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71.
Levitskiy SA Sycheva AM Kharlampieva DD Oberto J Kamashev DE Serebryakova MV Moshkovskii SA Lazarev VN Govorun VM 《Biochimie》2011,93(7):1102-1109
HU is a most abundant DNA-binding protein in bacteria. This protein is conserved either in its heterodimeric form or in one of its homodimeric forms in all bacteria, in plant chloroplasts, and in some viruses. HU protein non-specifically binds and bends DNA as a hetero- or homodimer and can participate in DNA supercoiling and DNA condensation. It also takes part in some DNA functions such as replication, recombination, and repair. HU does not recognize any specific sequences but shows some specificity to cruciform DNA and to repair intermediates, e.g., nick, gap, bulge, 3′-overhang, etc. To understand the features of HU binding to DNA and repair intermediates, a fast and easy HU proteins purification procedure is required. Here we report overproduction and purification of the HU homodimers. The method of HU purification allows obtaining a pure recombinant non-tagged protein cloned in Escherichia coli. We applied this method for purification of Acholeplasma laidlawii HU and demonstrated that this protein possesses a DNA - binding activity and is free of contaminating nuclease activity. Besides that we have shown that expression of A. laidlawii ihf_hu gene in a slow-growing hupAB E. coli strain restores the wild-type growth indicating that aclHU can perform the basic functions of E. coli HU in vivo. 相似文献
72.
Cattaneo F Iaccio A Guerra G Montagnani S Ammendola R 《Free radical biology & medicine》2011,51(6):1126-1136
Cross talk between unrelated cell surface receptors, such as G-protein-coupled receptors (GPCR) and receptor tyrosine kinases (RTK), is a crucial signaling mechanism to expand the cellular communication network. We investigated the ability of the GPCR formyl peptide receptor-like 1 (FPRL1) to transactivate the RTK epidermal growth factor receptor (EGFR) in CaLu-6 cells. We observed that stimulation with WKYMVm, an FPRL1 agonist isolated by screening synthetic peptide libraries, induces EGFR tyrosine phosphorylation, p47phox phosphorylation, NADPH-oxidase-dependent superoxide generation, and c-Src kinase activity. As a result of EGFR transactivation, phosphotyrosine residues provide docking sites for recruitment and triggering of the STAT3 pathway. WKYMVm-induced EGFR transactivation is prevented by the FPRL1-selective antagonist WRWWWW, by pertussis toxin (PTX), and by the c-Src inhibitor PP2. The critical role of NADPH-oxidase-dependent superoxide generation in this cross-talk mechanism is corroborated by the finding that apocynin or a siRNA against p22phox prevents EGFR transactivation and c-Src kinase activity. In addition, WKYMVm promotes CaLu-6 cell growth, which is prevented by PTX and by WRWWWW. These results highlight the role of FPRL1 as a potential target of new drugs and suggest that targeting both FPRL1 and EGFR may yield superior therapeutic effects compared with targeting either receptor separately. 相似文献
73.
Rodrigo Ivan Prim Marcos André Sch?rner Simone Gon?alves Senna Christiane Louren?o Nogueira Anna Carolina Can?ado Figueiredo Jaquelline Germano de Oliveira Darcita Bürger Rovaris Maria Luiza Bazzo 《Memórias do Instituto Oswaldo Cruz》2015,110(5):618-623
Drug resistance is a global threat and one of the main contributing factors to
tuberculosis (TB) outbreaks. The goal of this study was to analyse the molecular
profile of multidrug-resistant TB (MDR-TB) in the state of Santa Catarina in southern
Brazil. Fifty-three MDR Mycobacterium tuberculosisclinical isolates
were analysed by spoligotyping and a partial region of therpoB gene,
which is associated with rifampicin resistance (RMP-R), was sequenced. Some isolates
were also distinguished by their mycobacterial interspersed repetitive units (MIRU).
S531L was the most prevalent mutation found within rpoB in RMP-R
isolates (58.5%), followed by S531W (20.8%). Only two MDR isolates showed no
mutations withinrpoB. Isolates of the Latin American Mediterranean
(LAM) family were the most prevalent (45.3%) found by spoligotyping, followed by
Haarlem (9.4%) and T (7.5%) families. SIT106 was found in 26.4% of isolates and all
SIT106 isolates typed by MIRU-12 (5 out of 14) belong to MIT251. There was a high
correlation between the S531W mutation and the LAM family mainly because all SIT2263
(LAM9) isolates carry this mutation. Among isolates with the S531W mutation in
rpoB MIRU demonstrates a cluster formed by four isolates (SIT2263
and MIT163) and very similar profiles were observed between eight of the nine
isolates. Better characterisation of TB isolates may lead to new ways in which to
control and treat TB in this region of Brazil. 相似文献
74.
Letícia Muraro Wildner Maria Luiza Bazzo Susie Coutinho Liedke Christiane Louren?o Nogueira Gabriela Segat Simone Gon?alves Senna Aline Daiane Schlindwein Jaquelline Germano de Oliveira Darcita B Rovaris Claudio A Bonjardim Erna G Kroon Paulo CP Ferreira 《Memórias do Instituto Oswaldo Cruz》2014,109(3):356-361
The identification of mycobacteria is essential because tuberculosis (TB) and
mycobacteriosis are clinically indistinguishable and require different therapeutic
regimens. The traditional phenotypic method is time consuming and may last up to 60
days. Indeed, rapid, affordable, specific and easy-to-perform identification methods
are needed. We have previously described a polymerase chain reaction-based method
called a mycobacteria mobility shift assay (MMSA) that was designed for
Mycobacterium tuberculosis complex (MTC) and nontuberculous mycobacteria
(NTM) species identification. The aim of this study was to assess the MMSA for the
identification of MTC and NTM clinical isolates and to compare its performance with
that of the PRA-hsp65 method. A total of 204 clinical isolates (102
NTM and 102 MTC) were identified by the MMSA and PRA-hsp65. For
isolates for which these methods gave discordant results, definitive species
identification was obtained by sequencing fragments of the 16S rRNA and
hsp65 genes. Both methods correctly identified all MTC isolates. Among
the NTM isolates, the MMSA alone assigned 94 (92.2%) to a complex or species, whereas
the PRA-hsp65 method assigned 100% to a species. A 91.5% agreement
was observed for the 94 NTM isolates identified by both methods. The MMSA provided
correct identification for 96.8% of the NTM isolates compared with 94.7% for
PRA-hsp65. The MMSA is a suitable auxiliary method for routine
use for the rapid identification of mycobacteria. 相似文献
75.
In Bacillus subtilis separate sets of genes are implicated in the transport and metabolism of the amino sugars, glucosamine and N‐acetylglucosamine. The genes for use of N‐acetylglucosamine (nagAB and nagP) are found in most firmicutes and are controlled by a GntR family repressor NagR (YvoA). The genes for use of glucosamine (gamAP) are repressed by another GntR family repressor GamR (YbgA). The gamR‐gamAP synton is only found in B. subtilis and a few very close relatives. Although NagR and GamR are close phylogenetically, there is no cross regulation between their operons. GlcN6P prevents all binding of GamR to its targets. NagR binds specifically to targets containing the previously identified dre palindrome but its binding is not inhibited by GlcN6P or GlcNAc6P. GamR‐like binding sites were also found in some other Bacilli associated with genes for use of chitin, the polymer of N‐acetylglucosamine, and with a gene for another GamR homologue (yurK). We show that GamR can bind to two regions in the chi operon of B. licheniformis and that GamR and YurK are capable of heterologous regulation. GamR can repress the B. licheniformis licH‐yurK genes and YurK can repress B. subtilis gamA. 相似文献
76.
Marc Srour Germano Leão Demolin Leite Torsten Wappler Teja Tscharntke Christoph Scherber 《Insect Science》2012,19(6):705-705
Retraction: The following article from Insect Science, ‘Diversity of ants across an altitudinal gradient in and outside a spruce forest in the Harz Mountains, Germany’ by Marc Srour, Germano Leão Demolin Leite, Torsten Wappler, Teja Tscharntke and Christoph Scherber, published online on 2 August 2012 in Wiley Online Library ( http://wileyonlinelibrary.com ), has been retracted by agreement between the authors, the journal Editor in Chief, Le Kang, and Wiley Publishing Asia Pty Ltd. The retraction has been agreed due to concerns having been raised about the validity of the species richness values derived by the authors, and regarding the validity of the species determinations. 相似文献
77.
Background
RNA silencing occurs in a broad range of organisms. Although its ancestral function is probably related to the genome defense mechanism against repetitive selfish elements, it has been found that RNA silencing regulates different cellular processes such as gene expression and chromosomal segregation. In Neurospora crassa, a RNA silencing mechanism, called quelling, acts to repress the expression of transgenes and transposons, but until now no other cellular functions have been shown to be regulated by this mechanism. 相似文献78.
Cappelli A Giuliani G Valenti S Anzini M Vomero S Giorgi G Sogliano C Maciocco E Biggio G Concas A 《Bioorganic & medicinal chemistry》2008,16(6):3428-3437
The exploration of the structure-affinity relationships concerning a new class of peripheral benzodiazepine receptor (PBR) ligands related to alpidem has been pursued in order to evaluate the consistency of the structure-affinity relationships among different classes (and subclasses) of PBR ligands. The target amide derivatives were prepared following a previously published procedure based on the condensation of pyrrolo[3,4-b]quinoline derivatives 11a,b with glyoxylic acid mono-hydrate and the subsequent amidation of the acids obtained via mixed anhydride. On the other hand, the preparation of compound 9g lacking the pharmacophoric (delta1) carbonyl group involved: (a) the double sequential attack of the dimethylmethyleneammonium salt obtained from bis(dimethylamino)methane and acetyl chloride to pyrrolo[3,4-b]quinoline derivative 11b, (b) the quaternization of the obtained allylamine derivative 13 with methyl iodide, and (c) the palladium-catalyzed allylation of N-methyl-p-anisidine by quaternary allylammonium cation 14. The structure-affinity relationship trends observed in this subclass of tricyclic alpidem-related PBR ligands find correlations in other classes (or subclasses) of PBR ligands. This result supports the initial pharmacophoric hypothesis and suggests a common mode of interaction at the PBR binding site. 相似文献
79.
80.
Roberto Würth Federica Barbieri Alessandra Pattarozzi Germano Gaudenzi Federico Gatto Pietro Fiaschi Jean-Louis Ravetti Gianluigi Zona Antonio Daga Luca Persani Diego Ferone Giovanni Vitale Tullio Florio 《Molecular neurobiology》2017,54(7):4879-4895
The presence and functional role of tumor stem cells in benign tumors, and in human pituitary adenomas in particular, is a debated issue that still lacks a definitive formal demonstration. Fifty-six surgical specimens of human pituitary adenomas were processed to establish tumor stem-like cultures by selection and expansion in stem cell-permissive medium or isolating CD133-expressing cells. Phenotypic and functional characterization of these cells was performed (1) ex vivo, by immunohistochemistry analysis on paraffin-embedded tissues; (2) in vitro, attesting marker expression, proliferation, self-renewal, differentiation, and drug sensitivity; and (3) in vivo, using a zebrafish model. Within pituitary adenomas, we identified rare cell populations expressing stem cell markers but not pituitary hormones; we isolated and expanded in vitro these cells, obtaining fibroblast-free, stem-like cultures from 38 pituitary adenoma samples. These cells grow as spheroids, express stem cell markers (Oct4, Sox2, CD133, and nestin), show sustained in vitro proliferation as compared to primary cultures of differentiated pituitary adenoma cells, and are able to differentiate in hormone-expressing pituitary cells. Besides, pituisphere cells, apparently not tumorigenic in mice, engrafted in zebrafish embryos, inducing pro-angiogenic and invasive responses. Finally, pituitary adenoma stem-like cells express regulatory pituitary receptors (D2R, SSTR2, and SSTR5), whose activation by a dopamine/somatostatin chimeric agonist exerts antiproliferative effects. In conclusion, we provide evidence that human pituitary adenomas contain a subpopulation fulfilling biological and phenotypical signatures of tumor stem cells that may represent novel therapeutic targets for therapy-resistant tumors. 相似文献