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991.
992.
The chromosomes of 31 species of Passiflora, distributed throughout the subgenera Astrophea, Calopathanthus, Distephana, Dysosmia, Passiflora, Plectostemma and Tacsonia were analysed. Three different karyotypes were observed: 2n = 12, 24, 36; 2n = 18, 72 and 2n = 20. The karyotype of these
species was almost always constituted of metacentric and submetacentric chromosomes with variable karyotype symmetry. In the
group with x = 6, represented by the subgenus Plectostemma, six diploid species with 2n = 12, one tetraploid with 2n = 24 (P. suberosa) and an intraspecific polyploid with 2n = 12, 36 (P. misera) were analysed. P. pentagona (subgenus Astrophea) may also be included in this karyological group since it presents 2n = 24 and may be of polyploid origin, with x = 6. The
interphase nuclei in this group were areticulate, except those of P. morifolia and P. pentagona with semi-reticulate characteristics. Two small terminal heterochromatic blocks, positive for chromomycin A3, were identified in the largest chromosome pair of P. capsularis and P. rubra, species very closely related, while P. tricuspis displayed four chromosomes with proximal blocks. In the group with x = 9, represented mainly by subgenus Passiflora, 20 species with 2n = 18 and one with 2n = 72 were studied. They presented chromosomes larger than those species with x = 6
and interphase nuclei of semi-reticulate type, except for P. mixta with areticulate nuclei. Four terminal CMA+ blocks were observed in P. edulis, six blocks in P. caerulea and P. racemosa, while five blocks were observed in the single P. amethystina plant analysed. P. foetida (subgenus Dysosmia), the only species with 2n = 20, exhibited six chromosomes with CMA+ blocks and interphase nuclei of the areticulate type. The meiotic analysis of representatives of the three groups (P. foetida, P. suberosa, P. cincinnata and P. racemosa) always presented regular pairing and regular chromosome segregation, except in P. jilekii where a tetravalent was observed. The analysis of the chromosome variation within the genus and the family suggests that
the base number of Passiflora may be x1 = 6 or x1 = 12, whereas x2 = 9 is only an important secondary base number.
Received April 11, 2000 Accepted October 5, 2000 相似文献
993.
Mariana A. de Matos Tamiris C. Duarte Vinícius de O. Ottone Pmela F. da M. Sampaio Karine B. Costa Marcos F. Andrade de Oliveira Pope L. Moseley Suzanne M. Schneider Cndido C. Coimbra Gustavo E. A. Brito‐Melo Flvio de C. Magalhes Fabiano T. Amorim Etel Rocha‐Vieira 《Cell biochemistry and function》2016,34(4):209-216
994.
Catarina Addobbati Jordão Cavalcanti Jaqueline de Azevêdo Silva Will de Barros Pita Tiago Degani Veit Odirlei Andre Monticielo Ricardo Machado Xavier João Carlos Tavares Brenol Cleiton Viegas Brenol Thiago Sotero Fragoso Alexandre Domingues Barbosa Ângela Luiza Branco Pinto Duarte Renê Donizeti Ribeiro Oliveira Paulo Louzada-Júnior Eduardo Antônio Donadi Sergio Crovella José Artur Bogo Chies Paula Sandrin-Garcia 《Molecular biology reports》2016,43(1):41-51
995.
Marion Gransagne Gabriel Aym Sbastien Brier Gaëlle Chauveau-Le Friec Vronique Meriaux Mireille Nowakowski Franois Dejardin Sylvain Levallois Guilherme Dias de Melo Flora Donati Matthieu Prot Sbastien Brûl Bertrand Raynal Jacques Bellalou Pedro Goncalves Xavier Montagutelli James P. Di Santo Franoise Lazarini Patrick England Stphane Petres Nicolas Escriou Pierre Lafaye 《The Journal of biological chemistry》2022,298(1)
The current COVID-19 pandemic illustrates the importance of obtaining reliable methods for the rapid detection of SARS-CoV-2. A highly specific and sensitive diagnostic test able to differentiate the SARS-CoV-2 virus from common human coronaviruses is therefore needed. Coronavirus nucleoprotein (N) localizes to the cytoplasm and the nucleolus and is required for viral RNA synthesis. N is the most abundant coronavirus protein, so it is of utmost importance to develop specific antibodies for its detection. In this study, we developed a sandwich immunoassay to recognize the SARS-CoV-2 N protein. We immunized one alpaca with recombinant SARS-CoV-2 N and constructed a large single variable domain on heavy chain (VHH) antibody library. After phage display selection, seven VHHs recognizing the full N protein were identified by ELISA. These VHHs did not recognize the nucleoproteins of the four common human coronaviruses. Hydrogen Deuterium eXchange–Mass Spectrometry (HDX-MS) analysis also showed that these VHHs mainly targeted conformational epitopes in either the C-terminal or the N-terminal domains. All VHHs were able to recognize SARS-CoV-2 in infected cells or on infected hamster tissues. Moreover, the VHHs could detect the SARS variants B.1.17/alpha, B.1.351/beta, and P1/gamma. We propose that this sandwich immunoassay could be applied to specifically detect the SARS-CoV-2 N in human nasal swabs. 相似文献
996.
Several predatory mites have been found in association with the coconut mite, Aceria guerreronis Keifer, in northeast Brazil. However, the latter still causes damage to coconut in that region. The objectives of this work
were to compare the frequencies of occurrence of Neoseiulus (Phytoseiidae) and Proctolaelaps (Melicharidae) species on standing and aborted coconuts in coastal Pernambuco State, northeast Brazil and to analyze their
possible limitations as control agents of the coconut mite, based on evaluations of the restrictions they may have to access
the microhabitat inhabited by the pest and their functional and reproductive responses to increasing densities of the latter.
Neoseiulus baraki (Athias-Henriot) was found mostly on standing coconuts whereas Proctolaelaps bickleyi (Bram) was found mostly on aborted coconuts. Measurements of the entrance to the microhabitat occupied by the coconut mite,
between the bracts and the subjacent fruit surface, showed that this different pattern of predator prevalence could be related
to predator sizes, although other environmental factors could not be disregarded. Progressively higher predation rate of N. baraki was observed up to an experimental density that corresponded to 1,200 coconut mites per fruit, which is close to the average
number determined in northeast Brazil, reducing slightly afterwards. Predation rate of P. bickleyi reduced consistently but slightly with increasing prey densities, but in absolute values, rates were always much higher than
determined for N. baraki. The excessively high killing capacity of P. bickleyi, probably related to its high feeding requirement, may be detrimental in terms of stability. In fact, such high requirement
for food suggests that P. bickleyi might not have a strong relation with the coconut mite and that the latter may not be its main food source under natural
conditions. It is concluded that body sizes of both predators and the exceedingly high feeding requirement of P. bickleyi may limit their performance as control agents of the coconut mite. 相似文献
997.
Karadimas CL Vu TH Holve SA Chronopoulou P Quinzii C Johnsen SD Kurth J Eggers E Palenzuela L Tanji K Bonilla E De Vivo DC DiMauro S Hirano M 《American journal of human genetics》2006,79(3):544-548
Navajo neurohepatopathy (NNH) is an autosomal recessive disease that is prevalent among Navajo children in the southwestern United States. The major clinical features are hepatopathy, peripheral neuropathy, corneal anesthesia and scarring, acral mutilation, cerebral leukoencephalopathy, failure to thrive, and recurrent metabolic acidosis with intercurrent infections. Infantile, childhood, and classic forms of NNH have been described. Mitochondrial DNA (mtDNA) depletion was detected in the livers of two patients, suggesting a primary defect in mtDNA maintenance. Homozygosity mapping of two families with NNH suggested linkage to chromosome 2p24. This locus includes the MPV17 gene, which, when mutated, causes a hepatocerebral form of mtDNA depletion. Sequencing of the MPV17 gene in six patients with NNH from five families revealed the homozygous R50Q mutation described elsewhere. Identification of a single missense mutation in patients with NNH confirms that the disease is probably due to a founder effect and extends the phenotypic spectrum associated with MPV17 mutations. 相似文献
998.
Catarina Ginja Maria CT Penedo Maria F Sobral José Matos Carla Borges Dina Neves Teresa Rangel-Figueiredo Alfredo Cravador 《遗传、选种与进化》2010,42(1):18
Background
Decisions to initiate conservation programmes need to account for extant variability, diversity loss and cultural and economic aspects. Molecular markers were used to investigate if putative Algarvia animals could be identified for use as progenitors in a breeding programme to recover this nearly extinct breed.Methods
46 individuals phenotypically representative of Algarvia cattle were genotyped for 27 microsatellite loci and compared with 11 Portuguese autochthonous and three imported breeds. Genetic distances and factorial correspondence analyses (FCA) were performed to investigate the relationship among Algarvia and related breeds. Assignment tests were done to identify representative individuals of the breed. Y chromosome and mtDNA analyses were used to further characterize Algarvia animals. Gene- and allelic-based conservation analyses were used to determine breed contributions to overall genetic diversity.Results
Genetic distance and FCA results confirmed the close relationship between Algarvia and southern Portuguese breeds. Assignment tests without breed information classified 17 Algarvia animals in this cluster with a high probability (q > 0.95). With breed information, 30 cows and three bulls were identified (q > 0.95) that could be used to reconstitute the Algarvia breed. Molecular and morphological results were concordant. These animals showed intermediate levels of genetic diversity (MNA = 6.0 ± 1.6, Rt = 5.7 ± 1.4, Ho = 0.63 ± 0.19 and He = 0.69 ± 0.10) relative to other Portuguese breeds. Evidence of inbreeding was also detected (Fis = 0.083, P < 0.001). The four Algarvia bulls had Y-haplotypes H6Y2 and H11Y2, common in Portuguese cattle. The mtDNA composition showed prevalence of T3 matrilines and presence of the African-derived T1a haplogroup. This analysis confirmed the genetic proximity of Algarvia and Garvonesa breeds (Fst = 0.028, P > 0.05). Algarvia cattle provide an intermediate contribution (CB = 6.18, CW = -0.06 and D1 = 0.50) to the overall gene diversity of Portuguese cattle. Algarvia and seven other autochthonous breeds made no contribution to the overall allelic diversity.Conclusions
Molecular analyses complemented previous morphological findings to identify 33 animals that can be considered remnants of the Algarvia breed. Results of genetic diversity and conservation analyses provide objective information to establish a management program to reconstitute the Algarvia breed. 相似文献999.
INTRODUCTION: Echinococcus granulosus species has a wide variety in both geography and hosts; indeed, 10 genotypes have been reported in studies on material of animal origin. The aim of this study was to genotype E. granulosus obtained from human hydatid cysts. MATERIALS AND METHODS: The hydatid fluid and sand was collected from patients who underwent surgery for hepatic and pulmonary hydatidosis at Hospital Regional in Temuco, Chile, between 2004 and 2005. Two PCR systems were used: PCR Eg 9 and PCR Eg 16. The RsaI enzyme was used for RFLP. The genotype was confirmed using the sequence of one fragment of 366 bp from a mitochondrial gene (cox1). RESULTS: The DNA of protoscolices from 24 samples was analyzed, 4 of them from pulmonary cysts and 20 from hepatic cysts. The 366 bp fragment was amplified in 20 out of 24 samples (83.3%). Enzymatic digestion revealed the presence of 3 possible genotypes: in 20 out of 21 samples (95,2%), a restriction was observed corresponding to the G1 or G7 genotypes; in the remaining sample genotype G4 or G7 was observed. Sequencing confirmed the presence of G1 genotype for 19 samples and G6 genotype for the remaining sample (G4 or G7 according to PCR-RFLP). CONCLUSION: The PCR-RFLP technique enabled three possible genotypes present (G1 or G7, G4 or G7) to be established. Sequencing allowed us to decisively identify the G1 and G6 genotypes in our study group. Previous studies agree with the identification of the G1 genotype in our country. We consider it significant that the G6 genotype is present in Chile for its epidemiological implications. 相似文献
1000.
Lin CC Melo FA Ghosh R Suen KM Stagg LJ Kirkpatrick J Arold ST Ahmed Z Ladbury JE 《Cell》2012,149(7):1514-1524
Receptor tyrosine kinase activity is known to occur in the absence of extracellular stimuli. Importantly, this "background" level of receptor phosphorylation is insufficient to effect a downstream response, suggesting that strict controls are present and prohibit full activation. Here a mechanism is described in which control of FGFR2 activation is provided by the adaptor protein Grb2. Dimeric Grb2 binds to the C termini of two FGFR2 molecules. This heterotetramer is capable of a low-level receptor transphosphorylation, but C-terminal phosphorylation and recruitment of signaling proteins are sterically hindered. Upon stimulation, FGFR2 phosphorylates tyrosine residues on Grb2, promoting dissociation from the receptor and allowing full activation of downstream signaling. These observations establish a role for Grb2 as an active regulator of RTK signaling. 相似文献