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Bacterial cell division commences with the assembly of the tubulin-like protein, FtsZ, at midcell to form a ring. Division site selection in rod-shaped bacteria is mediated by MinC and MinD, which form a division inhibitor. Bacillus subtilis DivIVA protein ensures that MinCD specifically inhibits division close to the cell poles, while allowing division at midcell. We have examined the localization of MinC protein and show that it is targeted to midcell and retained at the mature cell poles. This localization is reminiscent of the pattern previously described for MinD. Localization of MinC requires both early (FtsZ) and late (PbpB) division proteins, and it is completely dependent on MinD. The effects of a divIVA mutation on localization of MinC now suggest that the main role of DivIVA is to retain MinCD at the cell poles after division, rather than recruitment to nascent division sites. By overexpressing minC or minD, we show that both proteins are required to block division, but that only MinD needs to be in excess of wild-type levels. The results suggest a mechanism whereby MinD is required both to pilot MinC to the cell poles and to constitute a functional division inhibitor. 相似文献
94.
Luciano Antolini Adele Mucci Francesca Parenti Gavino Sanna Chiara Zanardi 《Inorganica chimica acta》2005,358(11):3033-3040
Palladium(II) complexes with two thiophene derivatives bearing alkylsulfanyl chains, i.e., 3-(n-butylsulfanyl)thiophene and 4,4′-bis(n-butylsulfanyl)-2,2′-bithiophene, are synthesised and spectroscopically and electrochemically characterised. The molecular structure of PdCl2[3-(n-butylsulfanyl)thiophene]2 was determined by X-ray analysis. The properties of the complexes have been compared with those of PdCl2[3,3′-bis(n-butylsulfanyl)-2,2′-bithiophene] and of a conductive polymer partially coordinated with Pd(II), previously synthesised by us. We found that Pd(II) ions can coordinate sulfanyl sulfur atoms both in cis and trans configuration, leading to a reticulate material, where some kind of interchain bridging may be reasonably supposed to enhance the bulk conductivity. 相似文献
95.
Integral membrane proteins perform crucial cellular functions and are the targets for the majority of pharmaceutical agents. However, the hydrophobic nature of their membrane-embedded domains makes them difficult to work with. Here, we describe a shotgun proteomic method for the high-throughput analysis of the membrane-embedded transmembrane domains of integral membrane proteins which extends the depth of coverage of the membrane proteome. 相似文献
96.
Protective immunity against viral pathogens depends on the generation and maintenance of a small population of memory CD8(+) T cells. Successful memory cell generation begins with early interactions between na?ve T cell and dendritic cells (DCs) within the inflammatory milieu of the secondary lymphoid tissues. Recent insights into the role of different populations of DCs, and kinetics of antigen presentation, during viral infections have helped to understand how DCs can shape the immune response. Here, we review the recent progress that has been made towards defining how specific DC subsets drive effector CD8(+) T-cell expansion and differentiation into memory cells. Further, we endeavour to examine how the molecular signals imparted by DCs coordinate to generate protective CD8(+) T-cell immunity. 相似文献
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98.
Hall T Leone JW Wiese JF Griggs DW Pegg LE Pauley AM Tomasselli AG Zack MD 《Bioscience reports》2009,29(4):217-228
Members of the ADAM (a disintegrin and metalloproteinase) family of proteins possess a multidomain architecture which permits functionalities as adhesion molecules, signalling intermediates and proteolytic enzymes. ADAM8 is found on immune cells and is induced by multiple pro-inflammatory stimuli suggesting a role in inflammation. Here we describe an activation mechanism for recombinant human ADAM8 that is independent from classical PC (pro-protein convertase)-mediated activation. N-terminal sequencing revealed that, unlike other ADAMs, ADAM8 undergoes pre-processing at Glu(158), which fractures the Pro (pro-segment)-domain before terminal activation takes place to remove the putative cysteine switch (Cys(167)). ADAM8 lacking the DIS (disintegrin) and/or CR (cysteine-rich) and EGF (epidermal growth factor) domains displayed impaired ability to complete this event. Thus pre-processing of the Pro-domain is co-ordinated by DIS and CR/EGF domains. Furthermore, by placing an EK (enterokinase) recognition motif between the Pro- and catalytic domains of multiple constructs, we were able to artificially remove the pro-segment prior to pre-processing. In the absence of pre-processing of the Pro-domain a marked decrease in specific activity was observed with the autoactivated enzyme, suggesting that the Pro-domain continued to associate and inhibit active enzyme. Thus, pre-processing of the Pro-domain of human ADAM8 is important for enzyme maturation by preventing re-association of the pro-segment with the catalytic domain. Given the observed necessity of DIS and CR/EGF for pre-processing, we conclude that these domains are crucial for the proper activation and maturation of human ADAM8. 相似文献
99.
Adele L. Marston 《Current biology : CB》2009,19(2):R74-R76
100.
Gulay Mann Simon Diffey Brian Cullis Fermin Azanza David Martin Alison Kelly Lynne McIntyre Adele Schmidt Wujun Ma Zena Nath Ibrahim Kutty P. Emmett Leyne Lynette Rampling Ken J. Quail Matthew K. Morell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(8):1519-1537
While the genetic control of wheat processing characteristics such as dough rheology is well understood, limited information
is available concerning the genetic control of baking parameters, particularly sponge and dough (S&D) baking. In this study,
a quantitative trait loci (QTL) analysis was performed using a population of doubled haploid lines derived from a cross between
Australian cultivars Kukri × Janz grown at sites across different Australian wheat production zones (Queensland in 2001 and
2002 and Southern and Northern New South Wales in 2003) in order to examine the genetic control of protein content, protein
expression, dough rheology and sponge and dough baking performance. The study highlighted the inconsistent genetic control
of protein content across the test sites, with only two loci (3A and 7A) showing QTL at three of the five sites. Dough rheology
QTL were highly consistent across the 5 sites, with major effects associated with the Glu-B1 and Glu-D1 loci. The Glu-D1 5 + 10 allele had consistent effects on S&D properties across sites; however, there was no evidence for a positive effect
of the high dough strength Glu-B1-al allele at Glu-B1. A second locus on 5D had positive effects on S&D baking at three of five sites. This study demonstrated that dough rheology
measurements were poor predictors of S&D quality. In the absence of robust predictive tests, high heritability values for
S&D demonstrate that direct selection is the current best option for achieving genetic gain in this product category.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献