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The X-linked subunit of larval serum protein 1 (LSP1-) is shown to lack dosage compensation in six members of the melanogaster species subgroup, viz., Drosophila melanogaster, D. simulans, D. mauritiana, D. erecta, D. yakuba, and D. teissieri, by quantitative filter hybridization and by electrophoretic and autoradiographic analyses of fat body proteins. These results support the hypothesis that there is little selection pressure on the LSP1- gene to acquire dosage compensation.H.W.B. acknowledges a Commonwealth Scholarship. This work was supported by an SRC grant to D.B.R. 相似文献
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Heliothis zea larval mortality time was established for topical applications and per os (feeding) with fungal conidia of Nomuraea rileyi. The 6-to 7-day-old larvae received per os dosages ranging from 6 × 106 to 9 × 109 and a topical dosage of ca. 1 × 109. These spore loads initiated fungal infections in larvae resulting in 1.5–100% accumulated mortality during the 30-day testing periods. The data indicated that regardless of the larval treatment method (topical or per os), or conidial dosage rates, the larval mortality time was never shorter than 5 days post-treatment, nor longer than 22 days. The highest percentage of larval deaths occurred from 7 to 9 days with a maximum mortality at 8 days. 相似文献
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The pea plastocyanin gene in a 3.5 kbp Eco RI fragment of pea nuclear DNA was introduced into tobacco by Agrobacterium-mediated transformation. Regenerated plants contained pea plastocyanin located within the chloroplast thylakoid membrane system. Analysis of seedlings from a self-pollinated transgenic plant containing a single copy of the pea plastocyanin gene indicated that seedlings homozygous for the pea gene contained almost twice as much pea plastocyanin as seedlings hemizygous for the pea gene. Homozygous seedlings contained approximately equal amounts of pea and tobacco plastocyanins. The amount of tobacco plastocyanin in leaves of transgenic plants was unaffected by the expression of the pea plastocyanin gene. The mRNA from the pea gene in tobacco was indistinguishable by northern blotting and S1 nuclease protection from the mRNA found in pea. In both pea and transgenic tobacco, expression of the pea plastocyanin gene was induced by light in leaves but was suppressed in roots. Pea plastocyanin free of contaminating tobacco plastocyanin was purified from transgenic tobacco plants and shown to be indistinguishable from natural pea plastocyanin by N-terminal protein sequencing and 1H NMR spectroscopy. 相似文献
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Fluorimetric determination of febuxostat in dosage forms and in real human plasma via Förster resonance energy transfer 下载免费PDF全文
A rapid, simple, selective and precise fluorimetric method was developed and validated for determination of a selective xanthine oxidase inhibitor; febuxostat (FBX) in pharmaceutical formulations and in human plasma. The proposed method is based on quenching effect of FBX on the fluorescence intensity of terbium (Tb3+) through fluorescence resonance energy transfer (FRET) from Tb3+ to FBX. The formed complex was measured at λex. 320 nm/λem. 490 nm against a reagent blank. Fluorescence intensity of Tb3+ was diminished when FBX was added. A linear relationship between the fluorescence quenching value of the formed complex and the concentration of FBX was investigated. The reaction conditions and the fluorescence spectral properties of the complex have been studied. The linearity range of the developed method was 1.0–16.0 μg/ml. The suggested method was applied successfully for the estimation of FBX in bulk powder, dosage forms and spiked plasma samples with excellent recoveries (96.79–98.89%). In addition, the developed method has been successfully applied for determination of FBX in real plasma samples collected from healthy volunteers with good recoveries (82.06–85.65%). All obtained results of the developed method were statistically analyzed and validated according to ICH (International Conference on Harmonization) guidelines. 相似文献
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G. Gavazzi S. Dolfini D. Allegra P. Castiglioni G. Todesco M. Hoxha 《Molecular & general genetics : MGG》1997,256(3):223-230
Dap (Defective aleurone pigmentation) is the designation for mutations in maize that give rise to a characteristic dappled endosperm phenotype, consisting
of patches of purple tissue, of variable size and shape, on a yellow background. Features shared by all Dap mutants are: dominant expression when they are maternally derived, lack of expression or transmission when they originate
from pollen, failure to recover homozygous Dap genotypes, reduced frequency of Dap seeds in the progeny of outcrosses of Dap/+ females, association of the dappled phenotype with reduction in seed size. The mutants so far tested, six in all, can be
grouped into two classes, one including male-transmissible (MT) isolates not expressed in the endosperm if their contribution
is paternal, and a second class of isolates (NMT) that are permanently lost following paternal transmission. We suggest that
the NMT mutations are on a chromosome that carries an intercalary deletion. Assuming linkage between the mutant and the deletion,
selection against the deficient chromosome during male gametogenesis would account for the failure to recover Dap seeds in the progeny of Dap/+ male parents. We have obtained genetic evidence supporting this hypothesis. This interpretation, however, does not apply
to MT alleles. For these, other mechanisms, such as imprinting and/or dosage effects may be proposed. The mutable pattern
in the endosperm to which all Dap mutants give rise is an intriguing phenotype which remains to be clarified. An unexpected finding is that aleuronic and subaleuronic
cells corresponding to the colourless areas are abnormal in shape and anthocyanin biosynthesis is blocked in these cells.
This finding calls for further investigation in light of a possible connection between flavonoid precursors and cell shape.
Received: 2 January 1997 / Accepted: 26 May 1997 相似文献