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31.
Mandy M Cox Sherryll L Layton Tieshan Jiang Kim Cole Billy M Hargis Luc R Berghman Walter G Bottje Young Min Kwon 《BMC biotechnology》2007,7(1):59
Background
A variety of techniques have been described which introduce scarless, site-specific chromosomal mutations. These techniques can be applied to make point mutations or gene deletions as well as insert heterologous DNA into bacterial vectors for vaccine development. Most methods use a multi-step approach that requires cloning and/or designing repeat sequences to facilitate homologous recombination. We have modified previously published techniques to develop a simple, efficient PCR-based method for scarless insertion of DNA into Salmonella enteritidis chromosome. 相似文献32.
Ward Delphi Melbourne-Thomas Jessica Pecl Gretta T. Evans Karen Green Madeline McCormack Phillipa C. Novaglio Camilla Trebilco Rowan Bax Narissa Brasier Madeleine J. Cavan Emma L. Edgar Graham Hunt Heather L. Jansen Jan Jones Russ Lea Mary-Anne Makomere Reuben Mull Chris Semmens Jayson M. Shaw Janette Tinch Dugald van Steveninck Tatiana J. Layton Cayne 《Reviews in Fish Biology and Fisheries》2022,32(1):65-100
Reviews in Fish Biology and Fisheries - Marine ecosystems and their associated biodiversity sustain life on Earth and hold intrinsic value. Critical marine ecosystem services include maintenance of... 相似文献
33.
Bax Narissa Novaglio Camilla Maxwell Kimberley H. Meyers Koen McCann Joy Jennings Sarah Frusher Stewart Fulton Elizabeth A. Nursey-Bray Melissa Fischer Mibu Anderson Kelli Layton Cayne Emad Gholam Reza Alexander Karen A. Rousseau Yannick Lunn Zau Carter Chris G. 《Reviews in Fish Biology and Fisheries》2022,32(1):189-207
Reviews in Fish Biology and Fisheries - Humans have relied on coastal resources for centuries. However, current growth in population and increased accessibility of coastal resources through... 相似文献
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35.
Levoglucosan is a major product of biomass pyrolysis. While this pyrolyzed biomass, also known as bio-oil, contains sugars that are an attractive fermentation substrate, commonly-used biocatalysts, such as Escherichia coli, lack the ability to metabolize this anhydrosugar. It has previously been shown that recombinant expression of the levoglucosan kinase enzyme enables use of levoglucosan as carbon and energy source. Here, ethanologenic E. coli KO11 was engineered for levoglucosan utilization by recombinant expression of levoglucosan kinase from Lipomyces starkeyi. Our engineering strategy uses a codon-optimized gene that has been chromosomally integrated within the pyruvate to ethanol (PET) operon and does not require additional antibiotics or inducers. Not only does this engineered strain use levoglucosan as sole carbon source, but it also ferments levoglucosan to ethanol. This work demonstrates that existing biocatalysts can be easily modified for levoglucosan utilization. 相似文献
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37.
Chattopadhyay D Carey AJ Caliot E Webb RI Layton JR Wang Y Bohnsack JF Adderson EE Ulett GC 《Microbes and infection / Institut Pasteur》2011,13(4):369-382
Opsonin-independent phagocytosis of Group B Streptococcus (GBS) is important in defense against neonatal GBS infections. A recent study indicated a role for GBS pilus in macrophage phagocytosis (Maisey et al Faseb J 22 2008 1715-24). We studied 163 isolates from different phylogenetic backgrounds and those possessing or lacking the gene encoding the pilus backbone protein, Spb1 (SAN1518, PI-2b) and spb1-deficient mutants of wild-type (WT) serotype III-3 GBS 874391 in non-opsonic phagocytosis assays using J774A.1 macrophages. Numbers of GBS phagocytosed differed up to 23-fold depending on phylogenetic background; isolates possessing spb1 were phagocytosed more than isolates lacking spb1. Comparing WT GBS and isogenic spb1-deficient mutants showed WT was phagocytosed better compared to mutants; Spb1 also enhanced intracellular survival as mutants were killed more efficiently. Complementation of mutants restored phagocytosis and resistance to killing in J774A.1 macrophages. Spb1 antiserum revealed surface expression in WT GBS and spatial distribution relative to capsular polysaccharide. spb1 did not affect macrophage nitric oxide and TNF-alpha responses; differences in phagocytosis did not correlate with N-acetyl d-glucosamine (from GBS cell-wall) according to enzyme-linked lectin-sorbent assay. Together, these findings support a role for phylogenetic lineage and Spb1 in opsonin-independent phagocytosis and intracellular survival of GBS in J774A.1 macrophages. 相似文献
38.
Background
PCR-based surveys have shown that guppies (Poecilia reticulata) have an unusually large visual-opsin gene repertoire. This has led to speculation that opsin duplication and divergence has enhanced the evolution of elaborate male coloration because it improves spectral sensitivity and/or discrimination in females. However, this conjecture on evolutionary connections between opsin repertoire, vision, mate choice, and male coloration was generated with little data on gene expression. Here, we used RT-qPCR to survey visual-opsin gene expression in the eyes of males, females, and juveniles in order to further understand color-based sexual selection from the perspective of the visual system. 相似文献39.
Layton AT 《Mathematical biosciences》2005,197(2):211-230
The organization of tubules and blood vessels in the quail medullary cone is highly structured. This structural organization may result in preferential interactions among tubules and vessels, interactions that may enhance urine concentrating capability. In this study, we formulate a model framework for the urine concentrating mechanism of the quail kidney. The model simulates preferential interactions among renal tubules by representing two concentric cores and by specifying the fractions of tubules assigned to each of the concentric cores. The model equations are based on standard expressions for transmural transport and on solute and water conservation. Model results suggest that the preferential interactions among tubules enhance the urine concentration capacity of short medullary cones by reducing the diluting effect of the descending limbs on the region of the interstitium where the collecting ducts are located; however, the effects on longer cones are unclear. 相似文献
40.
Layton BE Sastry AM Wang H Sullivan KA Feldman EL Komorowski TE Philbert MA 《Journal of biomechanics》2004,37(6):879-888
Both structural and functional differences between normal and diabetic nerve have been observed, in human patients and animal models. We hypothesize that these structural differences are quantifiable, morphologically and mechanically, with the ultimate aim of understanding the contribution of these differences to permanent nerve damage. The outer collagenous epineurial and perineurial tissues of mammalian peripheral nerves mechanically and chemically shield the conducting axons. We have quantified differences in these collagens, using whole-nerve uniaxial testing, and immunohistochemistry of collagens type I, III, and IV in diabetic and normal nerves. We present results of two studies, on normal and diabetic BioBreeding (BB), and normal, diabetic and weight-controlled Sprague-Dawley (SD) rats, respectively. Overall, we measured slightly higher uniaxial moduli (e.g. 5.9 MPa vs. 3.5 MPa, BB; 10.7 MPa vs. 10.0 MPa, SD at 40% strain) in whole nerves as well as higher peak stresses (e.g. 0.99 MPa vs. 0.74 MPa, BB; 2.16 MPa vs. 1.94 MPa, SD at 40% strain) in the diabetics of both animal models. We measured increased concentrations of types III and IV collagens in the diabetics of both models and mixed upregulation results were observed in type I protein levels. We detected small differences in mechanical properties at the tissue scale, though we found significant structural and morphometric differences at the fibril scale. These findings suggest that whole-tissue mechanical testing is not a sufficient assay for collagen glycation, and that fibrillar and molecular scale assays are needed to detect the earliest stages of diabetic protein glycation. 相似文献