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81.
Modification of fatty acid composition in tomato (Lycopersicon esculentum) by expression of a borage delta6-desaturase 总被引:2,自引:0,他引:2
The improvement of nutritional quality is one potential application for the genetic modification of plants. One possible target
for such manipulation is the modification of fatty acid metabolism. In this work, expression of a borage Δ6-desaturase cDNA in tomato (Lycopersicon esculentum L.) has been shown to produce γ-linolenic acid (GLA; 18:3 Δ6,9,12) and octadecatetraenoic acid (OTA; 18:4 Δ6,9,12,15) in transgenic leaf and fruit tissue. This genetic modification has also, unexpectedly, resulted in a reduction in the percentage
of linoleic acid (LA 18:2 Δ9,12) and a concomitant increase in the percentage of α-linolenic acid (ALA; 18:3 Δ9,12,15) in fruit tissue. These changes in fatty acid composition are thought to be beneficial for human health. 相似文献
82.
Yu LG Andrews N Weldon M Gerasimenko OV Campbell BJ Singh R Grierson I Petersen OH Rhodes JM 《The Journal of biological chemistry》2002,277(27):24538-24545
Nuclear localization sequence-dependent nuclear protein import is essential for maintaining cell function and can be selectively blocked in epithelial cells by mushroom (Agaricus bisporus) lectin. Here we report that a major intracellular ligand for this lectin is an N-terminally truncated form of oxygen-regulated protein 150 (Orp150), which lacks the endoplasmic reticulum translocation signal peptide of full-length Orp150. This cytoplasmic form of Orp150 expresses the lectin carbohydrate ligand (sialyl-2,3-galactosyl-beta1,3-N-acetylgalactosamine-alpha) and is shown to be essential for nuclear localization sequence-dependent nuclear protein import. 相似文献
83.
Repeated evolution of an acetate-crossfeeding polymorphism in long-term populations of Escherichia coli 总被引:1,自引:0,他引:1
Six out of 12 independent replicate populations of Escherichia coli
maintained in long-term glucose-limited continuous culture for up to
approximately 1,750 generations evolve polymorphisms maintained by acetate
crossfeeding. In all cases, the acetate-crossfeeding phenotype is
associated with semiconstitutive overexpression of acetyl CoA synthetase,
which allows for the enhanced uptake of low levels of exogenous acetate.
Mutations in the 5' regulatory region of the acetyl CoA synthetase locus
are responsible for all the acetate crossfeeding phenotypes found. These
changes were either transposable-element insertions or a single T-->A
nucleotide substitution at position -93 relative to the acs gene
translation start site.
相似文献
84.
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86.
The properties and function of rapidly-labelled nuclear RNA 总被引:1,自引:1,他引:0
Summary Nuclei were isolated from cultured cells of Acer pseudoplatanus L. previously pulse-labelled with [5-3H]uridine or [32P]phosphate and the properties of the rapidly-labelled RNA were studied. Polyacrylamide gel electrophoresis showed ribosomal RNA precursors and processing intermediates with molecular weights of 3.4, 2.5, 1.4 and 1×106 daltons, together with polydisperse RNA. The relative proportions of ribosomal RNA precursors and polydisperse RNA varied according to the length of the labelling period, but after 30 min approximately 90% of the radioactive RNA was polydisperse. The relationship between this polydisperse RNA and messenger RNA was investigated. The percentage of total nuclear RNA retained by chromatography on oligodeoxythymidylic acid-cellulose columns varied from 6% to 16% depending on the length of the labelling period. This RNA fraction, which has an adenylic acid content of approximately 45%, is assumed to represent RNA with polyadenylic acid sequences attached. A larger proportion of the nuclear polydisperse RNA lacked polyadenylic acid. Both types of polydisperse RNA were similar in size and during polyacrylamide gel electrophoresis migrated as broad peaks with an average molecular weight of approximately 106 daltons. The polydisperse nuclear RNA that lacks polyadenylic acid was found to be similar in nucleotide composition to ribosomal RNA and is assumed to represent growing chains of ribosomal precursor RNA. After short labelling times the majority of the radioactivity incorporated into nuclear RNA is present in molecules of this type. This suggests that the designation of pulse-labelled polydisperse RNA as messenger RNA or precursor to messenger RNA solely on the basis of rapid labelling and size heterogeneity is unsound. The average molecular weight of the polyadenylic acid-containing messenger RNA from the cytoplasm was less than that of the corresponding nuclear RNA (6 and 9×105 daltons respectively). This suggest either that the majority of the nuclear polyadenylic acid-containing RNA does not enter the cytoplasm, or if it does, that it first undergoes a reduction in size.Abbreviations rRNA
ribosomal RNA
- mRNA
messenger
- RNA
poly(A), polyadenylic acid, poly(A) and poly(A)
- RNA
RNA with and without poly(A) sequences attached
- poly(U)
polyuridylic acid
- oligo (dT)-cellulose
cellulose with oligo deoxythymidylic acid covalently attached
- C
cytidylic acid
- A
adenylic acid
- G
guanylic acid
- U
uridylic acid 相似文献
87.
Degradation of isolated tomato cell walls by purified polygalacturonase in vitro 总被引:14,自引:7,他引:7 下载免费PDF全文
Cell wall preparations from green pericarp of normal and mutant Neverripe (Nr) and ripening inhibitor (rin) tomato (Lycopersicon esculentum Mill.) fruit were all equally degraded in vitro by a cell wall-bound protein extract from ripe normal tomatoes. 相似文献
88.
Cañada-Cañada F Bautista-Sánchez A Taverna M Prognon P Maillard P Grierson DS Kasselouri A 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2005,821(2):166-172
This paper reports, for the first time, a reversed-phase high performance liquid chromatographic method for the simultaneous determination of seven glucoconjugated and non-glucoconjugated porphyrins and chlorins, using near infra-red fluorescence detection. Chromatographic separation was performed on nucleosil-CN analytical column using an isocratic acetonitrile-0.1% (w/v) TFA at pH 1.8 (55:45, v/v) as mobile phase. Wavelength gradient was employed for sensitive detection, porphyrins derivates were monitored at lambda(exc) = 440 nm and lambda(emi) = 680 nm; and chlorins derivates at lambda(exc) = 420 nm, lambda(emi) = 650 nm. The method was validated and applied to monitor the biodegradation of a tri glucoconjugated chlorin derivative, TPC(glu)3, in spiked samples of human serum. 相似文献
89.
90.
Mitochondria display a variety of shapes, ranging from small and spherical or the classical tubular shape to extended networks. Shape transitions occur frequently and include fusion, fission, and branching. It was reported that some mitochondrial shape transitions are developmentally regulated, whereas others were linked to disease or apoptosis. However, if and how mitochondrial function controls mitochondrial shape through regulation of mitochondrial fission and fusion is unclear. Here, we show that inhibitors of electron transport, ATP synthase, or the permeability transition pore (mtPTP) induced reversible mitochondrial fission. Mitochondrial fission depended on dynamin-related protein 1 (DRP1) and F-actin: Disruption of F-actin attenuated fission and recruitment of DRP1 to mitochondria. In contrast, uncoupling of electron transport and oxidative phosphorylation caused mitochondria to adopt a distinct disk shape. This shape change was independent of the cytoskeleton and DRP1 and was most likely caused by swelling. Thus, disruption of mitochondrial function rapidly and reversibly altered mitochondrial shape either by activation of DRP1-dependent fission or by swelling, indicating a close relationship between mitochondrial fission, shape, and function. Furthermore, our results suggest that the actin cytoskeleton is involved in mitochondrial fission by facilitating mitochondrial recruitment of DRP1. 相似文献