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151.
Benjamin Cull Joseane Lima Prado Godinho Juliany Cola Fernandes Rodrigues Benjamin Frank Uta Schurigt Roderick AM Williams Graham H Coombs Jeremy C Mottram 《Autophagy》2014,10(12):2143-2157
Autophagy is a central process behind the cellular remodeling that occurs during differentiation of Leishmania, yet the cargo of the protozoan parasite''s autophagosome is unknown. We have identified glycosomes, peroxisome-like organelles that uniquely compartmentalize glycolytic and other metabolic enzymes in Leishmania and other kinetoplastid parasitic protozoa, as autophagosome cargo. It has been proposed that the number of glycosomes and their content change during the Leishmania life cycle as a key adaptation to the different environments encountered. Quantification of RFP-SQL-labeled glycosomes showed that promastigotes of L. major possess ∼20 glycosomes per cell, whereas amastigotes contain ∼10. Glycosome numbers were significantly greater in promastigotes and amastigotes of autophagy-defective L. major Δatg5 mutants, implicating autophagy in glycosome homeostasis and providing a partial explanation for the previously observed growth and virulence defects of these mutants. Use of GFP-ATG8 to label autophagosomes showed glycosomes to be cargo in ∼15% of them; glycosome-containing autophagosomes were trafficked to the lysosome for degradation. The number of autophagosomes increased 10-fold during differentiation, yet the percentage of glycosome-containing autophagosomes remained constant. This indicates that increased turnover of glycosomes was due to an overall increase in autophagy, rather than an upregulation of autophagosomes containing this cargo. Mitophagy of the single mitochondrion was not observed in L. major during normal growth or differentiation; however, mitochondrial remnants resulting from stress-induced fragmentation colocalized with autophagosomes and lysosomes, indicating that autophagy is used to recycle these damaged organelles. These data show that autophagy in Leishmania has a central role not only in maintaining cellular homeostasis and recycling damaged organelles but crucially in the adaptation to environmental change through the turnover of glycosomes. 相似文献
152.
Immunological similarities between specific chloroplast ribosomal proteins from Chlamydomonas reinhardtii and ribosomal proteins from Escherichia coli 总被引:11,自引:0,他引:11
Polyclonal antibodies were elicited against seven of the 33 different
proteins of the large subunit of the chloroplast ribosome from
Chlamydomonas reinhardtii. Three of these proteins are synthesized in the
chloroplast and four are made in the cytoplasm and imported. In western
blots, six of the seven antisera are monospecific for their respective
large subunit ribosomal proteins, and none of these antisera cross-reacted
with any chloroplast small subunit proteins from C. reinhardtii. Antisera
to the three chloroplast-synthesized ribosomal proteins cross-reacted with
specific Escherichia coli large subunit proteins of comparable charge and
molecular weight. Only one of the four antisera to the chloroplast
ribosomal proteins synthesized in the cytoplasm cross-reacted with an E.
coli large subunit protein. None of the antisera cross-reacted with any E.
coli small subunit proteins. On the assumption of a procaryotic,
endosymbiotic origin for the chloroplast, those chloroplast ribosomal
proteins still synthesized within the organelle appear to have retained
more antigenic sites in common with E. coli ribosomal proteins than have
those which are now the products of cytoplasmic protein synthesis. Antisera
to this cytoplasmically synthesized group of chloroplast ribosomal proteins
did not recognize any antigenic sites among C. reinhardtii cytoplasmic
ribosomal proteins, suggesting that the genes for the cytoplasmically
synthesized chloroplast ribosomal proteins either are not derived from the
cytoplasmic ribosomal protein genes or have evolved to a point where no
antigenic similarities remain.
相似文献
153.
Plínio Delatorre Bruno AM Rocha Emmanuel P Souza Taianá M Oliveira Gustavo A Bezerra Frederico BMB Moreno Beatriz T Freitas Tatiane Santi-Gadelha Alexandre H Sampaio Walter F Azevedo Jr Benildo S Cavada 《BMC structural biology》2007,7(1):1-9
Background
Lectins are mainly described as simple carbohydrate-binding proteins. Previous studies have tried to identify other binding sites, which possible recognize plant hormones, secondary metabolites, and isolated amino acid residues. We report the crystal structure of a lectin isolated from Canavalia gladiata seeds (CGL), describing a new binding pocket, which may be related to pathogen resistance activity in ConA-like lectins; a site where a non-protein amino-acid, α-aminobutyric acid (Abu), is bound.Results
The overall structure of native CGL and complexed with α-methyl-mannoside and Abu have been refined at 2.3 Å and 2.31 Å resolution, respectively. Analysis of the electron density maps of the CGL structure shows clearly the presence of Abu, which was confirmed by mass spectrometry.Conclusion
The presence of Abu in a plant lectin structure strongly indicates the ability of lectins on carrying secondary metabolites. Comparison of the amino acids composing the site with other legume lectins revealed that this site is conserved, providing an evidence of the biological relevance of this site. This new action of lectins strengthens their role in defense mechanisms in plants. 相似文献154.
Alpina Begossi Svetlana V Salivonchyk Luciana G Araujo Tainá B Andreoli Mariana Clauzet Claudia M Martinelli Allan GL Ferreira Luiz EC Oliveira Renato AM Silvano 《Journal of ethnobiology and ethnomedicine》2011,7(1):1-23
In this study, we sought to investigate the biology (diet and reproduction) and ethnobiology (fishers knowledge and fishing spots used to catch snappers) of five species of snappers (Lutjanidae), including Lutjanus analis, Lutjanus synagris, Lutjanus vivanus, Ocyurus chrysurus, and Romboplites saliens at five sites along the northeast (Riacho Doce, Maceió in Alagoas State, and Porto do Sauípe, Entre Rios at Bahia State) and the southeast (SE) Brazilian coast (Paraty and Rio de Janeiro cities at Rio de Janeiro State, and Bertioga, at São Paulo State.). We collected 288 snappers and interviewed 86 fishermen. The stomach contents of each fish were examined and macroscopic gonad analysis was performed. Snappers are very important for the fisheries of NE Brazil, and our results indicated that some populations, such as mutton snapper (L. analis) and lane snapper (L. synagris), are being caught when they are too young, at early juvenile stages. Local knowledge has been shown to be a powerful tool for determining appropriate policies regarding management of target species, and artisanal fishermen can be included in management processes. Other suggestions for managing the fisheries are discussed, including proposals that could provide motivation for artisanal fishermen to participate in programs to conserve resources, such as co-management approaches that utilize local knowledge, the establishment of fishing seasons, and compensation of fishermen, through 'payment for environmental services'. These suggestions may enhance the participation of local artisanal fishermen in moving to a more realistic and less top-down management approach of the fish population. 相似文献
155.
E N Amuzu-Aweh P Bijma B P Kinghorn A Vereijken J Visscher J AM van Arendonk H Bovenhuis 《Heredity》2013,111(6):530-538
Prediction of heterosis has a long history with mixed success, partly due to low numbersof genetic markers and/or small data sets. We investigated the prediction of heterosisfor egg number, egg weight and survival days in domestic white Leghorns, using∼400 000 individuals from 47 crosses and allele frequencies on∼53 000 genome-wide single nucleotide polymorphisms (SNPs). When heterosis isdue to dominance, and dominance effects are independent of allele frequencies, heterosisis proportional to the squared difference in allele frequency (SDAF) between parental purelines (not necessarily homozygous). Under these assumptions, a linear model includingregression on SDAF partitions crossbred phenotypes into pure-line values and heterosis,even without pure-line phenotypes. We therefore used models where phenotypes of crossbredswere regressed on the SDAF between parental lines. Accuracy of prediction was determinedusing leave-one-out cross-validation. SDAF predicted heterosis for egg number and weightwith an accuracy of ∼0.5, but did not predict heterosis for survival days. Heterosispredictions allowed preselection of pure lines before field-testing, saving∼50% of field-testing cost with only 4% loss in heterosis. Accuraciesfrom cross-validation were lower than from the model-fit, suggesting that accuraciespreviously reported in literature are overestimated. Cross-validation also indicated thatdominance cannot fully explain heterosis. Nevertheless, the dominance model hadconsiderable accuracy, clearly greater than that of a general/specific combiningability model. This work also showed that heterosis can be modelled even when pure-linephenotypes are unavailable. We concluded that SDAF is a useful predictor of heterosis incommercial layer breeding. 相似文献
156.
157.
Corry-Anke Brandsma Machteld N Hylkema Barry WA van der Strate Dirk-Jan Slebos Marjan A Luinge Marie Geerlings Wim Timens Dirkje S Postma Huib AM Kerstjens 《Respiratory research》2008,9(1):17
Background
Smoking is the most important cause for the development of COPD. Since not all smokers develop COPD, it is obvious that other factors must be involved in disease development. We hypothesize that heme oxygenase-1 (HO-1), a protective enzyme against oxidative stress and inflammation, is insufficiently upregulated in COPD.The effects of HO-1 modulation on cigarette smoke induced inflammation and emphysema were tested in a smoking mouse model.Methods
Mice were either exposed or sham exposed to cigarette smoke exposure for 20 weeks. Cobalt protoporphyrin or tin protoporphyrin was injected during this period to induce or inhibit HO-1 activity, respectively. Afterwards, emphysema development, levels of inflammatory cells and cytokines, and the presence of B-cell infiltrates in lung tissue were analyzed.Results
Smoke exposure induced emphysema and increased the numbers of inflammatory cells and numbers of B-cell infiltrates, as well as the levels of inflammatory cytokines in lung tissue. HO-1 modulation had no effects on smoke induced emphysema development, or the increases in neutrophils and macrophages and inflammatory cytokines. Interestingly, HO-1 induction prevented the development of smoke induced B-cell infiltrates and increased the levels of CD4+CD25+ T cells and Foxp3 positive cells in the lungs. Additionally, the CD4+CD25+ T cells correlated positively with the number of Foxp3 positive cells in lung tissue, indicating that these cells were regulatory T cells.Conclusion
These results support the concept that HO-1 expression influences regulatory T cells and indicates that this mechanism is involved in the suppression of smoke induced B-cell infiltrates. The translation of this interaction to human COPD should now be pursued. 相似文献158.
Gabriella Ujhelyi Jeroen P van Dijk Theo W Prins Marleen M Voorhuijzen AM Angeline Van Hoef Henriek G Beenen Dany Morisset Kristina Gruden Esther J Kok 《BMC biotechnology》2012,12(1):4
Background
With the increasing number of GMOs on the global market the maintenance of European GMO regulations is becoming more complex. For the analysis of a single food or feed sample it is necessary to assess the sample for the presence of many GMO-targets simultaneously at a sensitive level. Several methods have been published regarding DNA-based multidetection. Multiplex ligation detection methods have been described that use the same basic approach: i) hybridisation and ligation of specific probes, ii) amplification of the ligated probes and iii) detection and identification of the amplified products. Despite they all have this same basis, the published ligation methods differ radically. The present study investigated with real-time PCR whether these different ligation methods have any influence on the performance of the probes. Sensitivity and the specificity of the padlock probes (PLPs) with the ligation protocol with the best performance were also tested and the selected method was initially validated in a laboratory exchange study. 相似文献159.
Moreno E; Lanne B; Vazquez AM; Kawashima I; Tai T; Fernandez LE; Karlsson KA; Angstrom J; Perez R 《Glycobiology》1998,8(7):695-705
P3 is a mouse monoclonal antibody (mAb) that binds to several NeuGc-
containing gangliosides. It also reacts with antigens expressed in human
breast tumors (Vazquez et al. (1995) Hybridoma , 14, 551-556). In this
work, the binding specificity of P3 has been characterized in more detail
using a panel of glycolipids that included several disialylated
gangliosides and several chemical derivatives of NeuGc-GM3. The carboxyl
group and the nitrogen function of sialic acid were found to play important
roles in the antibody binding, whereas the glycerol tail appears to be
nonrelevant. Molecular modeling was used to analyze the binding data,
including the finding that P3 selectively recognizes the internal NeuGc in
GD3. For this purpose, conformational studies of GD3 were performed using
molecular dynamics. It was concluded that sialic acid binds the P3 antibody
through its upper face (the one on which the carboxyl group is exposed) and
the C4-C5 side of the sugar ring, whereas none or very little contact
between the galactose residue and the protein is evident. Conformational
analysis of GD3 revealed that, despite the large flexibility of the
NeuGcalpha8NeuGc linkage, the P3 binding epitope on the external sialic
acid is not well exposed for any of the possible conformations this linkage
can adopt, whereas the internal sialic acid presents the epitope in a
proper way for several of these conformations. As a final result, a
coherent picture of the epitope that fits the wide binding data was
obtained.
相似文献
160.