全文获取类型
收费全文 | 67篇 |
免费 | 8篇 |
专业分类
75篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 6篇 |
2011年 | 1篇 |
2010年 | 7篇 |
2009年 | 3篇 |
2007年 | 5篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1997年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1971年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有75条查询结果,搜索用时 15 毫秒
1.
Rafael L. X. Consani Mariana R. Carmignani Marcelo F. Mesquita Lourenço Correr‐Sobrinho Ricardo D. Guiraldo 《Gerodontology》2010,27(3):236-242
doi:10.1111/j.1741‐2358.2009.00333.x Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin Objective: The purpose of this study was to verify the effect of microwave treatment on the shear bond strength of commercial types of teeth to acrylic resin, when the glossy ridge laps were unmodified (groups 1 and 5), bur abraded (groups 2 and 6), bur grooved (groups 3 and 7) or etched by monomer (groups 4 and 8). Background: Controversial findings have shown that mechanical or chemical changes in ridge‐lap surface of the tooth increase or decrease the bond strength between tooth and acrylic resin, and the microwave disinfection may cause different changes on this bond strength. Materials and methods: Eighty specimens (n = 10) were made with the acrylic resin bonded to tooth glossy ridge lap, polymerised in water at 74°C for 9 h, and deflasked after flask cooling. Specimens of the groups 5, 6, 7 and 8 were individually immersed in 150 ml of water and submitted to microwave treatment in an oven at 650 W for 3 min. Control specimens (groups 1, 2, 3 and 4) were not microwave treated. Shear bond strength test was performed in an Instron machine with a cross‐speed of 1 mm/min. Collected data were submitted to anova and Tukey’s test (α = 0.05). Results: Microwave treatment decreased the shear bond strength values of the tooth/resin bond. In the microwaved and non‐microwaved procedures, mechanical retention improved the shear bond strength when compared with the control and monomer treatments. Conclusion: Shear bond strength of the tooth/resin bond was influenced by the microwave treatment and different commercial teeth association, and was lower for the Biotone tooth. 相似文献
2.
Mellissa S. Sobrinho Marcelo Tabarelli Isabel C. Machado Júlia C. Sfair Emilio M. Bruna Ariadna V. Lopes 《Biotropica》2016,48(5):586-597
Caatinga vegetation continues to be converted into mosaics of secondary forest stands, but the affect of this process on biodiversity has not yet been examined. We used 35 regenerating and old‐growth stands of Caatinga to examine the recovery of plant assemblages subsequent to slash‐and‐burn agriculture and cattle ranching/pasture in northeastern Brazil. Plant assemblages were contrasted in terms of community structure (stem density/basal area/species richness/diversity), functional (leaf habit/reproductive traits) and taxonomic composition. Soil attributes were also examined to infer potential drivers for cross‐habitat differences. As expected, plant assemblages clearly differed across a large set of community‐level attributes, including all trait categories relative to leaf habit and reproduction (pollination syndrome/floral color, size, type). Overall, old‐growth forest stands supported distinct and more diverse assemblages at the plot and habitat level; e.g., long‐lived tree species were almost exclusively found in old‐growth forest stands. For most attributes, plant assemblages subsequent to pasture exhibited intermediate values between those exhibited by old‐growth forest and those of agriculture‐related stands. Surprisingly, soils exhibited similar fertility‐related scores across habitats. Our results indicate that: (1) sprouting/resprouting represents an important mechanism of forest regeneration; (2) assemblage‐level attributes suggest recovery at distinct rates; (3) forest regeneration implies community‐level changes in both vegetative and reproductive functional attributes, including directional changes; (4) Caatinga is not able to completely recover in a period of 15‐yr following land abandonment; and (5) historical land use affects recovery rates and successional pathways/taxonomic trajectories. Seasonally dry tropical forests may intrinsically cover a wide range of patterns relative to successional model, recovery rates and successional pathways. 相似文献
3.
Julie Massayo Maeda Oda Karen Braj?o de Oliveira Roberta Losi Guembarovski Kalil William Alves de Lima Ana Cristina da Silva do Amaral Herrera Alda Losi Guembarovski Walter Jorge Sobrinho Daniela Rudgeri Derossi Maria Angelica Ehara Watanabe 《Molecular biology reports》2012,39(12):10131-10137
The role of chemokines and the growth factors has been extensively analyzed both in cancer risk and tumor progression. The transforming growth factor beta (TGF-β) and chemokine (C-X-C motif) receptor 4 (CXCR4) genes are implicated in several diseases, including breast cancer. Genomic DNA was obtained from 21 samples of peripheral blood or from normal tissue, previously fixed in formalin and embedded in paraffin for TGF-β T869C polymorphism analyses. Total cellular RNA was extracted from the same 21 patients, but from fresh tissue (tumor and adjacent healthy from the same breast) for expression analysis by Real Time PCR. No significant differences were observed in genotype distribution according to clinicopathological characteristics. Transforming growth factor beta (TGF-β) mRNA expression was assessed according to T869C polymorphism and CC patients presented a higher TGF-β expression but not significant when compared to other genotypes (p?=?0.064). A positive correlation was observed in relative mRNA expressions of CXCR4 and TGF-β (p?=?0.020). It is known that overexpression of TGF-β by both tumor and stromal tissue can facilitate the development of metastases, mainly by TGF-β stimulated angiogenesis and increased tumor cell motility. Our findings suggested a role of these genes as progression markers for breast carcinoma. 相似文献
4.
Recovery of Cryptosporidium oocysts and Giardia cysts from source water concentrates using immunomagnetic separation 总被引:3,自引:0,他引:3
Immunomagnetic separation (IMS) procedures for the simultaneous isolation of Cryptosporidium oocysts and Giardia cysts have recently become available. We validated Dynal's GC-Combo IMS kit using source water at three turbidity levels (5000, 500 and 50 nephelometric turbidity units [ntu]) obtained from different geographical locations and spiked with approximately 9--11 (oo)cysts per ml. Mean recoveries of Cryptosporidium oocysts and Giardia cysts in deionized water were 62% and 69%, respectively. In turbid water matrices, mean recoveries of Cryptosporidium oocysts were between 55.9% and 83.1% while mean recoveries of cysts were between 61.1% and 89.6%. Marginally higher recoveries of the heat inactivated (oo)cysts were observed (119.4% Cryptosporidium oocysts and 90.9% Giardia cysts) in deionized water when compared with recoveries of viable (oo)cysts (69.7% Cryptosporidium oocysts and 79% Giardia cysts). Age of (oo)cysts on recoveries using the GC-Combo IMS kit demonstrated no effects up to 20 months old. Recovery of Giardia cysts was consistent for isolates aged up to 8 months (81.4%), however, a significant reduction in recoveries was noted at 20 months age. Recoveries of low levels (5 and 10 (oo)cysts) of Cryptosporidium oocysts and Giardia cysts in deionized water using IMS ranged from 51.3% to 78% and from 47.6% to 90.0%, respectively. Results of this study indicate that Dynal's GC-Combo IMS kit is an efficient technique to separate Cryptosporidium/Giardia from turbid matrices and yields consistent, reproducible recoveries. The use of fresh (recently voided and purified) (oo)cysts, aged (oo)cysts, viable and heat-inactivated (oo)cysts indicated that these parameters do not influence IMS performance. 相似文献
5.
A comparative description of mitochondrial DNA differentiation in selected avian and other vertebrate genera 总被引:13,自引:1,他引:13
Levels of mitochondrial DNA (mtDNA) sequence divergence between species
within each of several avian (Anas, Aythya, Dendroica, Melospiza, and
Zonotrichia) and nonavian (Lepomis and Hyla) vertebrate genera were
compared. An analysis of digestion profiles generated by 13-18 restriction
endonucleases indicates little overlap in magnitude of mtDNA divergence for
the avian versus nonavian taxa examined. In 55 interspecific comparisons
among the avian congeners, the fraction of identical fragment lengths (F)
ranged from 0.26 to 0.96 (F = 0.46), and, given certain assumptions, these
translate into estimates of nucleotide sequence divergence (p) ranging from
0.007 to 0.088; in 46 comparisons among the fish and amphibian congeners, F
values ranged from 0.00 to 0.36 (F = 0.09), yielding estimates of P greater
than 0.070. The small mtDNA distances among avian congeners are associated
with protein-electrophoretic distances (D values) less than approximately
0.2, while the mtDNA distances among assayed fish and amphibian congeners
are associated with D values usually greater than 0.4. Since the
conservative pattern of protein differentiation previously reported for
many avian versus nonavian taxa now appears to be paralleled by a
conservative pattern of mtDNA divergence, it seems increasingly likely that
many avian species have shared more recent common ancestors than have their
nonavian taxonomic counterparts. However, estimates of avian divergence
times derived from mtDNA- and protein-calibrated clocks cannot readily be
reconciled with some published dates based on limited fossil remains. If
the earlier paleontological interpretations are valid, then protein and
mtDNA evolution must be somewhat decelerated in birds. The empirical and
conceptual issues raised by these findings are highly analogous to those in
the long-standing debate about rates of molecular evolution and times of
separation of ancestral hominids from African apes.
相似文献
6.
In this study, the composition of ant communities was compared in four adjacent phytophysiognomies in Morro dos Conventos
Restinga, Brazil. We tested our hypothesis that the ant community composition differs between habitats across a gradient from
sea to inland continent. Ant species were sampled with pitfall traps. Overall, 71 ant species were collected. Ant species
composition differed between phytophysiognomies. Our results suggest that environments were more similar in the adjacent than
in the more distant phytophysiognomies, a pattern similar to the vegetation zonation and gradient sea–inland Restinga. Thirteen
species determined more than 50% of the dissimilarity between phytophysiognomies. Solenopsis saevissima was the species that contributed more to ant species composition distinction between phytophysiognomies, followed by Pheidole and Camponotus species. The type of vegetation is one of the main factors affecting the composition of ant communities in Restinga. The
role of plants is linked to the availability of resources and conditions and they may determine ant assemblage composition
and different interactions occurring in Restinga. 相似文献
7.
Lucas N. Paolucci Ricardo R. C. Solar Tathiana G. Sobrinho Carlos F. Sperber José H. Schoereder 《Biodiversity and Conservation》2012,21(12):3095-3105
Remnant isolation following fragmentation is considered to be one of the main drivers of ecological decline in modified landscapes. Thereby, connecting remnants using ecological corridors has been increasingly suggested as being important for conservation. Our objectives were to test isolation effects on extinction, colonization and turnover rates of a litter-dwelling ant assemblage, and to evaluate effectiveness of ecological corridors to mitigate habitat fragmentation consequences. We used a mesocosm manipulative design, with three different isolation treatments: far, near and near connected by a corridor, sampled fortnightly for 60?days. Fragmentation caused an ongoing decrease in ant species richness, probably due to a negative balance between extinction and colonization. Extinction was steady with time, while colonization decreased over the same period. This outcome highlights the key role that colonization plays in the persistence of populations of litter-dwelling ants. Turnover rates increased with time in the treatment with a corridor, but remained steady in the other treatments. We conclude that corridors are important for not only immigration to remnants, but also emigration, acting as a two way traffic route. Thus, it may be an important “leakage” point for threatened species, with implications for their conservation status. 相似文献
8.
Keller Ricardo Ferreira Sobrinho Ana Carolina Monteiro Santini Carlos Leonardo Sacomani Marques Maicon Gonçalves Gabriel Eduardo de Moura Neto Luciane Aparecida Pascucci Sande de Souza 《Somatosensory & motor research》2013,30(3-4):199-203
AbstractBackground: Unilateral spatial neglect (USN) is the prevalent feature in patients with right-sided stroke. It is diagnosed through the behavior inattention test (BIT) and has a negative impact on patients affecting both their functional capacity and quality of life.Objective: Here, we aimed to evaluate the impact of USN on the quality of life of patients in the chronic phase of stroke.Methods: This is a cross-sectional study with stroke patients with USN. After confirming the presence of stroke through neuroimaging examinations and of USN through the BIT, patients’ quality of life was evaluated by using the EUROQOL scale. Spearman’s correlation was used to validate the correlation between patients’ USN and quality of life, with a p?<?.05 representing significant results.Results: Eighteen individuals were included. When correlating the value of each domain of the EUROQOL scale with the results of the BIT, we observed a negative correlation between mobility (r?=?–0.97; p?=?.000), self-care (r?=?–0.82; p?=?.013), usual activities (r?=?–0.87; p?=?.005); pain or discomfort (r?=?–0.88; p?=?.004), anxiety or depression (r?=?–0.97; p?=?.000), and EUROQOL total score (r?=?–0.97, p?=?.000).Conclusion: After a correlation between the overall EUROQOL and BIT scores, we suggest that the higher the USN degree is in stroke patients, the worse their perceived quality of life tends to be. 相似文献
9.
10.
We studied different genetic models and evaluation systems to select against a genetic disease with additive, recessive or polygenic inheritance in genetic conservation schemes. When using optimum contribution selection with a restriction on the rate of inbreeding (ΔF) to select against a disease allele, selection directly on DNA-genotypes is, as expected, the most efficient strategy. Selection for BLUP or segregation analysis breeding value estimates both need 1–2 generations more to halve the frequency of the disease allele, while these methods do not require knowledge of the disease mutation at the DNA level. BLUP and segregation analysis methods were equally efficient when selecting against a disease with single gene or complex polygene inheritance, i.e. knowledge about the mode of inheritance of the disease was not needed for efficient selection against the disease. Smaller schemes or schemes with a more stringent restriction on ΔF needed more generations to halve the frequency of the disease alleles or the fraction of diseased animals. Optimum contribution selection maintained ΔF at its predefined level, even when selection of females was at random. It is argued that in the investigated small conservation schemes with selection against a genetic defect, control of ΔF is very important. 相似文献