全文获取类型
收费全文 | 71篇 |
免费 | 5篇 |
出版年
2021年 | 2篇 |
2020年 | 1篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 9篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 5篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1998年 | 5篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有76条查询结果,搜索用时 15 毫秒
1.
A new siderophore was isolated and purified from the spent growth medium of the fungus Helminthosporium carbonum by solvent extraction and reverse phase high pressure liquid chromatography. This new molecule has been assigned the name Canadaphore. Canadaphore was detected in culture filtrates after 15 days of growth and production was maximal after growth of H. carbonum to maximal stationary phase in modified Fries basal medium. Production of Canadaphore was completely suppressed when the organism was grown in medium supplemented with iron. Mass spectral analysis yielded a molecular mass of 680 Daltons for the iron-Canadaphore complex and 627 Daltons for the iron-free molecule. Spectroscopic analysis indicates that Canadaphore is a siderophore of the hydroxamate type. 相似文献
2.
The tryptophan hydroxylase of Chromobacterium violaceum 总被引:2,自引:0,他引:2
3.
Litman GW; Rast JP; Shamblott MJ; Haire RN; Hulst M; Roess W; Litman RT; Hinds- Frey KR; Zilch A; Amemiya CT 《Molecular biology and evolution》1993,10(1):60-72
Immunoglobulins are encoded by a large multigene system that undergoes
somatic rearrangement and additional genetic change during the development
of immunoglobulin-producing cells. Inducible antibody and antibody-like
responses are found in all vertebrates. However, immunoglobulin possessing
disulfide-bonded heavy and light chains and domain-type organization has
been described only in representatives of the jawed vertebrates. High
degrees of nucleotide and predicted amino acid sequence identity are
evident when the segmental elements that constitute the immunoglobulin gene
loci in phylogenetically divergent vertebrates are compared. However, the
organization of gene loci and the manner in which the independent elements
recombine (and diversify) vary markedly among different taxa. One striking
pattern of gene organization is the "cluster type" that appears to be
restricted to the chondrichthyes (cartilaginous fishes) and limits
segmental rearrangement to closely linked elements. This type of gene
organization is associated with both heavy- and light-chain gene loci. In
some cases, the clusters are "joined" or "partially joined" in the germ
line, in effect predetermining or partially predetermining, respectively,
the encoded specificities (the assumption being that these are expressed)
of the individual loci. By relating the sequences of transcribed gene
products to their respective germ-line genes, it is evident that, in some
cases, joined-type genes are expressed. This raises a question about the
existence and/or nature of allelic exclusion in these species. The
extensive variation in gene organization found throughout the vertebrate
species may relate directly to the role of intersegmental
(V<==>D<==>J) distances in the commitment of the individual
antibody-producing cell to a particular genetic specificity. Thus, the
evolution of this locus, perhaps more so than that of others, may reflect
the interrelationships between genetic organization and function.
相似文献
4.
The purification of polynucleotide phosphorylase from Micrococcus luteus by chromatography on phosphocellulose columns is described. This procedure offers several advantages over previous procedures. 相似文献
5.
Two silicone coatings have been evaluated for barnacle adhesion. One coating is an unfilled hydrosilation cured polydimethylsiloxane (PDMS) network, while the other is a room temperature vulcanized (RTV), filled, ethoxysiloxane cured PDMS elastomer, RTV11?. The adhesion strength of one species of barnacle, Balanus eburneus, to the hydrosilation coatings is in the range of 0.37–0.60 kg cm‐2 while the corresponding range for RTV11 is 0.64–0.90 kg cm‐2. The easier release of B. eburneus from the hydrosilation cured network compared to RTV11 is discussed in relationship to differences in bulk and surface properties. Preliminary results suggest bulk modulus may be the most important parameter in determining barnacle adhesion strength. In light or mechanical property analysis, a re‐evaluation of surface properties and chemical stability is presented. 相似文献
6.
Walter Royal III Mariana Cherner Tricia H. Burdo Anya Umlauf Scott L. Letendre Jibreel Jumare Alash’le Abimiku Peter Alabi Nura Alkali Sunday Bwala Kanayo Okwuasaba Lindsay M. Eyzaguirre Christopher Akolo Ming Guo Kenneth C. Williams William A. Blattner 《PloS one》2016,11(2)
The potential role of gender in the occurrence of HIV-related neurocognitive impairment (NCI) and associations with markers of HIV-related immune activity has not been previously examined. In this study 149 antiretroviral-naïve seropositive subjects in Nigeria (SP, 92 women and 57 men) and 58 seronegative (SN, 38 women and 20 men) were administered neuropsychological testing that assessed 7 ability domains. From the neuropsychological test scores was calculated a global deficit score (GDS), a measure of overall NCI. Percentages of circulating monocytes and plasma HIV RNA, soluble CD163 and soluble CD14 levels were also assessed. HIV SP women were found to be younger, more educated and had higher CD4+ T cell counts and borderline higher viral load measures than SP men. On the neuropsychological testing, SP women were more impaired in speed of information processing and verbal fluency and had a higher mean GDS than SN women. Compared to SP men, SP women were also more impaired in speed of information processing and verbal fluency as well as on tests of learning and memory. Numbers of circulating monocytes and plasma sCD14 and sCD163 levels were significantly higher for all SP versus all SN individuals and were also higher for SP women and for SP men versus their SN counterparts. Among SP women, soluble CD14 levels were slightly higher than for SP men, and SP women had higher viral load measurements and were more likely to have detectable virus than SP men. Higher sCD14 levels among SP women correlated with more severe global impairment, and higher viral load measurements correlated with higher monocyte numbers and sCD14 and sCD14 levels, associations that were not observed for SP men. These studies suggest that the risk of developing NCI differ for HIV infected women and men in Nigeria and, for women, may be linked to effects from higher plasma levels of HIV driving activation of circulating monocytes. 相似文献
7.
Magda Budzowska Thomas GW Graham Alexandra Sobeck Shou Waga Johannes C Walter 《The EMBO journal》2015,34(14):1971-1985
DNA interstrand cross‐links (ICLs) are repaired in S phase by a complex, multistep mechanism involving translesion DNA polymerases. After replication forks collide with an ICL, the leading strand approaches to within one nucleotide of the ICL (“approach”), a nucleotide is inserted across from the unhooked lesion (“insertion”), and the leading strand is extended beyond the lesion (“extension”). How DNA polymerases bypass the ICL is incompletely understood. Here, we use repair of a site‐specific ICL in Xenopus egg extracts to study the mechanism of lesion bypass. Deep sequencing of ICL repair products showed that the approach and extension steps are largely error‐free. However, a short mutagenic tract is introduced in the vicinity of the lesion, with a maximum mutation frequency of ~1%. Our data further suggest that approach is performed by a replicative polymerase, while extension involves a complex of Rev1 and DNA polymerase ζ. Rev1–pol ζ recruitment requires the Fanconi anemia core complex but not FancI–FancD2. Our results begin to illuminate how lesion bypass is integrated with chromosomal DNA replication to limit ICL repair‐associated mutagenesis. 相似文献
8.
Nano FE Zhang N Cowley SC Klose KE Cheung KK Roberts MJ Ludu JS Letendre GW Meierovics AI Stephens G Elkins KL 《Journal of bacteriology》2004,186(19):6430-6436
Francisella tularensis is a gram-negative, facultative intracellular pathogen that causes the highly infectious zoonotic disease tularemia. We have discovered a ca. 30-kb pathogenicity island of F. tularensis (FPI) that includes four large open reading frames (ORFs) of 2.5 to 3.9 kb and 13 ORFs of 1.5 kb or smaller. Previously, two small genes located near the center of the FPI were shown to be needed for intramacrophage growth. In this work we show that two of the large ORFs, located toward the ends of the FPI, are needed for virulence. Although most genes in the FPI encode proteins with amino acid sequences that are highly conserved between high- and low-virulence strains, one of the FPI genes is present in highly virulent type A F. tularensis, absent in moderately virulent type B F. tularensis, and altered in F. tularensis subsp. novicida, which is highly virulent for mice but avirulent for humans. The G+C content of a 17.7-kb stretch of the FPI is 26.6%, which is 6.6% below the average G+C content of the F. tularensis genome. This extremely low G+C content suggests that the DNA was imported from a microbe with a very low G+C-containing chromosome. 相似文献
9.
Walter P Maksymowych Anthony S Russell Peter Chiu Alex Yan Niall Jones Tracey Clare Robert GW Lambert 《Arthritis research & therapy》2012,14(5):1-7
Introduction
Inflammation associated with synovial expression of TNFα is a recognised feature of osteoarthritis (OA), although no studies have yet reported beneficial effects of anti-TNFα therapy on clinical manifestations of inflammation in OA.Methods
We conducted an open-label evaluation of adalimumab over 12 weeks in 20 patients with OA of the knee and evidence of effusion clinically. Inclusion criteria included daily knee pain for the month preceding study enrolment and a summed pain score of 125 to 400 mm visual analogue scale on the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) pain subscale. The primary outcome was the Osteoarthritis Research Society International/Outcome Measures in Rheumatology Clinical Trials (OARSI/OMERACT) response criterion at week 12. Secondary outcomes included the WOMAC pain score 20% and 50% improvement, WOMAC stiffness and function scores, patient and physician global visual analogue scale, as well as target joint swelling.Results
Treatment was well tolerated and completed by 17 patients with withdrawals unrelated to lack of efficacy or adverse events. By intention to treat, an OARSI/OMERACT response was recorded in 14 (70%) patients. WOMAC pain 20% and 50% responses were recorded in 14 (70%) patients and eight (40%) patients, respectively. Significant improvement was observed in mean WOMAC pain, stiffness, function, physician and patient global, as well as target joint swelling at 12 weeks (P < 0.0001 for all). After treatment discontinuation, 16 patients were available for assessment at 22 weeks and OARSI/OMERACT response compared with baseline was still evident in 10 (50%) patients.Conclusion
Targeting TNFα may be of therapeutic benefit in OA and requires further evaluation in controlled trials.Trial registration
ClinicalTrials.gov: . NCT00686439相似文献10.
Ulrich Weber Susanne J Pedersen Mikkel ?stergaard Kaspar Rufibach Robert GW Lambert Walter P Maksymowych 《Arthritis research & therapy》2012,14(3):R124