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771.
772.
Effects of MEK inhibitor U0126 on meiotic progression in mouse oocytes: microtuble organization, asymmetric division and metaphase Ⅱ arrest 总被引:1,自引:0,他引:1
CHAO TONG HENG YU FAN DA YUAN CHEN XIANG FEN SONG HEIDE SCHATTEN QING YUAN SUNI State Key Laboratory of Reproductive Biology Institute of Zoology Chinese Academy of Sciences Beijing China. Department of Veterinary Pathobiology University of Missouri-Columbia MO USA 《Cell research》2003,13(5):375-384
In this study we used U0126, a potent and specific inhibitor of MEK, to study the roles of MEK/ERK/p90~(rsk) signaling pathway in the meiotic cell cycle of mouse oocytes. The phosphorylation of MAP kinase and p90~(rsk) in the oocytes treated with 1.5 μM U0126 was the same as that in oocytes cultured in drug-free medium. With 1.5 μM U0126 treatment, the spindles appeared normal as they formed in oocytes, but failed to maintain its structure. Instead, the spindle lost one pole or elongated extraordinarily. After further culture, some oocytes extruded gigantic polar bodies (>30 μm) that later divided into two small ones. Some oocytes underwent symmetric division and produced two equal-size daughter cells in which normal spindles formed. In oocytes with different division patterns, MAP kinase was normally phosphorylated. When the concentration of U0126 was increased to 15 mM, the phosphorylation of both MAPK and p90~(rsk) were inhibited, while symmetric division was decreased. When incubating in medium c 相似文献
773.
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775.
W. J. Drost D. J. Somers G. Rakow J. P. Raney 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(5):752-757
The fae1 gene codes for KCS (β-keto-acyl-CoA synthase), the candidate enzyme for elongation of oleic acid to eicosenoic acid and erucic
acid (C22:1) in various oilseed species. Degenerate primers for the fae1 gene were used to amplify and clone fae1 gene homologs in high and zero C22:1 Sinapis alba. Under stringent PCR conditions, a polymorphism was revealed between the two genotypes and was mapped as a fae1 marker in an F2 population derived from a cross between high and zero C22:1 S. alba. The fae1 marker co-segregated with C22:1 content and the C22:1 phenotypic locus. In addition, a set of 11 RAPD markers for C22:1 in
S. alba was identified. Cloning and sequencing of the fae1 alleles in high and zero C22:1 S. alba revealed two amino-acid substitutions specific to zero C22:1 S. alba. The underlying nucleotide substitution for one of the amino-acid substitutions and an adjacent silent nucleotide substitution
were used to design primers for allele-specific amplicons for both the wild-type and zero C22:1 alleles. The two diagnostic
PCR tests are reliable selection tools to identify S. alba carrying one or both of the wild-type and mutant C22:1 alleles of the KCS gene.
Received: 27 July 2000 / Accepted: 1 February 2001 相似文献
776.
Survey of Malassezia sp and dermatophytes in the cutaneous microbiome of free‐ranging golden‐headed lion tamarins (Leontopithecus chrysomelas ‐ Kuhl, 1820) 下载免费PDF全文
777.
778.
Somers DJ Thomas J Depauw R Fox S Humphreys G Fedak G 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(8):1623-1631
Fusarium head blight of wheat is a major deterrent to wheat production world-wide. The genetics of FHB resistance in wheat
are becoming clear and there is a good understanding of the genome location of FHB resistance QTL from different sources such
as Sumai3, Wuhan, Nyubai and Frontana. All the components needed for assembling complex genotypes through large-scale molecular
breeding experiments are now available. This experiment used high throughput microsatellite genotyping and half-seed analysis
to process four independent crosses through a molecular breeding strategy to introduce multiple pest resistance genes into
Canadian wheat. This included two backcrosses and selection for a total of six FHB resistance QTL, orange blossom wheat midge
resistance (Sm1) and leaf rust resistance (Lr21). In addition, the fixation of the elite genetic background was monitored with 45–76 markers to accelerate restoration of
the genetic background at each backcross. The strategy resulted in 87% fixation of the elite genetic background on average
at the BC2F1 generation and successfully introduced all of the chromosome segments containing FHB, Sm1 and Lr21 resistance genes. The molecular breeding strategy was completed in 25 months, at an equal pace to conventional crossing and
selection of spring wheat. 相似文献
779.
Allelic reduction and genetic shift in the Canadian hard red spring wheat germplasm released from 1845 to 2004 总被引:10,自引:0,他引:10
Fu YB Peterson GW Richards KW Somers D DePauw RM Clarke JM 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,110(8):1505-1516
Analysis of genetic diversity changes in existing gene pools of cultivated crops is important for understanding the impact of plant breeding on crop genetic diversity and developing effective indicators for genetic diversity of cultivated plants. The objective of this study was to assess genetic diversity changes in 75 Canadian hard red wheat (Triticum aestivum L.) cultivars released from 1845 to 2004 using 31 simple sequence repeats (SSRs) markers. A total of 267 SSR alleles were detected, and their allelic frequencies ranged from 0.01 to 0.97, with an average of 0.14. Significant allelic reduction was observed at only four SSR loci for the cultivars released from 1970 onwards. However, 51 alleles (about 19%) present in pre-1910 cultivars were undetected in cultivars released after 1990 and were spread over 27 SSR loci. The proportion of SSR variation accounted for by six breeding periods was 12.5%, by four ancestral families, 16.5%, and by eight breeding programs, 8.4%. The average genetic diversity measured by three different band-sharing methods did not change significantly among cultivars released from different breeding periods, breeding programs, and ancestral families. However, genetic shift was obvious in the cultivars released over the six breeding periods, reflecting well the various breeding efforts over years. These results clearly show the allelic reduction and genetic shift in the Canadian hard red spring wheat germplasm released over time. Consequently, more effort needs to be made to broaden the wheat breeding base and conserve wheat germplasm. 相似文献
780.
The apoptotic ligands TRAIL,TWEAK, and Fas ligand mediate monocyte death induced by autologous lupus T cells 总被引:14,自引:0,他引:14
Kaplan MJ Lewis EE Shelden EA Somers E Pavlic R McCune WJ Richardson BC 《Journal of immunology (Baltimore, Md. : 1950)》2002,169(10):6020-6029
Individuals with systemic lupus erythematosus show evidence of a significant increase in monocyte apoptosis. This process is mediated, at least in part, by an autoreactive T cell subset that kills autologous monocytes in the absence of nominal Ag. We have investigated the apoptotic pathways involved in this T cell-mediated process. Expression of the apoptotic ligands TRAIL, TNF-like weak inducer of apoptosis (TWEAK), and Fas ligand on lupus T cells was determined, and the role of these molecules in the monocyte apoptotic response was examined. We report that these apoptotic ligands mediate the autologous monocyte death induced by lupus T cells and that this cytotoxicity is associated with increased expression of these molecules on activated T cells, rather than with an increased susceptibility of lupus monocytes to apoptosis induced by these ligands. These results define novel mechanisms that contribute to increased monocyte apoptosis characterizing patients with lupus. We propose that this mechanism could provide a source of potentially antigenic material for the autoimmune response and interfere with normal clearing mechanisms. 相似文献