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排序方式: 共有226条查询结果,搜索用时 15 毫秒
181.
Transbilayer Colocalization of Lipid Domains Explained via Measurement of Strong Coupling Parameters
Matthew?C. Blosser Aurelia?R. Honerkamp-Smith Tao Han Mikko Haataja Sarah?L. Keller 《Biophysical journal》2015,109(11):2317-2327
When micron-scale compositional heterogeneity develops in membranes, the distribution of lipids on one face of the membrane strongly affects the distribution on the other. Specifically, when lipid membranes phase separate into coexisting liquid phases, domains in each monolayer leaflet of the membrane are colocalized with domains in the opposite leaflet. Colocalized domains have never been observed to spontaneously move out of registry. This result indicates that the lipid compositions in one leaflet are strongly coupled to compositions in the opposing leaflet. Predictions of the interleaflet coupling parameter, Λ, vary by a factor of 50. We measure the value of Λ by applying high shear forces to supported lipid bilayers. This causes the upper leaflet to slide over the lower leaflet, moving domains out of registry. We find that the threshold shear stress required to deregister domains in the upper and lower leaflets increases with the inverse length of domains. We derive a simple, closed-form expression relating the threshold shear to Λ, and find Λ = 0.016 ± 0.004 kBT/nm2. 相似文献
182.
Lartigue MF Kostrzewa M Salloum M Haguenoer E Héry-Arnaud G Domelier AS Stumpf S Quentin R 《Journal of microbiological methods》2011,86(2):262-265
MALDI-TOF MS identified a 6250-Da protein specific to Sequence Type-1 (ST-1) strains and a 7625-Da protein specific to ST-17 strains when used for identification of Group B streptococci. The strains of these STs are major causes of meningitis and late-onset-disease in neonates. This rapid method of identification could thus be valuable in the evaluation of risk of neonatal diseases. 相似文献
183.
Saxena M Busca A Pandey S Kryworuchko M Kumar A 《Journal of immunology (Baltimore, Md. : 1950)》2011,187(11):5865-5878
Monocytic cells survive HIV replication and consequent cytopathic effects because of their decreased sensitivity to HIV-induced apoptosis. However, the mechanism underlying this resistance to apoptosis remains poorly understood. Lymphocytic cells are exposed to microbial products because of their translocation from the gut in persons with chronic HIV infections or following coinfections. We hypothesized that activation of monocytic cells by such microbial products through interaction with corresponding TLRs may confer antiapoptotic signals. Using HIV-viral protein R (Vpr)(52-96) peptide as a model apoptosis-inducing agent, we demonstrated that unlike monocyte-derived macrophages, undifferentiated primary human monocytes and promonocytic THP-1 cells are highly susceptible to Vpr(52-96)-induced apoptosis. Interestingly, monocytes and THP-1 cells stimulated with TLR9 agonist CpG induced almost complete resistance to Vpr(52-96)-induced apoptosis, albeit through a TLR9-independent signaling pathway. Moreover, CpG selectively induced the antiapoptotic cellular inhibitor of apoptosis (c-IAP)-2 protein and inhibition of the c-IAP-2 gene by either specific small interfering RNA or synthetic second mitochondrial activator of caspases mimetic reversed CpG-induced resistance against Vpr(52-96)-mediated apoptosis. We demonstrated that c-IAP-2 is regulated by the JNK and calcium signaling pathway, in particular calmodulin-dependent protein kinase-II. Furthermore, inhibition of JNK and the calcium signaling including the calmodulin-dependent protein kinase-II by either pharmacological inhibitors or their specific small interfering RNAs reversed CpG-induced protection against Vpr(52-96)-mediated apoptosis. We also show that CpG induced JNK phosphorylation through activation of the calcium signaling pathway. Taken together, our results suggest that CpG-induced protection may be mediated by c-IAP-2 through the calcium-activated JNK pathway via what appeared to be TLR9-independent signaling pathways. 相似文献
184.
185.
Romain Dassonneville Aurelia Baur Sébastien Fritz Didier Boichard Vincent Ducrocq 《遗传、选种与进化》2012,44(1):40
Background
Today, genomic evaluations are an essential feature of dairy cattle breeding. Initially, genomic evaluation targeted young bulls but recently, a rapidly increasing number of females (both heifers and cows) are being genotyped. A rising issue is whether and how own performance of genotyped cows should be included in genomic evaluations. The purpose of this study was to assess the impact of including yield deviations, i.e. own performance of cows, in genomic evaluations.Methods
Two different genomic evaluations were performed: one including only reliable daughter yield deviations of proven bulls based on their non-genotyped daughters, and one including both daughter yield deviations for males and own yield deviations for genotyped females. Milk yield, the trait most prone to preferential treatment, and somatic cell count, for which such a bias is very unlikely, were studied. Data consisted of two groups of animals from the three main dairy breeds in France: 11 884 elite females genotyped by breeding companies and 7032 cows genotyped for a research project (and considered as randomly selected from the commercial population).Results
For several measures that could be related to preferential treatment bias, the elite group presented a different pattern of estimated breeding values for milk yield compared to the other combinations of trait and group: for instance, for milk yield, the average difference between estimated breeding values with or without own yield deviations was significantly different from 0 for this group. Correlations between estimated breeding values with or without yield deviations were lower for elite females than for randomly selected cows for milk yield but were very similar for somatic cell count.Conclusions
This study demonstrated that including own milk performance of elite females leads to biased (over-estimated) genomic evaluations. Thus, milk production records of elite cows require specific treatment in genomic evaluation. 相似文献186.
KRAS, BRAF, and PI3KCA are the most frequently mutated oncogenes in human colon cancer. To explore their effects on morphogenesis, we used the colon cancer-derived cell line Caco-2. When seeded in extracellular matrix, individual cells proliferate and generate hollow, polarized cysts. The expression of oncogenic phosphatidylinositol 3-kinase (PI3KCA H1047R) in Caco-2 has no effect, but K-Ras V12 or B-Raf V600E disrupts polarity and tight junctions and promotes hyperproliferation, resulting in large, filled structures. Inhibition of mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase blocks the disruption of morphology, as well as the increased levels of c-myc protein induced by K-Ras V12 and B-Raf V600E. Apical polarity is already established after the first cell division (two-cell stage) in Caco-2 three-dimensional cultures. This is disrupted by expression of K-Ras V12 or B-Raf V600E but can be rescued by ribonucleic acid interference-mediated depletion of c-myc. We conclude that ERK-mediated up-regulation of c-myc by K-Ras or B-Raf oncogenes disrupts the establishment of apical/basolateral polarity in colon epithelial cells independently of its effect on proliferation. 相似文献
187.
188.
Technologies to synthetically assemble chromosome sized fragments of DNA as well as to enable making thousands of simultaneous changes to existing genomes are now available. These capacities are collectively termed synthetic genomics. The implications of synthetic genomics extend beyond the limited pathway and gene engineering of the past to include the engineering or whole metabolisms, regulatory networks, and even ecosystems. However, in order for those potentials to be met, certain limitations and barriers must be overcome. These barriers no longer include DNA modification and assembly, but instead are based in the limited organisms that many synthetic genomics methods function in, and the limited software for designing custom genomic sequences. 相似文献
189.
Guo W Keckesova Z Donaher JL Shibue T Tischler V Reinhardt F Itzkovitz S Noske A Zürrer-Härdi U Bell G Tam WL Mani SA van Oudenaarden A Weinberg RA 《Cell》2012,148(5):1015-1028
190.
Staphylococcus aureus Transcriptome Architecture: From Laboratory to Infection-Mimicking Conditions 总被引:1,自引:0,他引:1
Ulrike M?der Pierre Nicolas Maren Depke Jan Pané-Farré Michel Debarbouille Magdalena M. van der Kooi-Pol Cyprien Guérin Sandra Dérozier Aurelia Hiron Hanne Jarmer Aurélie Leduc Stephan Michalik Ewoud Reilman Marc Schaffer Frank Schmidt Philippe Bessières Philippe Noirot Michael Hecker Tarek Msadek Uwe V?lker Jan Maarten van Dijl 《PLoS genetics》2016,12(4)