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排序方式: 共有365条查询结果,搜索用时 15 毫秒
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Zdenek Petrásek Franz-Josef Schmitt Christoph Theiss Joachim Huyer Min Chen Anthony Larkum Hans Joachim Eichler Klaus Kemnitz Hann-J?rg Eckert 《Photochemical & photobiological sciences》2005,4(12):1016-1022
The fluorescence decay spectra and the excitation energy transfer from the phycobiliproteins (PBP) to the chlorophyll-antennae of intact cells of the chlorophyll (Chl) d-dominated cyanobacterium Acaryochloris marina were investigated at 298 and 77 K by time- and wavelength-correlated single photon counting fluorescence spectroscopy. At 298 K it was found that (i) the fluorescence dynamics in A. marina is characterized by two emission peaks located at about 650 and 725 nm, (ii) the intensity of the 650 nm fluorescence depends strongly on the excitation wavelength, being high upon excitation of phycobiliprotein (PBP) at 632 nm but virtually absent upon excitation of chlorophyll at 430 nm, (iii) the 650 nm fluorescence band decayed predominantly with a lifetime of 70 +/- 20 ps, (iv) the 725 nm fluorescence, which was observed independent of the excitation wavelength, can be described by a three-exponential decay kinetics with lifetimes depending on the open or the closed state (F(0) or F(m)) of the reaction centre of Photosystem II (PS II). Based on the results of this study, it is inferred that the excitation energy transfer from phycobiliproteins to Chl d of PS II in A. marina occurs with a time constant of about 70 ps, which is about three times faster than the energy transfer from the phycobilisomes to PS II in the Chl a-containing cyanobacterium Synechococcus 6301. A similar fast PBP to Chl d excitation energy transfer was also observed at 77 K. At 77 K a small long-lived fluorescence decay component with a lifetime of 14 ns was observed in the 640-700 nm spectral range. However, it has a rather featureless spectrum, not typical for Chl a, and was only observed upon excitation at 400 nm but not upon excitation at 632 and 654 nm. Thus, this long-lived fluorescence component cannot be used as an indicator that the primary PS II donor of Acaryochloris marina contains Chl a. 相似文献
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Genome Duplications and Other Features in 12 Mb of DNA Sequence from Human Chromosome 16p and 16q 总被引:7,自引:0,他引:7
Brendan J. Loftus Ung-Jin Kim Victoria P. Sneddon Francis Kalush Rhonda Brandon Joyce Fuhrmann Tanya Mason Marie L. Crosby Mary Barnstead Lisa Cronin Anne Deslattes Mays Yicheng Cao Robert X. Xu Hyung-Lyun Kang Steve Mitchell Evan E. Eichler Peter C. Harris J. Craig Venter Mark D. Adams 《Genomics》1999,60(3):295-308
Several publicly funded large-scale sequencing efforts have been initiated with the goal of completing the first reference human genome sequence by the year 2005. Here we present the results of analysis of 11.8 Mb of genomic sequence from chromosome 16. The apparent gene density varies throughout the region, but the number of genes predicted (84) suggests that this is a gene-poor region. This result may also suggest that the total number of human genes is likely to be at the lower end of published estimates. One of the most interesting aspects of this region of the genome is the presence of highly homologous, recently duplicated tracts of sequence distributed throughout the p-arm. Such duplications have implications for mapping and gene analysis as well as the predisposition to recurrent chromosomal structural rearrangements associated with genetic disease. 相似文献
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Giuliana Giannuzzi Glennis A Logsdon Nicolas Chatron Danny E Miller Julie Reversat Katherine M Munson Kendra Hoekzema Marie-Noëlle Bonnet-Dupeyron Pierre-Antoine Rollat-Farnier Carl A Baker Damien Sanlaville Evan E Eichler Caroline Schluth-Bolard Alexandre Reymond 《Molecular biology and evolution》2021,38(12):5576
Human centromeres are mainly composed of alpha satellite DNA hierarchically organized as higher-order repeats (HORs). Alpha satellite dynamics is shown by sequence homogenization in centromeric arrays and by its transfer to other centromeric locations, for example, during the maturation of new centromeres. We identified during prenatal aneuploidy diagnosis by fluorescent in situ hybridization a de novo insertion of alpha satellite DNA from the centromere of chromosome 18 (D18Z1) into cytoband 15q26. Although bound by CENP-B, this locus did not acquire centromeric functionality as demonstrated by the lack of constriction and the absence of CENP-A binding. The insertion was associated with a 2.8-kbp deletion and likely occurred in the paternal germline. The site was enriched in long terminal repeats and located ∼10 Mbp from the location where a centromere was ancestrally seeded and became inactive in the common ancestor of humans and apes 20–25 million years ago. Long-read mapping to the T2T-CHM13 human genome assembly revealed that the insertion derives from a specific region of chromosome 18 centromeric 12-mer HOR array in which the monomer size follows a regular pattern. The rearrangement did not directly disrupt any gene or predicted regulatory element and did not alter the methylation status of the surrounding region, consistent with the absence of phenotypic consequences in the carrier. This case demonstrates a likely rare but new class of structural variation that we name “alpha satellite insertion.” It also expands our knowledge on alphoid DNA dynamics and conveys the possibility that alphoid arrays can relocate near vestigial centromeric sites. 相似文献
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Hominoid chromosomal rearrangements on 17q map to complex regions of segmental duplication 总被引:1,自引:0,他引:1 下载免费PDF全文
Cardone MF Jiang Z D'Addabbo P Archidiacono N Rocchi M Eichler EE Ventura M 《Genome biology》2008,9(2):R28
Background
Chromosomal rearrangements, such as translocations and inversions, are recurrent phenomena during evolution, and both of them are involved in reproductive isolation and speciation. To better understand the molecular basis of chromosome rearrangements and their part in karyotype evolution, we have investigated the history of human chromosome 17 by comparative fluorescence in situ hybridization (FISH) and sequence analysis. 相似文献50.