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91.
Maciel DM Rodrigues ML Wait R Villas Boas MH Tischer CA Barreto-Bergter E 《Archives of biochemistry and biophysics》2002,405(2):205-213
Magnaporthe grisea is a fungal pathogen that infects rice leaves and causes rice blast, a devastating crop disease. M. grisea produces active elicitors of the hypersensitive response in rice that were previously identified as ceramide monohexosides (CMHs). Using several chromatographic approaches, mass spectrometry, and nuclear magnetic resonance, we identified ceramide mono- and dihexosides (CDH) in purified lipid extracts from M. grisea cells. As described by other authors, CMH consists of a ceramide moiety containing 9-methyl-4,8-sphingadienine in amidic linkage to 2-hydroxyoctadecenoic or 2-hydroxyhexadecenoic acids and a carbohydrate segment consisting of one residue of glucose. CDHs, however, contain beta-galactose (1-->4)-linked to beta-glucose as sugar units and phytosphingosine as the long-chain base, bound to a C24 alpha-hydroxylated fatty acid. To our knowledge, this is the first report on the occurrence of CDH in a fungal species and illustrates the existence of an alternative path of ceramide glycosylation in fungal cells. 相似文献
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93.
Rewardless orchid species are pollinated by deception and have reduced reproductive success. Those species that present self-compatibility followed by alternative mechanisms of autogamy may compensate for such episodic allogamy events. This is the case for rain-assisted self-pollination, a rare mechanism in Orchidaceae. In this study, we investigated the reproductive biology of two terrestrial species: Cyrtopodium hatschbachii and C. paludicolum. We studied their reproductive systems, examined pollinators and male and female successes, and ascertained if rain promotes self-pollination. Both species are allogamous but self-compatible. However, natural fruit set is low, not exceeding 1.40% during 4 years of observation. This may result from the reduced frequency of pollinator visitation followed by a high pollinator specificity, because each species was pollinated by a single specialist bee. Although spontaneous selfing did not occur, we verified fruits formed by rain action. The evaporation of the water droplet that accumulates on stigma helps the pollinarium to slip back, promoting selfing. This occurred in approximately 10% of C. hatschbachii fruits, but in C. paludicolum it was recorded only once during three observation years. This indicates that the phenomenon happens at random and may vary temporally. Nevertheless, rain may confer additional fruit set, especially under circumstances of pollinator limitation. Overall, we confirmed deception as a strategy for this understudied genus. In addition, we report a further two cases of rain-assisted self-pollination for Cyrtopodium, for species from the center of diversity of the genus, indicating that it may be more widespread than previously thought. 相似文献
94.
Hermínio Souza Rocha Edson Ampélio Pozza Cleilson Do Nascimento Uchôa Zilton José Maciel Cordeiro Paulo Estevão De Souza ÂNgelo Aparecido Barbosa Sussel Carlos Alberto De Rezende 《Journal of Phytopathology》2012,160(6):277-285
An understanding of the progression of a disease is important in the adoption of control strategies as well as the evaluation of their efficacies. Temporal analysis is especially useful because it integrates the evolution of the interaction between the components of the pathosystem, as expressed by the accumulated data on the incidence and severity of disease and depicted by the disease progression curve. Within a given patho‐system, the dispersed airborne spores are important components in the progress of plant disease epidemics. Our aims were to evaluate the temporal dynamics of yellow Sigatoka in a banana plantation located in Coronel Pacheco, MG, Brazil, and to assess the aerobiology of Mycosphaerella musicola spores throughout the year. During the rainy season, we observed intense disease progression concomitant with high rates of leaf emission, which caused rapid reversal of the severity peaks after the maximum rates were reached. The yellow Sigatoka progress curve showed two peaks of extreme severity. The first, which occurred during the rainy season, was predominantly caused by a high concentration of conidia. The second, which occurred during the dry season, was predominantly caused by a high concentration of ascospores in the air. The ascospore concentrations were correlated with the severity of the disease 29 days later, indicating the average latency period of the disease in that region. The patterns of the severity curves for both peaks fit the monomolecular model, and the progression rates were higher during the rainy season than the dry season. The spore concentrations were the same at the two evaluated heights. In all evaluations, it was observed a higher concentration of ascospores than of conidia, with the greatest ascospore concentrations occurring during the early hours of the day and the greatest conidia concentrations occurring later, after the dew has dropped from the leaves. 相似文献
95.
Phylogenetic relationships of the largest lungless tetrapod (Gymnophiona,Atretochoana) and the evolution of lunglessness in caecilians 下载免费PDF全文
Adriano O. Maciel Maria I. C. Sampaio Marinus S. Hoogmoed Horacio Schneider 《Zoologica scripta》2017,46(3):255-263
Atretochoana eiselti is the largest extant lungless tetrapod. This species is one of the fully aquatic caecilian amphibians of the family Typhlonectidae. It is unique within Gymnophiona in lacking lungs and having sealed choanae, a snake‐like postoccipital jaw articulation, and some other greatly divergent features. Phylogenetic relationships of the five typhlonectid genera have been estimated only once previously, in an analysis of morphological data. Here we infer for the first time integrating molecular and morphological data, the relationships of all typhlonectid genera. Although Atretochoana and Potomotyphlus share several derived character states in morphology, some of which linked to a reduction of the pulmonary importance in respiration, Potomotyphlus is more closely related to Typhlonectes than to Atretochoana. Consequently, we conclude that evolutionary loss of lungs or gradual reduction of their importance in respiration in Atretochoana and Potomotyphlus was convergent within this poorly known group of amphibians. 相似文献
96.
Alessandra Becker Finco Ricardo Andrez Machado-de-Ávila Rayana Maciel Juliana De Moura Philippe Billiald Andrea Emilia Marques Stinghen Larissa M. Alvarenga 《Biochemistry and Biophysics Reports》2016
Advanced Glycation End Products (AGEs) are toxins that are involved in structural and functional alterations of several organs and tissues, resulting in various pathologies. Several types of AGEs have been described but carboxymethyllysine (CML) is the major antigenic AGE compound. In this study, three different immunogenic carrier proteins (KLH, keyhole limpet hemocyanin; BSA, bovine serum albumin; and HSA, human serum albumin) were modified by glycation. The glycated molecules were used to produce epitope-specific monoclonal antibodies able to recognize the CML domain and to detect uremic toxins in the serum of patients with chronic kidney disease (CKD). A competitive ELISA was standardized in order to quantify CML in the sera of CKD patients. An increase in uremic toxins can compromise the clinical condition of these patients, thus, the detection and quantification of these toxins should contribute to a better management and understanding of this disease. 相似文献
97.
Michelle N Knowlton Tongbin Li Yongliang Ren Brent R Bill Lynda BM Ellis Stephen C Ekker 《BMC bioinformatics》2008,9(1):7
Background
The zebrafish is a powerful model vertebrate amenable to high throughput in vivo genetic analyses. Examples include reverse genetic screens using morpholino knockdown, expression-based screening using enhancer trapping and forward genetic screening using transposon insertional mutagenesis. We have created a database to facilitate web-based distribution of data from such genetic studies. 相似文献98.
Spinocerebellar ataxia type-3, also known as Machado-Joseph Disease (MJD), is one of many inherited neurodegenerative disorders caused by polyglutamine-encoding CAG repeat expansions in otherwise unrelated genes. Disease protein misfolding and aggregation, often within the nucleus of affected neurons, characterize polyglutamine disorders. Several evidences have implicated the nucleus as the primary site of pathogenesis for MJD. However, the molecular determinants for the nucleocytoplasmic transport of human ataxin-3 (Atx3), the protein which is mutated in patients with MJD, are not characterized.In order to characterize the nuclear shuttling activity of Atx3, we performed yeast nuclear import assays and found that Atx3 is actively imported into the nucleus, by means of a classical nuclear localizing sequence formed by a cluster of lysine and arginine residues. On the other hand, when active nuclear export was inhibited using leptomycin B, a specific inhibitor of the nuclear export receptor CRM1, both endogenous Atx3 and transfected GFP-Atx3 accumulated inside the nucleus of a subpopulation of COS-7 cells, whereas both proteins are normally predominant in the cytoplasm.Additionally, using a Rev(1.4)-GFP nuclear export assay, we performed an extensive analysis of six putative aliphatic nuclear export motifs identified in Atx3 amino acid sequence. Although none of the tested peptide sequences were found to drive nuclear export when isolated, we have successfully mapped the region of Atx3 responsible for its CRM1-independent nuclear export activity. Curiously, the N-terminal Josephin domain alone is exported into the cytoplasm, but the nuclear export activity of Atx3 is significantly enhanced in a longer construct that is truncated after the two ubiquitin interaction motifs, upstream from the polyQ tract.Our data show that Atx3 is actively imported to and exported from the cell nucleus, and that its nuclear export activity is dependent on a motif located at its N-terminal region. Since pathological Atx3 aggregates in the nucleus of affected neurons in MJD, and there is in vivo evidence that nuclear localization of Atx3 is required for the manifestation of symptoms in MJD, defects in the nucleocytoplasmic shuttling activity of the protein may be involved in the nuclear accumulation and aggregation of expanded Atx3. 相似文献
99.
100.
Fernanda Mattos de Souza Thiago Nascimento do Prado Jair dos Santos Pinheiro Renata Lyrio Peres Thamy Carvalho Lacerda Rafaela Borge Loureiro Jose Américo Carvalho Geisa Fregona Elias Santos Dias Lorrayne Beliqui Cosme Rodrigo Ribeiro Rodrigues Lee Wood Riley Ethel Leonor Noia Maciel 《PloS one》2014,9(8)