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排序方式: 共有272条查询结果,搜索用时 13 毫秒
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Sarah E. Stewart Stephanie C. Kondos Antony Y. Matthews Michael E. D'Angelo Michelle A. Dunstone James C. Whisstock Joseph A. Trapani Phillip I. Bird 《The Journal of biological chemistry》2014,289(13):9172-9181
Cytotoxic lymphocytes eliminate virally infected or neoplastic cells through the action of cytotoxic proteases (granzymes). The pore-forming protein perforin is essential for delivery of granzymes into the cytoplasm of target cells; however the mechanism of this delivery is incompletely understood. Perforin contains a membrane attack complex/perforin (MACPF) domain and oligomerizes to form an aqueous pore in the plasma membrane; therefore the simplest (and best supported) model suggests that granzymes passively diffuse through the perforin pore into the cytoplasm of the target cell. Here we demonstrate that perforin preferentially delivers cationic molecules while anionic and neutral cargoes are delivered inefficiently. Furthermore, another distantly related pore-forming MACPF protein, pleurotolysin (from the oyster mushroom), also favors the delivery of cationic molecules, and efficiently delivers human granzyme B. We propose that this facilitated diffusion is due to conserved features of oligomerized MACPF proteins, which may include an anionic lumen. 相似文献
44.
JC. Brisset F. Gazeau C. Corot N. Nighoghossian Y. Berthezène E. Canet-Soulas M. Wiart 《IRBM》2018,39(2):93-102
Background
Inflammation is a share process in atherosclerosis and stroke and is thought to be a key player in the evolution of these diseases. Ten years ago, inflammation imaging with magnetic resonance imaging (MRI) was considered very promising for both pre-clinical and clinical studies of atherosclerosis and stroke.Contribution
We report here contributions to the field of inflammation imaging with USPIO-enhanced MRI. The goal was to investigate the life cycle of USPIOs in the body, and how the MRI signal has been impacted during their bio-interactions and bioprocessing. Those mechanisms were applied to pre-clinical longitudinal studies of inflammation in atherosclerosis and at the acute stage of ischemic stroke thus allowing the monitoring of treatment effects.Conclusion
This review presents the contribution of the collaborative research project under the “TecSan” grant from the French Research Agency (ANR) as well as pre-clinical and clinical perspectives of USPIO's inflammation MRI in atherosclerosis and stroke. 相似文献45.
Nonneutral evolution of tandem repeats in the mitochondrial DNA control region of lagomorphs 总被引:7,自引:0,他引:7
Casane D; Dennebouy N; de Rochambeau H; Mounolou JC; Monnerot M 《Molecular biology and evolution》1997,14(8):779-789
The mitochondrial DNA of the European rabbit (Oryctolagus cuniculus)
contains a tandem array of 153-bp repeats in the vicinity of the
replication origin of the H-stand. Variation among molecules in the number
of these repeats results in inter- and intraindividual length polymorphism
(heteroplasmy). Generally, in an individual, one predominant molecular type
is observed, the others representing a low percentage of the mtDNA content.
At the tissue level, we observe a particular distribution of this
polymorphism in the gonads compared with liver, kidneys, or brain, implying
a relationship between the differentiation status of the cells and the
types of new mtDNA molecules which appear and accumulate during lifetime.
Similar tandem repeats were also found in the mtDNA noncoding region of
European hares (Lepus europaeus), a cottontail (Sylvilagus floridanus), and
a pika (Ochotona rufescens). The lengths and the sequences of these units
evolve rapidly and in a concerted way, but the number of repeats is
maintained in a narrow range, and an internal 20-bp segment is highly
conserved. Constraints restrict the evolution of the primary sequence of
these repeated units, the number of which is probably controlled by a
stabilizing selection.
相似文献
46.
Distinguishing morphologically cryptic taxa, by definition, requires genetic data such as DNA sequences. However, DNA sequences may not be obtained easily for taxa from remote sites. Here we provide the details of a high-resolution melt-curve-based method using taxon-specific primers that can distinguish two taxa of Adélie penguins, and that will be usable in Antarctica when combined with some of the newly developed field-deployable thermal cyclers. We suggest that the wider adoption of field-deployable polymerase-chain-reaction-based techniques will enable faster assignation of haplotype to individuals in situ, and so allow the targeting of observations and sample collection to specimens relevant to the research question. Targeting individuals will also reduce the need to repeatedly handle animals and reduce the time and travel required to complete field work. 相似文献
47.
P T Gomme P E Thompson J Whisstock P G Stanton M T Hearn 《The journal of peptide research》1999,54(3):218-229
This investigation describes the design, synthesis and evaluation of chimeric peptides related to the bovine thyrotropin beta-subunit, bTSHbeta. The structures of these chimeric peptides were derived from investigations with linear peptides and sequence alignment studies, in association with a homology model of TSHbeta developed from the hCG X-ray crystallographic structure. The structures of these chimeric peptides comprised beta-turn regions of loop L1 [bTSHbeta(14-20)] and loop L3 [bTSHbeta(65-72)] held in close proximity by a bis-beta-alanine linker and the disulfide bond bTSHbeta[Cys16-Cys67]. Linear and cyclic chimeric peptides were evaluated in immunochemical assays for their ability to inhibit the binding of radio-iodinated bTSHbeta [125I-bTSHbeta] to the monoclonal antibodies, mAb279 and mAb299. Previously, mAb279 and mAb299 have been shown to recognize epitopes accessible on the surface of TSHbeta that lie in close proximity to the TSH receptor-binding site. The results indicate that these chimeric peptides can specifically inhibit in a dose-dependent manner the binding of 125I-bTSHbeta to mAb299, while having a lesser effect on the binding with mAb279. Based on these results, it can be concluded that the bTSHbeta-epitope recognized by mAb299 involves contributions from amino residues from the beta-turn regions of the L1 and L3 loops of TSHbeta, and that these loop regions flank part of the receptor binding site of the bTSH beta-subunit. 相似文献
48.
Gomme Peter T. Thompson Philip E. Whisstock James Stanton Peter G. Hearn Milton T. W. 《International journal of peptide research and therapeutics》1999,6(2-3):185-192
Summary In this investigation, an overlapping set of synthetic peptides spanning the entire primary structures of the β-subunit of
bovine and human thyrotropin, bTSHβ and hTSHβ respectively, have been prepared to aid the delineation of the amino acid sequence
regions involved in two spatially related epitopes of bTSH. These peptides were then evaluated for their ability to inhibit
the binding of two anti-hTSH monoclonal antibodies, designated mAb279 and mAb299, to radiolabeled I125-bTSHβ using competitive radioimmunoassay procedures. Synthetic peptides related to the sequence region b/hTSHβ[56–68] were
found to specifically inhibit the binding of I125-bTSHβ to mAb299, whilst having no effect on the binding of mAb279. In previous studies we have shown that mAb279 and mAb299
recognise epitopic sites located within the receptor-binding site of the TSH β-subunit. This investigation has therefore permitted
identification of a contribution to the receptor binding site from the TSHβ[56–68] sequence, which forms part of theL3 loop region of the TSH β-subunit that is held in close proximity to theL1 loop region and the C-terminus of the TSH β-subunit by the disulphide bonds TSHβ[Cys16-Cys67] and TSHβ[Cys19-Cys105]. This finding is in agreement with previous investigations which have shown that TSHβ[Tyr59] and TSHβ[Tyr74] are also associated with the mAb299 epitope site, as well as contributing to the receptor binding region of the TSH β-subunit. 相似文献
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Rupert CM Jones Maria Dickson-Spillmann Martin JC Mather Dawn Marks Bryanie S Shackell 《Respiratory research》2008,9(1):62