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61.
Summary The effect of container porosity on water relations in the substrate and on plant growth was examined. With clay containers
the proportional effect of the wall on water loss varied with season, being responsible for 42 per cent of the total loss
in winter and 25 per cent in summer. Water loss from plastic containers was 55 per cent of that from clay containers in winter,
and 66 per cent in summer. Wall porosity also had a significant effect on water distribution within the container under high
radiation conditions.
Tomato plants grown under three water regimes showed no effect of matric stress in winter, but growth was significantly reduced
for each increase in stress in summer. There was no interaction between container type and water stress.
Non-porous containers gave a higher water-use efficiency and had a lower irrigation requirement than porous ones, their greatest
advantage being under conditions of low transpirational loss and high evaporative loss. 相似文献
62.
63.
Summary A multiple series of alleles of the gene MZ exist inSaccharomyces. The members of this series are differentiated from one another by their adaptive response to maltose, turanose, sucrose, melezitose and alpha-methyl glucoside. The more capable members of the series can ferment all five sugars while various multiple alleles are characterized by loss of ability to act on alpha-methyl glucoside, melezitose or sucrose. MZ is linked to the gene MA which controls the production of a specific maltase and to the gene MG which controls the production of a specific alpha-methyl glucosidase. All members of the series of multiple alleles produce the same enzyme showing that the gene and the enzyme are not identical. The enzyme is produced in three different steps, the initial one being a specific reaction of gene with substrate and the final one being a non-specific elicitation of enzyme.This work has been supported by research grants from The National Cancer Institute of the National Institutes of Health, U.S. Public Health Service and Anheuser-Busch, Inc. 相似文献
64.
65.
The effect of light, of 2 wavelengths, and of 3 temperatures on the uptake and evolution of O2 by the antarctic marine diatom, Fragilaria sublinearis, has been examined with mass spectrometry. The responses of this organism to light, in terms of O2 exchange, were qualitatively similar to those recorded by Hoch et al. with the blue-green Anacystis nidulans. In addition, distinctive temperature optima were indicated for O2, production and uptake, which help to explain the psychrophilic character of the diatom. The possibility of varying rates of O2 uptake in the light being associated with photoassimilation of organic substrates has been discussed. 相似文献
67.
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69.
A fluoroenzymatic microdetermination of lactose in tissue culture medium is described. The method is based on the conversion of lactose to galactonic acid by the enzymes galactosidase and galactose dehydrogenase. The resultant reduction of NAD to NADH is measured fluorometrically. Before assaying for lactose the high background fluorescence of tissue culture medium is reduced by deproteinization and adsorption of fluorescent substances with either Florisil or dextran-charcoal. As little as 0.05 nmol of lactose in medium with or without phenol red can be detected after this treatment, whereas for untreated medium the limit of sensitivity of the assay is 1.0 nmol. This method should prove useful for the detection of lactose produced by small numbers of mammary epithelial cells in culture. 相似文献
70.
Hope H. Punnett Mildred L. Kistenmacher Maria A. Toro-Sola Gertrude Kohn 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1973,43(3-4):134-138
Summary Using quinacrine fluorescence and Giemsa banding techniques we have identified an extra chromosome 22 in three non-mongoloid children with similar phenotypes and 47 chromosomes. In one of the children, the long arm of the extra 22 was shorter than usual. This 22q—chrcmcscme was observed in 4 normal family members with 46 chromosomes. In a fourth child, with similar physical findings, the extra G chromosome was shown to be neither a normal 21 nor 22. It must have arisen from a rearrangement in a parental gamete since it was not present in either parent's karyotype.No constellation of clinical findings, in association with an extra G chromosome, is sufficient evidence for the diagnosis of trisomy 22. The positive identification of the extra chromosome must be made using fluorescence and banding.This paper is dedicated to Professor Marcus M. Rhoades on his 70th birthday in grateful recognition of his friendship, help and advice.Supported in part by U.S. Public Health Service Grants HD1313, RR-75 and TI-HD-66 from the National Institutes of Health. A portion of this paper was presented at the annual meeting of the Society for Pediatric Research, Atlantic City, N.J. May 1, 1971. 相似文献