全文获取类型
收费全文 | 142篇 |
免费 | 4篇 |
专业分类
146篇 |
出版年
2020年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 10篇 |
2009年 | 5篇 |
2008年 | 12篇 |
2007年 | 5篇 |
2006年 | 8篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有146条查询结果,搜索用时 15 毫秒
81.
Kriebel M Metzger J Trinks S Chugh D Harvey RJ Harvey K Volkmer H 《The Journal of biological chemistry》2011,286(27):24385-24393
Cell adhesion molecules regulate synapse formation and maintenance via transsynaptic contact stabilization involving both extracellular interactions and intracellular postsynaptic scaffold assembly. The cell adhesion molecule neurofascin is localized at the axon initial segment of granular cells in rat dentate gyrus, which is mainly targeted by chandelier cells. Lentiviral shRNA-mediated knockdown of neurofascin in adult rat brain indicates that neurofascin regulates the number and size of postsynaptic gephyrin scaffolds, the number of GABA(A) receptor clusters as well as presynaptic glutamate decarboxylase-positive terminals at the axon initial segment. By contrast, overexpression of neurofascin in hippocampal neurons increases gephyrin cluster size presumably via stimulation of fibroblast growth factor receptor 1 signaling pathways. 相似文献
82.
83.
84.
Khattar SK Bora RS Priyadarsiny P Gautam A Gupta D Tiwari A Nanda K Singh R Chugh A Bansal V Mookhtiar K Saini KS 《Biotechnology letters》2006,28(21):1731-1739
The cDNAs encoding for three subtypes of adrenergic receptors, α1A-, α1B- and α1D-ARs, were cloned and expressed in HEK 293 cells. Expression of α1A- and α1B-AR subtypes in HEK 293 cells was stable even with increased passages but that of α1D-AR was not. Cellular localization studies using immunofluorescence and flow cytometry revealed that expression of α1A- and α1B-ARs was primarily localized on the cell membrane whereas expression of α1D-AR was␣predominantly intracellular. Our studies clearly demonstrated that the culturing of the recombinant cell lines expressing α1D-AR in charcoal/dextran treated fetal bovine serum (FBS) resulted in targeting of α1D-AR to the cell membrane and thus, significantly improving its stability and availability for ligand binding studies.Sunil M. Khattar, Roop Singh Bora and Priyanka Priyadarsiny contributed equally to this work. 相似文献
85.
Monophyly of the order Rodentia inferred from mitochondrial DNA sequences of the genes for 12S rRNA, 16S rRNA, and tRNA-valine 总被引:1,自引:2,他引:1
A recent analysis of amino acid sequence data (Graur et al.) suggested that
the mammalian order Rodentia is polyphyletic, in contrast to most
morphological data, which support rodent monophyly. At issue is whether the
hystricognath rodents, such as the guinea pig, represent an independent
evolutionary lineage within mammals, separate from the sciurognath rodents.
To resolve this problem, we sequenced a region (2,645 bp) of the
mitochondrial genome of the guinea pig containing the complete 12S
ribosomal RNA, 16S ribosomal RNA, and transfer RNA(VAL) genes for
comparison with the available sciurognath and other mammalian sequences.
Several methods of analysis and statistical tests of the data all show
strong support for rodent monophyly (91%-98% bootstrap probability, or BP).
Calibration with the mammalian fossil record suggests a Cretaceous date
(107 mya) for the divergence of sciurognaths and hystricognaths. An older
date (38 mya) for the controversial Mus- Rattus divergence also is
supported by these data. Our neighbor-joining analyses of all available
sequence data (25 genes) confirm that some individual genes support rodent
polyphyly but that tandem analysis of all data does not. We propose that
the conflicting results are due to several compounding factors. The unique
biochemical properties of some hystricognath metabolic proteins, largely
responsible for generating this controversy, may have a single explanation:
a cascade effect resulting from inactivation of the zinc-binding abilities
of insulin. After excluding six genes possibly affected by insulin
inactivation, analyses of all available sequence data (7,117 nucleotide
sites, 3,099 amino acid sites) resulted in strong support for rodent
monophyly (94% BP for DNA sequences, 90% for protein sequences), which
lends support to the insulin-cascade hypothesis.
相似文献
86.
87.
88.
Lin Zhang Kumar Narayanan Harpriya Chugh Takahiro Shiota Zhi-Jie Zheng Sumeet S Chugh 《PloS one》2015,10(3)
Background
A growing literature suggests underutilization of the primary prevention implantable cardioverter-defibrillator (ICD); thus, factors influencing utilization need to be understood. We performed a comprehensive assessment of patient characteristics and health insurance status among subjects eligible for primary prevention ICD in a tertiary care center.Methods
From among a group of patients who met criteria for primary prevention ICD based on left ventricular dysfunction (LVEF ≤ 35%), ICD recipients (n = 110) were compared to ICD non-recipients (n = 110) to identify determinants of ICD implantation. We evaluated demographics, clinical profile including Charlson Comorbidity Index [CCI, categorized as low (≤3) or high (>3)] and health insurance status.Results
ICD recipients were younger (62.1±15.0 vs. 68.0±18.2; P = 0.01), with more males (80% vs. 65.5%; P = 0.01), higher NYHA class (II/III: 75.5% vs. 40.2%; P<0.001) and more likely to have supplemental private health insurance (61.8% vs. 46.4%; P = 0.02). CCI was not significantly different between the two groups (low CCI 61.8% vs. 62.7%; P = 0.89). In multivariable analysis, factors independently associated with ICD implantation were male sex (OR, 2.77, [1.31-5.85]; P = 0.01), age<75 (OR, 2.68, [1.30-5.50]; P = 0.01), private insurance (OR, 2.17, [1.08-4.36], P = 0.03) and NYHA Class II/III (OR, 5.91, [2.91-12.01]; P<0.001). Documentation of discussion about primary prevention ICD was absent in the majority (57.2%) of non-recipients.Conclusion
In a contemporary urban tertiary care setting, age, sex and heart failure symptom class were associated with ICD utilization, with socioeconomic/insurance status also potentially playing a role. These findings have implications for optimizing appropriate utilization of the prophylactic ICD and warrant follow-up in larger, more diverse populations. 相似文献89.
Background
In the hydrolysis of lignocellulosic materials, thermostable enzymes decrease the amount of enzyme needed due to higher specific activity and elongate the hydrolysis time due to improved stability. For cost-efficient use of enzymes in large-scale industrial applications, high-level expression of enzymes in recombinant hosts is usually a prerequisite. The main aim of the present study was to compare the biochemical and hydrolytic properties of two thermostable recombinant glycosyl hydrolase families 10 and 11 (GH10 and GH11, respectively) xylanases with respect to their potential application in the hydrolysis of lignocellulosic substrates.Results
The xylanases from Nonomuraea flexuosa (Nf Xyn11A) and from Thermoascus aurantiacus (Ta Xyn10A) were purified by heat treatment and gel permeation chromatography. Ta Xyn10A exhibited higher hydrolytic efficiency than Nf Xyn11A toward birchwood glucuronoxylan, insoluble oat spelt arabinoxylan and hydrothermally pretreated wheat straw, and it produced more reducing sugars. Oligosaccharides from xylobiose to xylopentaose as well as higher degree of polymerization (DP) xylooligosaccharides (XOSs), but not xylose, were released during the initial hydrolysis of xylans by Nf Xyn11A, indicating its potential for the production of XOS. The mode of action of Nf Xyn11A and Ta Xyn10A on glucuronoxylan and arabinoxylan showed typical production patterns of endoxylanases belonging to GH11 and GH10, respectively.Conclusions
Because of its high catalytic activity and good thermostability, T. aurantiacus xylanase shows great potential for applications aimed at total hydrolysis of lignocellulosic materials for platform sugars, whereas N. flexuosa xylanase shows more significant potential for the production of XOSs. 相似文献90.