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91.
Sequence variation among 10 alleles of the alcohol dehydrogenase (Adh) gene
of the Hawaiian drosophilid D. mimica was analyzed with reference to the
evolutionary history of the Hawaiian subgroup as well as to levels and
patterns of polymorphism of the Adh gene in continental drosophilid
species. The Adh gene of D. mimica is less polymorphic than that of other
drosophilid species, and no replacement substitutions were found.
Statistical analyses of the Adh alleles suggested the action of balancing
selection and revealed significant linkage disequilibrium among three of
the variable sites. The effective population size was estimated to be only
slightly smaller than that of continental species and, surprisingly, on the
same order of magnitude as the actual size.
相似文献
92.
Simplified colorimetric analysis of polymerase chain reactions: detection of HIV sequences in AIDS patients 总被引:4,自引:0,他引:4
D J Kemp M J Churchill D B Smith B A Biggs S J Foote M G Peterson N Samaras N J Deacon R Doherty 《Gene》1990,94(2):223-228
We have previously described a colorimetric test, designated an amplified DNA assay (ADA), for specific segments of DNA amplified by polymerase chain reactions (PCRs), suited to diagnostic applications. This relied on binding the amplified DNA via a sequence in one oligodeoxyribonucleotide (oligo) to the DNA-binding protein GCN4 coated on the wells of a microtiter dish. Avidin-peroxidase was then bound to biotin at the 5' end of the other oligo and detected colorimetrically. Two successive PCRs with nested oligos were utilized. We describe here several modifications that greatly simplify the ADA. First, we bind the DNA to a glutathione S-transferase-GCN4 fused polypeptide (GST-GCN4) and avidin-peroxidase simultaneously, rather than successively. Second, we carry out the two successive PCRs in the one reaction mixture, using the thermal stabilities of oligos of differing lengths to separate the two reactions. Third, PCRs can be performed in the wells of a microtiter dish and the amplified DNA captured and detected via GST-GCN4 immobilized on beads attached to the lid of the microtiter dish. Hence it is only necessary to pipette the DNA sample once, and up to 96 samples can then be handled simultaneously. 相似文献
93.
94.
Cristina Tena-Tomás Iara de Messias-Reason Le H Song Jürgen Tomiuk Peter G Kemsner Jürgen FJ Kun 《BMC genetics》2008,9(1):1-6
Background
Glutathione S-transferases (GSTs) is a genetic factor for many diseases and exhibits great diversities among various populations. We assessed association of the genotypes of Glutathione S-transferases Omega-1 (GSTO1) A140D with ethnicity in China.Results
Peripheral blood samples were obtained from 1314 individuals from 14 ethnic groups. Polymorphisms of GSTO1 A140D were measured using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Logistic regression was employed to adjustment for regional factor. The frequency of GSTO1 140A allele was 15.49% in the total 14 ethnic populations. Compared to Han ethnic group, two ethnic populations were more likely to have AA or CA genotype [odds ratio (OR): 1.77, 95% confidence interval (95% CI): 1.05–2.98 for Uygur and OR: 1.78, 95% CI: 1.18–2.69 for Hui]. However, there were no statistically significant differences across 14 ethnic groups when region factor was adjusted. In Han ethnicity, region was significantly associated with AA or CA genotype. Han individuals who resided in North-west of China were more likely to have these genotypes than those in South of China (OR: 1.63, 95% CI: 1.21–2.20).Conclusion
The prevalence of the GSTO1 140A varied significantly among different regional populations in China, which showed that geography played a more important role in the population differentiation for this allele than the ethnicity/race. 相似文献95.
K Samaras T V Nguyen A B Jenkins J A Eisman G M Howard P J Kelly L V Campbell 《Twin research》1999,2(3):218-225
Obesity, insulin resistance and disturbed glucose metabolism cluster within the Insulin Resistance Syndrome (IRS). Whether this reflects shared genetic or environmental factors detectable in 'normal' populations (not selected for IRS features) is unknown. This study estimated (i) genetic influences on IRS traits and (ii) shared and specific genetic and environmental factors on the relationships between these traits in healthy female twins. Fasting insulin, glucose, total and central fat were measured in 59 monozygotic (MZ) and 51 dizygotic (DZ) female twin pairs aged (+/- SD) 52 +/- 13 years. Body fat was measured by dual-energy X-ray absorptiometry, insulin resistance and secretion by a modified homeostasis model assessment. Using intraclass correlation coefficients and univariate model-fitting analyses, genetic influences were found in total fat, central fat, insulin resistance, fasting glucose and insulin secretion, with genetic factors explaining 64, 57, 59, 75 and 68% of their variance, respectively, using the latter technique. In matched analysis intra-pair differences in total and central fat related to intra-pair differences in insulin resistance (r2 = 0.19, P < 0.001). Multivariate model-fitting showed a close genetic relationship between total and central fat (r = 0.88). The genetic correlation between IR and central fat (0.41) was significantly greater than that for total fat (0.24), suggesting that central fat is not only a predictor of, but shares considerable genetic influence with, insulin resistance. In Cholesky analysis, these genetic influences were separate from those shared between central and total fat. In conclusion, both shared and specific genetic factors regulate components of the IRS in healthy females. However, there were discrete genetic influences on beta-cell insulin secretion, not shared with other IRS components, suggesting that a separate genetic propensity exists for Type 2 diabetes. These findings suggest we may understand the genetic and environmental influences on IRS from the study of the normal population. 相似文献
96.
Dendrinou-Samara C Papadopoulos AN Malamatari DA Tarushi A Raptopoulou CP Terzis A Samaras E Kessissoglou DP 《Journal of inorganic biochemistry》2005,99(3):864-875
Interaction of manganese with salicylhydroxamic ligands (shi) in methanol, in the presence of pyridine, leads to the formation of a series of 15-membered metallacrown (MC) Mn(II)(L)2[15-MCMn(III)N(shi)-5](py)6 or 7, (L=formato, benzoate or alkanoato ligand, py=pyridine). In the absence of pyridine, the Mn(II)(L)2[12-MCMn(III)N(shi)-4](MeOH)6 metallacrown was isolated and structurally characterized. The crystal structure of {[Mn(II)(HCOO)2][(15-MCMn(III)N(shi)-5)(py)7]}.py.1.9CH3OH.H2O (1) contains a neutral 15-membered metallacrown ring consisting of five Mn(III) and five shi(-3) ligands. The 15-membered metallacrown ring is formed by the succession of five structural moieties of the type [Mn(III)-N-O]. The diverse in the configuration (planar or propeller) for the ring Mn(III) ions gives the metallacrown core a bending structure. The crystal structure of {[Mn(II)(C6H5COO)2][(12-MCMn(III)N(shi)-4)(CH3OH)6]}.2CH3OH (2) contains a neutral 12-membered metallacrown ring consisting of four Mn(III) and four shi(-3) ligands. The 12-membered metallacrown ring is formed by the same way of succession of four structural moieties of the type [Mn(III)-N-O], while the presence of a planar only configuration of shi ligands around ring Mn(III) ions gives to the metallacrown core a planar structure. The encapsulated Mn(II) is six and seven-coordinate for (1) and (2), respectively, and is bound to the hydroximate oxygen of the metallacrown core and two oxygen atoms from the carboxylate ligands. Antibacterial screening data showed that, among all the compounds tested, manganese metallacrowns are more active compared to the simple manganese herbicide or carboxylate complexes, with increased efficiency for [15-MCMn(III)N(shi)-5] compared to the analogous [12-MCMn(III)N(shi)-4]. 相似文献
97.
98.
The islet beta cell-enriched RIPE3b1/Maf transcription factor regulates pdx-1 expression 总被引:3,自引:0,他引:3
Samaras SE Zhao L Means A Henderson E Matsuoka TA Stein R 《The Journal of biological chemistry》2003,278(14):12263-12270
99.
Gregory J. Zelinsky Hossein Adeli Yifan Peng Dimitris Samaras 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2013,368(1628)
We introduce a model of eye movements during categorical search, the task of finding and recognizing categorically defined targets. It extends a previous model of eye movements during search (target acquisition model, TAM) by using distances from an support vector machine classification boundary to create probability maps indicating pixel-by-pixel evidence for the target category in search images. Other additions include functionality enabling target-absent searches, and a fixation-based blurring of the search images now based on a mapping between visual and collicular space. We tested this model on images from a previously conducted variable set-size (6/13/20) present/absent search experiment where participants searched for categorically defined teddy bear targets among random category distractors. The model not only captured target-present/absent set-size effects, but also accurately predicted for all conditions the numbers of fixations made prior to search judgements. It also predicted the percentages of first eye movements during search landing on targets, a conservative measure of search guidance. Effects of set size on false negative and false positive errors were also captured, but error rates in general were overestimated. We conclude that visual features discriminating a target category from non-targets can be learned and used to guide eye movements during categorical search. 相似文献
100.
Samaras V Piperi C Korkolopoulou P Zisakis A Levidou G Themistocleous MS Boviatsis EI Sakas DE Lea RW Kalofoutis A Patsouris E 《Molecular and cellular biochemistry》2007,304(1-2):343-351
Glioblastoma, (grade IV astrocytoma), is characterized by rapid growth and resistance to treatment. Identification of markers
of aggressiveness in this tumor could represent new therapeutic targets. Interleukins (IL)-6 and IL-10 may be considered as
possible candidates, regulating cell growth, resistance to chemotherapy and angiogenesis. ELISPOT method provides a useful
tool for the determination of the exact cell number of peripheral lymphocytes secreting a specific cytokine. IL-6 and IL-10
secretion levels were determined using ELISPOT methodology in peripheral blood mononuclear cells of 18 patients with astrocytic
neoplasms (3 grade II and 15 grade IV), in parallel with 18 healthy controls. Additionally, immunohistochemical expression
of these two cytokines was performed in paraffin-embedded neoplastic tissue in 12 of these patients. The secretion of IL-6
from peripheral monocytes was significantly higher in glioma patients compared to controls (P = 0.0003). In addition, IL-10 secretion from peripheral mononuclear and tumor cells of glioma patients was also higher as
compared to healthy controls (P = 0.0002). Based on immunohistochemical staining, IL-6 expression was localized in tumor cells and macrophages as well as
in areas of large ischemic necrosis, while the major source of IL-10 expression in glioblastomas was the microglia/macrophage
cells. It is suggested that IL-10 contributes to the progression of astrocytomas by suppressing the patient’s immune response,
whereas IL-6 provides an additional growth advantage. This study demonstrates for the first time the usefulness of ELISPOT
in estimating the secretion of IL-6 and IL-10 from peripheral blood and the correlation of their expression in neoplastic
cells.
Christina Piperi and Penelope Korkolopoulou have equally contributed to this work. 相似文献