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61.
Tatiana Alves Rigamonte Fernandes Wendel Batista da Silveira Flávia Maria Lopes Passos Tiago Domingues Zucchi 《Annals of microbiology》2014,64(3):1363-1369
Laccases have become desirable enzymes for application in many industrial processes. Nowadays, most of these enzymes are obtained from fungi. Among prospective studies for bacterial laccase genes, some have included actinomycetes, but only a few studies have characterized the enzyme produced. Thus, we have isolated a laccase-producing actinomycete from forest soil under restoration process and further aimed to characterize its produced enzyme. The isolate SB086 was assigned to the Streptomyces genus by a combination of phenotypical, chemical and phylogenetic properties. Our data indicate that the bacterium produces a thermotolerant laccase. The maximum activity was obtained in the pH range 4.0–5.0 and at 50 °C in reaction mixture containing 5 mM CuSO4; thermal stability was noted at 60 °C and 70 °C—a well-desired characteristic for industry. The active enzyme presented a high molecular mass (over 100 kDa) and was less sensitive to inhibition by metal ions than generally described for bacterial laccases. Our findings support in silico data of bacterial laccase secretion, and reinforce the view that actinomycetes may be a rich source of laccase for industrial application. 相似文献
62.
Wendel Coura-Vital Valdelaine Etelvina Miranda de Araújo Ilka Afonso Reis Frederico Figueiredo Amancio Alexandre Barbosa Reis Mariangela Carneiro 《PLoS neglected tropical diseases》2014,8(12)
Background
In Brazil, case-fatality rates attributable to visceral leishmaniasis (VL) are high and knowledge of the risk factors associated with death may help reduce mortality. The aim of this study was to construct and validate a scoring system for prognosis of death from VL by using all cases reported in Brazil from 2007 to 2011.Methodology
In this historical cohort study, 18,501 VL cases were analyzed; of these, 17,345 cases were cured and 1,156 cases caused death. The database was divided into two series: primary (two-thirds of cases), to develop the model score, and secondary (one-third of cases), to validate the scoring system. Multivariate logistic regression models were performed to identify factors associated with death from VL, and these were included in the scoring system.Principal Findings
The factors associated with death from VL were: bleeding (score 3); splenomegaly (score 1); edema (score 1); weakness (score 1); jaundice (score 1); Leishmania–HIV co-infection (score 1); bacterial infection (score 1); and age (≤0.5 years [score 5]; >0.5 and ≤1 [score 2]; >19 and ≤50 [score 2]; >50 and <65 [score 3]; ≥65 [score 5]). It was observed that patients with a score of 4 had a probability of death of approximately 4.5% and had a worse prognosis. The sensitivity, specificity, and accuracy of this score were 89.4, 51.2, and 53.5, respectively.Conclusions/Significance
The scoring system based on risk factors for death showed good performance in identifying patients with signs of severity at the time of clinical suspicion of VL and can contribute to improving the surveillance system for reducing case fatalities. The classification of patients according to their prognosis for death may assist decision-making regarding the transfer of the patients to hospitals more capable of handling their condition, admission to the intensive care unit, and adequate support and specific treatment. 相似文献63.
Rudolf Ladenstein Otto Epp Klaus Bartels Alwyn Jones Robert Huber Albrecht Wendel 《Journal of molecular biology》1979,134(2):199-218
The three-dimensional structure of bovine erythrocyte glutathione peroxidase, a tetrameric enzyme containing 4 gram atoms of selenium per mole (Mr = 84,000), has been determined at 2.8 Å resolution using the multiple isomorphous replacement method. By correlation calculations in Patterson space the tetramers were shown to exhibit molecular [222] symmetry, proving the monomers to be identical or at least very similar.The monomer consists of a single polypeptide chain of 178 amino acid residues. Its shape is nearly spherical with a radius of . A tentative sequence corresponding to a partially refined model (R = 0.38) is given. Each subunit is built up from a central core of two parallel and two anti-parallel strands of pleated sheet surrounded by four α-helices. One of the helices runs antiparallel to the neighbouring β-strands giving rise to a βαβ substructure, an architecture that has been found in several other proteins e.g. flavodoxin, thioredoxin, rhodanese and dehydrogenases. A comparison of the glutathione peroxidase subunit structure with thioredoxin-S2 revealed large regions of structural resemblance. The central four-stranded β structure together with two parallel α-helices resembles nearly 80% of the thioredoxin fold.The active sites of glutathione peroxidase are located in flat depressions on the molecular surface. Probably each active centre is built up by segments from two subunits. The catalytically active selenocysteines were found at the N-terminal ends of long α-helices and are surrounded by an accumulation of aromatic side-chains. A difference Fourier map between oxidized and substrate-reduced glutathione peroxidase as well as heavy-atom binding led to the conclusion that the two-electron redox-cycle involves a reversible transition of the active-site selenium from a selenenic acid (RSeOH) to a seleninic acid (RSeOOH). 相似文献
64.
Martina Wendel Anna Petzold Roland Koslowski Michael Kasper Antje Augstein Lilla Knels Jörg-Uwe Bleyl Thea Koch 《Histochemistry and cell biology》2000,122(5):507-517
Pulmonary fibrosis is characterized by excessive extracellular matrix deposition with concomitant loss of gas exchange units, and endothelin-1 (ET-1) has been implicated in its pathogenesis. Increased levels of ET-1 from tissues and bronchoalveolar lavage have been reported in patients with pulmonary fibrosis and in animal models after intratracheal bleomycin. We characterized the cellular distribution of alveolar ET receptors by immunohistochemistry in bleomycin-induced pulmonary fibrosis in the rat and determined the regulation by bleomycin of ET receptor mRNA expression in isolated alveolar macrophages and rat lung fibroblasts. We found significant increases in the numbers of fibroblasts and macrophages at day 7 compared to day 28 and control animals. ETB receptor immunoreactivity was observed on fibroblasts and invading monocytes. Isolated fibroblasts expressed both ETA and ETB receptor mRNA, and ETA receptor mRNA was upregulated by bleomycin. Isolated resident alveolar macrophages expressed neither ETA nor ETB receptor mRNA which were also not induced by bleomycin. We conclude that, while ETB receptor stimulation of fibroblasts and monocytes recruited during bleomycin-induced lung injury exerts antagonistic effects on fibroblast collagen synthesis, the observed increase in the number of fibroblasts in vivo and upregulation of fibroblast ETA receptor mRNA by bleomycin in vitro point to a predominance of the profibrotic effects of ET receptor engagement. 相似文献
65.
Divergent Evolution of Plant NBS-LRR Resistance Gene Homologues in Dicot and Cereal Genomes 总被引:36,自引:0,他引:36
The majority of plant disease resistance genes are members of very large multigene families. They encode structurally related
proteins containing nucleotide binding site domains (NBS) and C-terminal leucine rich repeats (LRR). The N-terminal region
of some resistance genes contain a short sequence called TIR with homology to the animal innate immunity factors, Toll and interleukin receptor-like genes. Only a few plant resistance genes have been functionally analyzed and the origin and
evolution of plant resistance genes remain obscure. We have reconstructed gene phylogeny by exhaustive analysis of available
genome and amplified NBS domain sequences. Our study shows that NBS domains faithfully predict whole gene structure and can
be divided into two major groups. Group I NBS domains contain group-specific motifs that are always linked with the TIR sequence
in the N terminus. Significantly, Group I NBS domains and their associated TIR domains are widely distributed in dicot species
but were not detected in cereal databases. Furthermore, Group I specific NBS sequences were readily amplified from dicot genomic
DNA but could not be amplified from cereal genomic DNA. In contrast, Group II NBS domains are always associated with putative
coiled-coil domains in their N terminus and appear to be present throughout the angiosperms. These results suggest that the
two main groups of resistance genes underwent divergent evolution in cereal and dicot genomes and imply that their cognate
signaling pathways have diverged as well.
Received: 17 May 1999 / Accepted: 25 September 1999 相似文献
66.
67.
Erythronium propullans is a narrow endemic restricted to two counties in southeastern Minnesota. It coexists at all sites with the widespread common white trout lily, E. albidum. Erythronium albidum has both sexual and asexual reproduction; it has been suggested that E. propullans reproduces strictly by vegetative means. Electrophoretic analysis of 15 enzyme systems encoded by a minimum of 37 genetic loci revealed considerable genetic variation within and among E. propullans populations. However, all measures of variability calculated from allozyme data demonstrate that E. propullans maintains lower levels of genetic variation than E. albidum. There is also evidence for limited gene flow among E. propullans populations, whereas all E. albidum populations are genetically similar. Clonal diversity is also lower in E. propullans. Only 21 clones were found in 100 individuals sampled whereas virtually every one of the 70 individuals of E. albidum sampled had a unique multilocus genotype. The clones of E. propullans cluster into 3 genetically dissimilar groups; variation within each cluster indicates that some sexual recombination does occur. We discuss the effects of clonality and endemism on genetic variation, reasons why the clonal habit might preserve genetic variation, and suggest that the lower variability in E. propullans is due primarily to the genetic bottleneck it experienced at the time of its origin. Isozyme data suggest that E. propullans is a derivative of E. albidum. Based on the degree of genetic similarity and information on the glacial history of the region, we suggest that E. propullans is a local derivative of E. albidum, having arisen no more than 9,000 years ago. 相似文献
68.
H. Wendel 《European biophysics journal : EBJ》1985,11(4):239-242
Recently, we have developed an analytical, semi-microscopic theory for the macroscopic behavior of a solvent-containing black lipid film subjected to an electric cross film voltage, . Here we employ the theoretical expressions derived for the disjoining pressure, D, the film elasticity, F, and the film tension, F, to construct the stability diagram of the film, in the D-. Depending on its state (D, ), the film is stable or is prone to squeezing or bending deformations. For a monooleate film we show how the destruction of the plane film due to a periodic thickness fluctuation (squeezing) is facilitated by two mechanisms: i) lowering of D at fixed ; ii) lowering of at fixed D, provided that the film is in a stable state characterized by D<–7.03×103 dyne/cm2 and >0 mV. Bending of a low tension film (single interface tension s 0.025 dyne/cm1) can be achieved only for >170 mV and D > –8.7 × 104 dyne/cm2. Finally, we demonstrate the existence of a marginal state (
D
0
, 0) where the film is predicted to exhibit strong fluctuations both in the squeezing and in the bending mode. 相似文献
69.
Jonathan F. Wendel Major M. Goodman C. W. Stuber J. B. Beckett 《Biochemical genetics》1988,26(5-6):421-445
Electrophoretic variation and inheritance of four novel enzyme systems were studied in maize (Zea mays L.). A minimum of 10 genetic loci collectively encodes isozymes of aconitate hydratase (ACO; EC 4.2.1.3.), adenylate kinase
(ADK; EC 2.7.4.3), NADH dehydrogenase (DIA; EC 1.6.99.—), and shikimate dehydrogenase (SAD; EC 1.1.1.25). At least four loci
are responsible for the genetic control of ACO. Genetic data for two of the encoding loci,Aco1 andAco4, demonstrated that at least two maize ACOs are active as monomers. Analysis of organellar preparations suggests that ACO1
and ACO4 are localized in the cytosolic and mitochondrial subcellular fractions, respectively. Maize ADK is encoded by a single
nuclear locus,Adk1, governing monomeric enzymes that are located in the chloroplasts. Two cytosolic and two mitochondrial forms of DIA were
electrophoretically resolved. Segregation analyses demonstrated that the two cytosolic isozymes are controlled by separate
loci,Dia1 andDia2, coding for products that are functional as monomers (DIA1) and dimers (DIA2). The major isozyme of SAD is apparently cytosolic,
although an additional faintly staining plastid form may be present. Alleles atSad1 are each associated with two bands that cosegregate in controlled crosses. Linkage analyses and crosses with B-A translocation
stocks were effective in determining the map locations of six loci, including the previously described but unmapped locusAcp4. Several of these loci were localized to sparsely mapped regions of the genome.Dia2 andAcp4 were placed on the distal portion of the long arm of chromosome 1, 12.6 map units apart.Dia1 was localized to chromosome 2, 22.2 centimorgans (cM) fromB1. Aco1 was mapped to chromosome 4, 6.2 cM fromsu1. Adk1 was placed on the poorly marked short arm of chromosome 6, 8.1 map units fromrgd1. Less than 1% recombination was observed betweenGlu1 (on chromosome 10) andSad1. In contrast to many other maize isozyme systems, there was little evidence of gene duplication or of parallel linkage relationships
for these allozyme loci.
This work was supported by grants from Pioneer Hi-Bred International, Inc., of Johnston, Iowa, the National Institute of Health
(Research Grant GM11546), and the United States Department of Agriculture (Competitive Research Grant 83-CRCR-1-1273). This
is Paper No. 11372 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh. 相似文献
70.
Cartilage matrix proteins. An acidic oligomeric protein (COMP) detected only in cartilage. 总被引:28,自引:0,他引:28
E Hedbom P Antonsson A Hjerpe D Aeschlimann M Paulsson E Rosa-Pimentel Y Sommarin M Wendel A Oldberg D Heineg?rd 《The Journal of biological chemistry》1992,267(9):6132-6136
An Mr = 524,000 oligomeric protein was isolated from bovine cartilage and designated COMP (Cartilage Oligomeric Matrix Protein). The protein is composed of disulfide-bonded subunits with an apparent Mr of 100,000 each. It is markedly anionic, probably due to its high contents of aspartic acid and glutamic acid, as well as to its substitution with negatively charged carbohydrates. COMP was found in all cartilages analyzed, but could not be detected in other tissues by enzyme-linked immunosorbent assay of guanidine HCl extracts. Within a given cartilage, COMP shows a preferential localization to the territorial matrix surrounding the chondrocytes. 相似文献