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Mark J. Guiltinan John C. Thomas Craig L. Nessler Terry L. Thomas 《Plant molecular biology》1989,13(5):605-610
Nuclear proteins from bean (Phaseolus vulgarus) embryos bind specifically to a 55 bp DNA sequence located upstream of the seed storage protein gene phaseolin. This sequence is capable of elevating gene expression in transgenic tobacco plants by as much as 150-fold when fused to a chimeric -glucuronidase reporter gene. Results presented in this paper demonstrate that nuclear extracts from carrot embryos bind to a phaseolin DNA sequence that includes a phaseolin activator sequence. This specific DNA binding activity is modulated during somatic embryogenesis. Two separable protein species react specifically with the labeled phaseolin DNA fragment (58.0 and 51.7 dDa). These results suggest that the cis- and trans-acting elements controlling gene expression have been highly conserved during evolution.Abbreviations bp
base pairs
- CAMV
cauliflower mosaic virus
- GUS
-glucuronidase
- kDa
kilodalton
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis 相似文献
154.
To investigate early events of Agrobacterium-mediated transformation of apple cultivars, a synthetic green fluorescent protein gene (SGFP) was used as a highly sensitive, vital reporter gene. Leaf explants from four apple cultivars (Delicious, Golden Delicious, Royal Gala and Greensleeves) were infected with Agrobacterium EHA101 harboring plasmid pDM96.0501. Fluorescence microscopy indicated that SGFP expression was first detected 48 h after infection and quantitative analysis revealed a high T-DNA transfer rate. Plant cells with stably incorporated T-DNA exhibited cell division and developed transgenic calli, followed by formation of transgenic shoots at low frequencies. The detection of SGFP expression with an epifluorescence stereomicroscope confirmed the effectiveness of SGFP as a reporter gene for detection of very early transformation events and for screening of putative transformants. The efficiency of the transformation and regeneration process decreased ca. 10000-fold from Agrobacterium infection to transgenic shoot regeneration, suggesting that factors other than Agrobacterium interaction and T-DNA transfer are rate-limiting steps in Agrobacterium-mediated transformation of apple. 相似文献
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157.
The chaetognaths, or arrowworms, constitute a small and enigmatic phylum of
marine invertebrates whose phylogenetic affinities have long been
uncertain. A popular hypothesis is that the chaetognaths are the sister
group of the major deuterostome phyla: chordates, hemichordates, and
echinoderms. Here we attempt to determine the affinities of the
chaetognaths by using molecular sequence data. We describe the isolation
and nucleotide sequence determination of 18S ribosomal DNA from one species
of chaetognath and one acanthocephalan. Extensive phylogenetic analyses
employing a suite of phylogenetic reconstruction methods (maximum
parsimony, maximum likelihood, evolutionary parsimony, and two distance
methods) suggest that the hypothesized relationship between chaetognaths
and the deuterostomes is incorrect. In contrast, we propose that the
lineage leading to the chaetognaths arose prior to the advent of the
coelomate metazoa.
相似文献
158.
159.
A phylogenetic survey using the polymerase chain reaction (PCR) has
identified four major P element subfamilies in the saltans and willistoni
species groups of Drosophila. One subfamily, containing about half of the
sequences studied, consists of elements that are very similar to the
canonical (and active) P element from D. melanogaster. Within this
subfamily, nucleotide sequence differentiation among different copies from
the same species and among elements from different species is relatively
low. This observation suggests that the canonical elements are relatively
recent additions to the genome or, less likely, are evolving slowly
relative to the other subfamilies. Elements belonging to the three
noncanonical lineages are distinct from the canonical elements and from one
another. Furthermore, there is considerably more sequence variation, on the
average, within the noncanonical subfamilies compared to the canonical
elements. Horizontal transfer and the coexistence of multiple,
independently evolving element subfamilies in the same genome may explain
the distribution of P elements in the saltans and willistoni species
groups. Such explanations are not mutually exclusive, and each may be
involved to varying degrees in the maintenance of P elements in natural
populations of Drosophila.
相似文献
160.
Siela N. Maximova Ann Young Sharon Pishak Mark J. Guiltinan 《In vitro cellular & developmental biology. Plant》2008,44(6):487-493
Somatic embryogenesis is an in vitro clonal propagation method with potential to contribute to the improvement of cacao varieties. Before using this technology
for commercial production, it is essential that somatic embryogenesis-derived plants be tested in field conditions. Therefore,
we established a field test at Union Vale Estate, Saint Lucia. Thirty- to 50-yr-old trees were selected for clonal propagation
as potentially high yielding based on local farmers observations. Clonal plants were propagated in vitro from immature flowers by embryogenesis and micropropagation. Multiple plants from nine genotypes were acclimated to greenhouse
conditions then returned to Saint Lucia and planted in a field. Orthotropic rooted cuttings and locally propagated open pollinated
seedlings were also planted for a total of 214 trees. Growth data were collected every 4–6 mo. including: stem diameter, stem
height, length of the longest jorquette branch, number of jorquette branches, and dates of first flowering and fruiting. At
4.5 yr after planting in the field there were no major differences in all growth parameters among the propagation methods
evaluated with exception of the orthotropic rooted cuttings. Trees grown from seeds were slightly taller then trees propagated
by the other methods. Trees propagated as orthotropic rooted cuttings exhibited smaller average stem diameters, shorter stem
heights to the jorquette, and shorter jorquette branches. We concluded that somatic embryo-derived plants demonstrated normal
phenotypes in field conditions and have growth parameters similar to plants propagated by traditional methods. 相似文献