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511.
Habitat patches, depending on the degree of differentiation from the matrix, can add few or many elements to the species pool of a particular landscape. Their importance to biodiversity is particularly relevant in areas with complex landscapes, where natural, naturalized, or managed habitats are interspersed by small patches of habitat types with very different biophysical characteristics; e.g., fruit orchards and riparian areas. This is the case of the montado landscape, a cork oak agroforestry system that largely covers south-western Portugal. We evaluated whether the high mammalian biodiversity found in this system is, in part, the cumulative result of the species found in the non-matrix habitats. Our results indicate that in areas where there are inclusions of orchards/olive yards and riparian vegetation in the cork oak woodland, a significantly higher number of mammalian species are present. We further detected a positive effect of low human disturbance on mammal diversity. Ultimately, our results can be used by managers to augment their management options, since we show that the inclusion and maintenance of non-matrix habitat patches in cork oak agro-silvo-forestry systems can help to maximize mammal biodiversity without compromising services associated with agriculture and forestry. 相似文献
512.
Pedro Simões Marta Pascual Josiane Santos Michael R Rose Margarida Matos 《BMC evolutionary biology》2009,9(1):133-3
Here we present a correction to our article "Evolutionary dynamics of molecular markers during local adaptation: a case study
in Drosophila subobscura ". We have recently detected an error concerning the application of the Ln RH formula – a test to detect positive selection
– to our microsatellite data. Here we provide the corrected data and discuss its implications for our overall findings. The
corrections presented here have produced some changes relative to our previous results, namely in a locus (dsub14) that presents indications of being affected by positive selection. In general, our populations present less consistent indications
of positive selection for this particular locus in both periods studied – between generations 3 and 14 and between generation
14 and 40 of laboratory adaptation. Despite this, the main findings of our study regarding the possibility of positive selection
acting on that particular microsatellite still hold. As previously concluded in our article, further studies should be performed
on this specific microsatellite locus (and neighboring areas) to elucidate in greater detail the evolutionary forces acting
on this specific region of the O chromosome of Drosophila subobscura. 相似文献
513.
Margarida Coelho Fernando Sequeira Donata Luiselli Sandra Beleza Jorge Rocha 《BMC evolutionary biology》2009,9(1):80
Background
Current information about the expansion of Bantu-speaking peoples is hampered by the scarcity of genetic data from well identified populations from southern Africa. Here, we fill an important gap in the analysis of the western edge of the Bantu migrations by studying for the first time the patterns of Y-chromosome, mtDNA and lactase persistence genetic variation in four representative groups living around the Namib Desert in southwestern Angola (Ovimbundu, Ganguela, Nyaneka-Nkumbi and Kuvale). We assessed the differentiation between these populations and their levels of admixture with Khoe-San groups, and examined their relationship with other sub-Saharan populations. We further combined our dataset with previously published data on Y-chromosome and mtDNA variation to explore a general isolation with migration model and infer the demographic parameters underlying current genetic diversity in Bantu populations. 相似文献514.
M Margarida Souto-Carneiro Vijayabhanu Mahadevan Kazuki Takada Ruth Fritsch-Stork Toshihiro Nanki Margaret Brown Thomas A Fleisher Mildred Wilson Raphaela Goldbach-Mansky Peter E Lipsky 《Arthritis research & therapy》2009,11(3):R84-12
Introduction
Disturbances in peripheral blood memory B cell subpopulations have been observed in various autoimmune diseases, but have not been fully delineated in rheumatoid arthritis (RA). Additionally, the possible role of tumour necrosis factor (TNF) in regulating changes in specific peripheral blood memory B cell subsets in RA is still unclear. 相似文献515.
Carlos A. Fernandes Mónica Rodrigues Ghaiet M. Hajji Paul Vercammen Michael W. Bruford Margarida Santos-Reis 《Conservation Genetics》2009,10(6):1931-1934
We report the isolation and characterization of 11 polymorphic tetranucleotide microsatellite loci in the common genet (Genetta genetta) from genomic libraries enriched for (AAAG)
n
and (AGAT)
n
repeat sequences. We chose to develop tetranucleotide repeats because they can be scored less ambiguously. In a sample of
25 individuals, we observed between four and thirteen alleles per locus and their observed and expected heterozygosities ranged
from 0.60 to 0.84 and from 0.68 to 0.92, respectively. All genotypic frequencies conformed to Hardy–Weinberg equilibrium expectations
and there were no instances of linkage disequilibrium detected between pairs of loci. These loci will be of use in studies
of population genetics, historical demography, and molecular ecology of the common genet. 相似文献
516.
A nuclear gene encoding a 9.8 kDa subunit of complex I, the homologue of mammalian MWFE protein, was identified in the genome of Neurospora crassa. The gene was cloned and inactivated in vivo by the generation of repeat-induced point mutations. Fungal mutant strains lacking the 9.8 kDa polypeptide were subsequently isolated. Analyses of mitochondrial proteins from mutant nuo9.8 indicate that the membrane and peripheral arms of complex I fail to assemble. Respiration of mutant mitochondria on matrix NADH is rotenone-insensitive, confirming that the 9.8 kDa protein is required for the assembly and activity of complex I. We found a similarity between the MWFE homologues and the C-terminal part of the nqrA subunit of bacterial Na(+)-translocating NADH:quinone oxidoreductases (Na(+)-NQR), suggesting a link between proton-pumping and sodium-pumping NADH dehydrogenases. 相似文献
517.
Confocal FRET microscopy to measure clustering of ligand-receptor complexes in endocytic membranes
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The dynamics of protein distribution in endocytic membranes are relevant for many cellular processes, such as protein sorting, organelle and membrane microdomain biogenesis, protein-protein interactions, receptor function, and signal transduction. We have developed an assay based on Fluorescence Resonance Energy Microscopy (FRET) and novel mathematical models to differentiate between clustered and random distributions of fluorophore-bound molecules on the basis of the dependence of FRET intensity on donor and acceptor concentrations. The models are tailored to extended clusters, which may be tightly packed, and account for geometric exclusion effects between membrane-bound proteins. Two main criteria are used to show that labeled polymeric IgA-ligand-receptor complexes are organized in clusters within apical endocytic membranes of polarized MDCK cells: 1), energy transfer efficiency (E%) levels are independent of acceptor levels; and 2), with increasing unquenched donor: acceptor ratio, E% decreases. A quantitative analysis of cluster density indicates that a donor-labeled ligand-receptor complex should have 2.5-3 labeled complexes in its immediate neighborhood and that clustering may occur at a limited number of discrete membrane locations and/or require a specific protein that can be saturated. Here, we present a new sensitive FRET-based method to quantify the co-localization and distribution of ligand-receptor complexes in apical endocytic membranes of polarized cells. 相似文献
518.
Identification of in vivo enzyme activities in the cometabolism of glucose and acetate by Saccharomyces cerevisiae by using 13C-labeled substrates
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A detailed characterization of the central metabolic network of Saccharomyces cerevisiae CEN.PK 113-7D was carried out during cometabolism of different mixtures of glucose and acetate, using aerobic C-limited chemostats in which one of these two substrates was labeled with 13C. To confirm the role of malic enzyme, an isogenic strain with the corresponding gene deleted was grown under the same conditions. The labeling patterns of proteinogenic amino acids were analyzed and used to estimate metabolic fluxes and/or make inferences about the in vivo activities of enzymes of the central carbon metabolism and amino acid biosynthesis. Malic enzyme flux increased linearly with increasing acetate fraction. During growth on a very-high-acetate fraction, the activity of malic enzyme satisfied the biosynthetic needs of pyruvate in the mitochondria, while in the cytosol pyruvate was supplied via pyruvate kinase. In several cases enzyme activities were unexpectedly detected, e.g., the glyoxylate shunt for a very-low-acetate fraction, phosphoenolpyruvate carboxykinase for an acetate fraction of 0.46 C-mol of acetate/C-mol of substrate, and glucose catabolism to CO2 via the tricarboxylic acid cycle for a very-high-acetate fraction. Cytoplasmic alanine aminotransferase activity was detected, and evidence was found that α-isopropylmalate synthase has two active forms in vivo, one mitochondrial and the other a short cytoplasmic form. 相似文献
519.
The development of microarray technology offers the unprecedented possibility of studying the expression of thousands of genes in one experiment. Its exploitation in the glycobiology field will eventually allow the parallel investigation of the expression of many glycosyltransferases, which will ultimately lead to an understanding of the regulation of glycoconjugate synthesis. While numerous gene arrays are available on the market, e.g. the Affymetrix GeneChip arrays, glycosyltransferases are not adequately represented, which makes comprehensive surveys of their gene expression difficult. This chapter describes the main issues related to the establishment of a custom glycogenes array. 相似文献
520.
Pedro A.G. Santos A. Cristina Figueiredo Pedro M.L. Lourenço José G. Barroso Luis G. Pedro M. Margarida Oliveira Jan Schripsema Stanley G. Deans Johannes J.C. Scheffer 《Biotechnology letters》2002,24(12):1031-1036
Transformed root cultures of Anethum graveolens were induced by inoculation of aseptically grown seedlings with Agrobacterium rhizogenes carrying plasmid pRi 1855. The main component of the essential oils from the fruits and from the roots of the parent plant was carvone, whereas -phellandrene and apiole were dominant in the oil from, respectively, the aerial parts and the hairy roots. The essential oils from the fruits, aerial parts and roots of the parent plant were at 2%, 0.3% and 0.06% (v/w), respectively, but only 0.02% (v/w) in the hairy root cultures. Growth of the hairy root cultures reached 600 mg dry wt/50 ml medium after 50 days. The essential oil composition did not change significantly during their growth. 相似文献