全文获取类型
收费全文 | 129篇 |
免费 | 10篇 |
出版年
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2012年 | 5篇 |
2011年 | 4篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 1篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 10篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1959年 | 5篇 |
1958年 | 5篇 |
1957年 | 4篇 |
1956年 | 4篇 |
1955年 | 3篇 |
1954年 | 6篇 |
1953年 | 2篇 |
1952年 | 4篇 |
1951年 | 3篇 |
1950年 | 4篇 |
1949年 | 4篇 |
1948年 | 1篇 |
排序方式: 共有139条查询结果,搜索用时 31 毫秒
81.
ABSTRACT: BACKGROUND: Solution-based targeted genomic enrichment (TGE) protocols permit selective sequencing of genomic regions of interest on a massively parallel scale. These protocols could be improved by: 1) modifying or eliminating time consuming steps; 2) increasing yield to reduce input DNA and excessive PCR cycling; and 3) enhancing reproducible. RESULTS: We developed a solution-based TGE method for downstream Illumina sequencing in a non-automated workflow, adding standard Illumina barcode indexes during the post-hybridization amplification to allow for sample pooling prior to sequencing. The method utilizes Agilent SureSelect baits, primers and hybridization reagents for the capture, off-the-shelf reagents for the library preparation steps, and adaptor oligonucleotides for Illumina paired-end sequencing purchased directly from an oligonucleotide manufacturing company. CONCLUSIONS: This solution-based TGE method for Illumina sequencing is optimized for small- or medium-sized laboratories and addresses the weaknesses of standard protocols by reducing the amount of input DNA required, increasing capture yield, optimizing efficiency, and improving reproducibility. 相似文献
82.
83.
84.
85.
86.
Carbohydrate recognition by proteins is a key event in many biological
processes. Concanavalin A is known to specifically recognize the
pentasaccharide core (beta-GlcNAc-(1-->2)-alpha- Man-(1-->3)-[beta-
GlcNAc-(1-->2)-alpha-Man-(1-->6)]-Man) of N-linked oligosaccharides
with a Ka of 1.41 x 10(6 )M-1. We have determined the structure of
concanavalin A bound to beta-GlcNAc-(1-->2)-alpha-Man-(1-->3)-[beta-
GlcNAc-(1-->2)-alpha-Man- (1-->6)]-Man to 2.7A. In six of eight
subunits there is clear density for all five sugar residues and a well
ordered binding site. The pentasaccharide adopts the same conformation in
all eight subunits. The binding site is a continuous extended cleft on the
surface of the protein. Van der Waals interactions and hydrogen bonds
anchor the carbohydrate to the protein. Both GlcNAc residues contact the
protein. The GlcNAc on the 1-->6 arm of the pentasaccharide makes
particularly extensive contacts and including two hydrogen bonds. The
binding site of the 1-->3 arm GlcNAc is much less extensive.
Oligosaccharide recognition by Con A occurs through specific protein
carbohydrate interactions and does not require recruitment of adventitious
water molecules. The beta-GlcNAc-(1-->2)-Man glycosidic linkage PSI
torsion angle on the 1-->6 arm is rotated by over 50 degrees from that
observed in solution. This rotation is coupled to disruption of
interactions at the monosaccharide site. We suggest destabilization of the
monosaccharide site and the conformational strain reduces the free energy
liberated by additional interactions at the 1-->6 arm GlcNAc site.
相似文献
87.
van Hoek AH; van Alen TA; Sprakel VS; Hackstein JH; Vogels GD 《Molecular biology and evolution》1998,15(9):1195-1206
The 18S and 5.8S rDNA genes and the internal transcribed spacers ITS-1 and
ITS-2 of ciliates living in the hindgut of frogs, millipedes, and
cockroaches were analyzed in order to study the evolution of intestinal
protists. All ciliates studied here belong to the genus Nycrotherus.
Phylogenetic analysis revealed that these ciliates from a monophyletic
group that includes the distantly related anaerobic free-living
heterotrichous ciliates Metopus palaeformis and Metopus contortus. The
intestinal ciliates from the different vertebrate and invertebrate hosts
are clearly divergent at the level of their rDNA repeats. This argues for
the antiquity of the associations and a predominantly vertical
transmission. This mode of transmission seems to be controlled primarily by
the behavior of the host. The different degrees of divergence between
ciliates living in different strains of one and the same cockroach species
most likely reflect the different geographical origins of the hosts. In
addition, host switches must have occurred during the evolution of
cockroaches, since identical ciliates were found only in distantly related
hosts. These phenomena prevent the reconstruction of potential cospeciation
events.
相似文献
88.
Sandra Stefanovic‐Barrett Anna S Dickson Stephen P Burr James C Williamson Ian T Lobb Dick JH van den Boomen Paul J Lehner James A Nathan 《EMBO reports》2018,19(5)
Misfolded or damaged proteins are typically targeted for destruction by proteasome‐mediated degradation, but the mammalian ubiquitin machinery involved is incompletely understood. Here, using forward genetic screens in human cells, we find that the proteasome‐mediated degradation of the soluble misfolded reporter, mCherry‐CL1, involves two ER‐resident E3 ligases, MARCH6 and TRC8. mCherry‐CL1 degradation is routed via the ER membrane and dependent on the hydrophobicity of the substrate, with complete stabilisation only observed in double knockout MARCH6/TRC8 cells. To identify a more physiological correlate, we used quantitative mass spectrometry and found that TRC8 and MARCH6 depletion altered the turnover of the tail‐anchored protein heme oxygenase‐1 (HO‐1). These E3 ligases associate with the intramembrane cleaving signal peptide peptidase (SPP) and facilitate the degradation of HO‐1 following intramembrane proteolysis. Our results highlight how ER‐resident ligases may target the same substrates, but work independently of each other, to optimise the protein quality control of selected soluble and tail‐anchored proteins. 相似文献
89.
The purpose of this study was to investigate the association between physical fitness and mild cognitive impairment (MCI) in elderly Koreans. This was a cross-sectional study that involved 134 men and 299 women aged 65 to 88 years. Six senior fitness tests were used as independent variables: 30 s chair stand for lower body strength, arm curl for upper body strength, chair-sit-and-reach for lower body flexibility, back scratch for upper body flexibility, 8-ft up-and-go for agility/dynamic balance, and 2-min walk for aerobic endurance. Global cognitive function was assessed using the Korean version of the Mini-Mental State Examination (MMSE). Potential covariates such as age, education levels, blood lipids, and insulin resistance (IR) markers were also assessed. Compared to individuals without MMSE-based MCI, individuals with MMSE-based MCI had poor physical fitness based on the senior fitness test (SFT). There were significant positive trends observed for education level (p=0.001) and MMSE score (p<0.001) across incremental levels of physical fitness in this study population. Individuals with moderate (OR=0.341, p=0.006) and high (OR=0.271, p=0.007) physical fitness based on a composite score of the SFT measures were less likely to have MMSE-based MCI than individuals with low physical fitness (referent, OR=1). The strength of the association between moderate (OR=0.377, p=0.038) or high (OR=0.282, p=0.050) physical fitness and MMSE-based MCI was somewhat attenuated but remained statistically significant even after adjustment for the measured compounding factors. We found that poor physical fitness was independently associated with MMSE-based MCI in elderly Koreans. 相似文献
90.
ANDREAS KLEEBERG HENDRIK SCHUBERT MATTHIAS KOSCHORRECK BRIGITTE NIXDORF 《Freshwater Biology》2006,51(5):925-937
1. In extremely acid mining lakes, benthic filamentous green algae (Zygnemataceae, Chlorophyta) thrive as effective competitors for limited carbon (C). These algae could supply C for microbial‐mediated benthic alkalinity generation. However, biomass, productivity and impact of the acidobiontic filamentous green algae at pH ≤3 have not previously been determined. 2. Periphytic filamentous green algae was mapped by harvesting their biomass from 85 1 × 1 m quadrats in mining lake Grünewalder Lauch. Zygogonium ericetorum colonised water depths between 1.6 and 10.5 m covering 88% of total area. Biomass peaked at 5–6 m depth. Total Zygogonium biomass amounted to 72.2 t dry weight for the whole lake (0.94 km2), which corresponds to 16.1 t C and the accumulation of primary production from 2.2 years. 3. Growth of Zygogonium is moderately N, C and extremely P deficient, and seriously stressed by high rates of Fe deposition during summer. Consequently, net primary production (NPP) of Zygogonium, calculated from measured photosynthesis versus irradiance characteristics and calculated underwater irradiance (0.13 g C m?2 year?1) and in situ oxygen measurements (7.8 g C m?2 year?1), corresponds to only 0.3% and 18.1% of pelagic NPP. 4. Neither pelagic nor benthic Zygogonium primary production can supply enough C for efficient acidity removal. However, at rates of benthic NPP in summer of 21.4 mg C m?2 day?1, Zygogonium contributed 26% of the C equivalents to remove acidity associated with ferric iron, contributing at least seasonally to efficient alkalinity generation. 相似文献