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排序方式: 共有273条查询结果,搜索用时 250 毫秒
111.
Farjalla VF Marinho CC Faria BM Amado AM Esteves Fde A Bozelli RL Giroldo D 《Microbial ecology》2009,57(4):657-666
The main goal of this research was to evaluate whether the mixture of fresh labile dissolved organic matter (DOM) and accumulated
refractory DOM influences bacterial production, respiration, and growth efficiency (BGE) in aquatic ecosystems. Bacterial
batch cultures were set up using DOM leached from aquatic macrophytes as the fresh DOM pool and DOM accumulated from a tropical
humic lagoon. Two sets of experiments were performed and bacterial growth was followed in cultures composed of each carbon
substrate (first experiment) and by carbon substrates combined (second experiment), with and without the addition of nitrogen
and phosphorus. In both experiments, bacterial production, respiration, and BGE were always higher in cultures with N and
P additions, indicating a consistent inorganic nutrient limitation. Bacterial production, respiration, and BGE were higher
in cultures set up with leachate DOM than in cultures set up with humic DOM, indicating that the quality of the organic matter
pool influenced the bacterial growth. Bacterial production and respiration were higher in the mixture of substrates (second
experiment) than expected by bacterial production and respiration in single substrate cultures (first experiment). We suggest
that the differences in the concentration of some compounds between DOM sources, the co-metabolism on carbon compound decomposition,
and the higher diversity of molecules possibly support a greater bacterial diversity which might explain the higher bacterial
growth observed. Finally, our results indicate that the mixture of fresh labile and accumulated refractory DOM that naturally
occurs in aquatic ecosystems could accelerate the bacterial growth and bacterial DOM removal. 相似文献
112.
A novel hydrogel was obtained by reticulation of chitosan with dextrin enzymatically linked to vinyl acrylate (dextrin-VA), without cross-linking agents. The hydrogel had a solid-like behaviour with G′ (storage modulus) >> G″ (loss modulus). Glucose diffusion coefficients of 3.9 × 10−6 ± 1.3 × 10−6 cm2/s and 2.9 × 10−6 ± 0.5 × 10−6 cm2/s were obtained for different substitution degrees of the dextrin-VA (20% and 70% respectively). SEM observation revealed a porous structure, with pores ranging from 50 μm to 150 μm. 相似文献
113.
Monteiro FO de Koivisto MB Vicente WR de Amorim Carvalho R Whiteman CW Castro PH Maia CE 《Journal of medical primatology》2006,35(3):123-130
BACKGROUND: Gynecological and obstetrical ultrasonography has become an indispensable tool in the routine management, health evaluation and research on captive non-human primates. METHODS: Ultrasound was used to evaluate the uterus and estimate the gestation of owl monkeys. Twelve couples were selected, where five were primiparous and seven multiparous females from the National Primate Center reproductive colony, Ananindeua-PA, Brazil. The procedures were carried out using the GE Logiq 100 MP, equipped with a 7.5 MHz linear probe. RESULTS: The females showed a simple uterus, of elongated shape, regular outline and homogeneous echogenic texture. In the uterine measurements craniocaudal diameter, dorsoventral diameter and uterine volume (UV), significant differences were identified (P < 0.05) between ultrasound examinations of primiparous and multiparous females. The UV showed a positive correlation with the number of births. The gestational sac and the embryonic echo were visible between 28 and 38 days after mating. Between 48 and 68 days after mating, embryonic death was identified in all the gestations. CONCLUSIONS: The chemical (use of tranquilizers) and husbandry factors (capture stress) may be related to the prenatal death. The establishing methods of conditioning the female to the ultrasonographic exam may offer a solution to this problem. 相似文献
114.
Xavier Cornejo Scott A. Mori Reinaldo Aguilar Hannah Stevens Francine Douwes 《Brittonia》2012,64(1):76-101
A phytogeographic analysis of the distributions of 454 species of trees native to the Osa Peninsula in 22 families revealed
that 4.8% of the species are endemic to the Osa Peninsula and the adjacent mainland of Costa Rica. However, nearly one-fourth
of the species might be regionally endemic to Central-South Mesoamerica (Costa Rica, Nicaragua, and Panama). Our sample suggests
that 53.6% of the species occur in some part of Mesoamerica and sometimes range into northwestern South America, and that
44.5% of the species have wide distributions throughout tropical America. There is a strong affinity with the flora of northwestern
South America, with 46.2% of the species on the Osa also found there. In addition, 50.6% of the tree species on the Osa occur
on both the Atlantic and Pacific slopes of Central America or, if they reach South America, are sometimes found on both sides
of the Andes. Major contributions to the tree flora of the Osa have been made by species arriving in the Osa by 1) dispersal
from South and North America to islands in proto Central America before the formation of a dry-land connection between the
two continents, and 2) migration from South America and North America after the closure of the Panamanian isthmus was made.
This analysis demonstrates the importance of the Osa as a regional refuge for protecting species with distributions limited
to the Osa and parts of Panama, Costa Rica, or Nicaragua. The Osa is also important because it harbors the last expanse of
tropical wet forest on the Pacific slope of Central America large enough to ensure the survival of the Central American populations
of widely distributed plants and animals. 相似文献
115.
Correa-Costa M Semedo P Monteiro AP Silva RC Pereira RL Gonçalves GM Marques GD Cenedeze MA Faleiros AC Keller AC Shimizu MH Seguro AC Reis MA Pacheco-Silva A Câmara NO 《PloS one》2010,5(12):e14298
Background
The tubule-interstitial fibrosis is the hallmark of progressive renal disease and is strongly associated with inflammation of this compartment. Heme-oxygenase-1 (HO-1) is a cytoprotective molecule that has been shown to be beneficial in various models of renal injury. However, the role of HO-1 in reversing an established renal scar has not yet been addressed.Aim
We explored the ability of HO-1 to halt and reverse the establishment of fibrosis in an experimental model of chronic renal disease.Methods
Sprague-Dawley male rats were subjected to unilateral ureteral obstruction (UUO) and divided into two groups: non-treated and Hemin-treated. To study the prevention of fibrosis, animals were pre-treated with Hemin at days -2 and -1 prior to UUO. To investigate whether HO-1 could reverse established fibrosis, Hemin therapy was given at days 6 and 7 post-surgery. After 7 and/or 14 days, animals were sacrificed and blood, urine and kidney tissue samples were collected for analyses. Renal function was determined by assessing the serum creatinine, inulin clearance, proteinuria/creatininuria ratio and extent of albuminuria. Arterial blood pressure was measured and fibrosis was quantified by Picrosirius staining. Gene and protein expression of pro-inflammatory and pro-fibrotic molecules, as well as HO-1 were performed.Results
Pre-treatment with Hemin upregulated HO-1 expression and significantly reduced proteinuria, albuminuria, inflammation and pro-fibrotic protein and gene expressions in animals subjected to UUO. Interestingly, the delayed treatment with Hemin was also able to reduce renal dysfunction and to decrease the expression of pro-inflammatory molecules, all in association with significantly reduced levels of fibrosis-related molecules and collagen deposition. Finally, TGF-β protein production was significantly lower in Hemin-treated animals.Conclusion
Treatment with Hemin was able both to prevent the progression of fibrosis and to reverse an established renal scar. Modulation of inflammation appears to be the major mechanism behind HO-1 cytoprotection. 相似文献116.
Marina L. Kennerson Garth A. Nicholson Stephen G. Kaler Julian F.B. Mercer Roxana M. Llanos Reinaldo I. Takata Jonathan Baets Dirk Fischer Philip E. Taylor Toby A. Ferguson Peter De Jonghe Michael E. Shy 《American journal of human genetics》2010,86(3):343-352
Distal hereditary motor neuropathies comprise a clinically and genetically heterogeneous group of disorders. We recently mapped an X-linked form of this condition to chromosome Xq13.1-q21 in two large unrelated families. The region of genetic linkage included ATP7A, which encodes a copper-transporting P-type ATPase mutated in patients with Menkes disease, a severe infantile-onset neurodegenerative condition. We identified two unique ATP7A missense mutations (p.P1386S and p.T994I) in males with distal motor neuropathy in two families. These molecular alterations impact highly conserved amino acids in the carboxyl half of ATP7A and do not directly involve the copper transporter''s known critical functional domains. Studies of p.P1386S revealed normal ATP7A mRNA and protein levels, a defect in ATP7A trafficking, and partial rescue of a S. cerevisiae copper transport knockout. Although ATP7A mutations are typically associated with severe Menkes disease or its milder allelic variant, occipital horn syndrome, we demonstrate here that certain missense mutations at this locus can cause a syndrome restricted to progressive distal motor neuropathy without overt signs of systemic copper deficiency. This previously unrecognized genotype-phenotype correlation suggests an important role of the ATP7A copper transporter in motor-neuron maintenance and function. 相似文献
117.
Carlos A. Sánchez-Catasús José Cabrera-Gomez William Almaguer Melián José Luis Giroud Benítez Rafael Rodríguez Rojas Jorge Bosch Bayard Lídice Galán Reinaldo Galvizu Sánchez Nancy Pavón Fuentes Pedro Valdes-Sosa 《PloS one》2013,8(6)
Recent neuroimaging studies show that brain abnormalities in neuromyelitis optica (NMO) are more frequent than earlier described. Yet, more research considering multiple aspects of NMO is necessary to better understand these abnormalities. A clinical feature of relapsing NMO (RNMO) is that the incremental disability is attack-related. Therefore, association between the attack-related process and neuroimaging might be expected. On the other hand, the immunopathological analysis of NMO lesions has suggested that CNS microvasculature could be an early disease target, which could alter brain perfusion. Brain tissue volume changes accompanying perfusion alteration could also be expected throughout the attack-related process. The aim of this study was to investigate in RNMO patients, by voxel-based correlation analysis, the assumed associations between regional brain white (WMV) and grey matter volumes (GMV) and/or perfusion on one side, and the number of optic neuritis (ON) attacks, myelitis attacks and/or total attacks on the other side. For this purpose, high resolution T1-weighted MRI and perfusion SPECT imaging were obtained in 15 RNMO patients. The results showed negative regional correlations of WMV, GMV and perfusion with the number of ON attacks, involving important components of the visual system, which could be relevant for the comprehension of incremental visual disability in RNMO. We also found positive regional correlation of perfusion with the number of ON attacks, mostly overlapping the brain area where the WMV showed negative correlation. This provides evidence that brain microvasculature is an early disease target and suggests that perfusion alteration could be important in the development of brain structural abnormalities in RNMO. 相似文献
118.
Felipe Micali Nuvoloni Antonio Carlos Lofego José Marcos Rezende Reinaldo José Fazzio Feres 《分类学与生物多样性》2013,11(2):182-206
Despite the Amazon Forest being the largest tropical forest in the world, and cradle of rubber trees (Hevea brasiliensis), no studies have aimed to report the occurrence of mites associated with native trees from this ecosystem. Our survey investigates the phytoseiid mites associated with five species of native rubber trees from nine sites of the Amazon Forest, and also presents a major review of phytoseiid species from natural vegetation in Brazil. We found a total of 1305 mites, belonging to 30 species, of which seven were new to science, Amblydromalus akiri sp. nov., Amblyseius chicomendesi sp. nov., Amblyseius duckei sp. nov., Amblyseius manauara sp. nov., Iphiseiodes katukina sp. nov., Iphiseiodes raucuara sp. nov. and Typhlodromips igapo sp. nov.; beyond two new records for Brazil, Iphiseiodes kamahorae and Amblyseius martus. Our results emphasize the importance of Amazon native trees as an unexplored source of predator mites, which in turn may be further studied as biological control agents of pest mites on rubber trees. The impressive diversity, endemism and rate of new species found highlight the importance of studies on arthropod communities associated with the Amazon vegetation. 相似文献
119.
Guillermin Agüero-Chapin Reinaldo Molina-Ruiz Emanuel Maldonado Gustavo de la Riva Aminael Sánchez-Rodríguez Vitor Vasconcelos Agostinho Antunes 《PloS one》2013,8(7)
The introduction of two-dimension (2D) graphs and their numerical characterization for comparative analyses of DNA/RNA and protein sequences without the need of sequence alignments is an active yet recent research topic in bioinformatics. Here, we used a 2D artificial representation (four-color maps) with a simple numerical characterization through topological indices (TIs) to aid the discovering of remote homologous of Adenylation domains (A-domains) from the Nonribosomal Peptide Synthetases (NRPS) class in the proteome of the cyanobacteria Microcystis aeruginosa. Cyanobacteria are a rich source of structurally diverse oligopeptides that are predominantly synthesized by NPRS. Several A-domains share amino acid identities lower than 20 % being a possible source of remote homologous. Therefore, A-domains cannot be easily retrieved by BLASTp searches using a single template. To cope with the sequence diversity of the A-domains we have combined homology-search methods with an alignment-free tool that uses protein four-color-maps. TI2BioP (Topological Indices to
BioPolymers) version 2.0, available at http://ti2biop.sourceforge.net/ allowed the calculation of simple TIs from the protein sequences (four-color maps). Such TIs were used as input predictors for the statistical estimations required to build the alignment-free models. We concluded that the use of graphical/numerical approaches in cooperation with other sequence search methods, like multi-templates BLASTp and profile HMM, can give the most complete exploration of the repertoire of highly diverse protein families. 相似文献
120.
Natan Messias Almeida Cibele Cardoso Castro Ana Virgínia Leite Reinaldo Rodrigo Novo Isabel Cristina Machado 《Annals of botany》2013,112(6):1117-1123