a blood glucose concentration of 2·0 (1·8 to 2·1) mmol/l. There was no significant correlation between the blood glucose concentration at the onset of changes in the electroencephalograms and age, duration of diabetes, insulin dose, haemoglobin A1c concentration, initial blood glucose concentration, rate of fall in blood glucose concentration, and appearance of symptoms and signs of hypoglycaemia.Changes in electroencephalograms during hypoglycaemia appear and disappear at such a narrow range of blood glucose concentrations that the term threshold blood glucose concentration for the onset of such changes seems justified. 相似文献
97.
Bent Friis Theisen Bent Christensen Peter Arctander 《Journal of evolutionary biology》1995,8(1):71-80
Variation in PGM (phosphoglucomutase) and MDH (malate dehydrogenase) allozymes and in mitochondrial and nuclear (ribosomal) DNA gives evidence of at least three independent origins of triploid Trichoniscus pusillus pusillus. Much of the genetic variation found may reflect variation within the parental diploid population(s), but it is argued that some of the variation in PGM allozymes have accumulated within the parthenogenetic lines. Based upon the variation at this locus, 15 genetically distinct clones are distinguished. 相似文献
98.
E. van de Vosse Brunella Franco P. van der Bent Eugenio Montini Ulrike Orth Andre Hanauer N. Tijmes G.-J. B. van Ommen Andrea Ballabio J. T. den Dunnen Arthur A. B. Bergen 《Human genetics》1997,101(2):235-237
X-linked juvenile retinoschisis (RS) is a progressive vitreoretinal degeneration localised in Xp22.1-p22.2. A human homologue
of the retinal degeneration gene C (rdgC), a gene that in Drosophila melanogaster prevents light-induced retinal degeneration, was localised in the RS obligate gene region. We have tested the gene, designated
PPEF in humans, as a candidate gene in RS patients using RT-PCR and the protein truncation test on RNA and SSCP on DNA. No mutations
were identified, making it highly unlikely that PPEF is the gene implicated in RS. The data presented facilitate mutation analysis of the PPEF gene in other diseases which have been or will be localised to this region.
Received: 20 May 1997 / Accepted: 30 July 1997 相似文献
99.
Two iridoid glycosides have been isolated from Viburnum betulifolium. Viburnalloside, the major leaf glycoside, is composed of an iridoid aglucone acylated at C-1 with isovaleric acid and with a di-O-acetyl-β-D-allopyranosyl moiety attached through a glycosidic bond to C-11. Decapetaloside (10-hydroxyiridodial glucoside) has been isolated from the bark. The structure and absolute configuration of viburnalloside have been established by spectroscopic means, and those of decapetaloside by chemical correlation with adoxoside. 相似文献
100.