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21.
22.
High level of GUS gene expression driven by pollen-specific promoters in electroporated lily pollen protoplasts 总被引:8,自引:0,他引:8
Gene constructs that contained the -glucuronidase (GUS) gene under the control of a pollen-specific Zm13 promoter from maize and a LAT52 promoter from tomato were introduced by electroporation into pollen protoplasts isolated from bicellular pollen grains of Lilium longiflorum. After 20 h in culture, the pollen protoplasts exhibited the apparent expression of GUS in a fluorometric assay. The GUS activity induced under the control of the Zm13 promoter was over 10 000 times higher than activity in the control (with no DNA or without electroporation). By contrast, the GUS gene was nearly silent in the lily microspore protoplasts and generative cell protoplasts. The GUS activity driven by the Zm13 and LAT52 promoters was also detected by a cytochemical assay. The frequency of blue-staining pollen protoplasts was about 70% in the case of the Zm13 promoter. The efficiency of gene transfer by electroporation was much higher than by particle bombardment. This protoplast-specific electroporation system is suitable for rapid and reliable examination of pollen-specific promoters, being as good as the particle bombardment system. 相似文献
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24.
Summary Microbial degradation of the leaf litter ofShorea robusta Gaertn. was studied for a period of one year. The changes in the major litter constituents like sugar, starch, hemicellulose,
cellulose and lignin were analysed from the litter kept under the nylon bags, at a month's interval. Four major elements phosphorous,
potassium, magnesium and calcium were also assessed monthly from the decaying litter and the soil. The role of microfungi
in mineral cycling and loss of litter substrates have been correlated. 相似文献
25.
Effect of disulfiram on 5-hydroxytryptamine (5-HT) turnover was studied. Treatment with disulfiram caused increases in 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) in rat brain. Under the same condition, activity of brain mitochondrial aldehyde dehydrogenase was reduced, however, supernatant aldehyde dehydrogenase and monoamine oxidase activities remained unchanged. Disulfiram had no effect on synthesis rate of 5-HT, but decreased metabolism of 5-HT. Moreover, disulfiram impaired transport of 5-HIAA from brain tissue. 相似文献
26.
Erich Kessler 《Archives of microbiology》1977,113(1-2):139-141
Five physiological and biochemical characters, which had proved to be valuable for the taxonomy of the genus Chlorella, were studied in the genus Prototheca. There is no hydrogenase activity and no liquefaction of gelatin. Most strains are very acidtolerant (limit of growth at pH 2.0 or 2.5) and very salt-tolerant (limit of growth at 4 or 5% NaCl). Two strains grow well at 38°C. The 16 strains, which were previously assigned to seven taxa, fall into four different groups. Our results tend to support the assumption that Prototheca might be related to Chlorella protothecoides. 相似文献
27.
Summary The effects of diffusion on the dynamics of biochemical oscillators are investigated for general kinetic mechanisms and for a simplified model of glycolysis. When diffusion is sufficiently rapid a population of oscillators relaxes to a globally-synchronized oscillation, but when diffusion of one or more species is slow enough, the synchronized oscillation can be unstable and a nonuniform steady state or an asynchronous oscillation can arise. The significance of these results vis-a-vis models of contact inhibition and zonation patterns is discussed. 相似文献
28.
V. S. Rickeman S. L. Desborough 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1978,52(4):187-190
Summary A modified polyacrylamide gel electrophoresis technique is employed to resolve proteins for use as biochemical gene markers in potato. Dominant, duplicate dominant and complementary gene action are three modes of inheritance that adequately explain the segregation of three respective protein bands in two generations of crossing within diploid Phureja X haploid Tuberosum families.Scientific Journal Seires Article 10,171 of the Minnesota Agricultural Experiment Station 相似文献
29.
Two panels of hybridomas were produced that secreted monoclonal antibodies (MAbs) against recombinant DNA-derived human interleukin 3 and interleukin 4 (rhIL-3 and rhIL-4). From each panel, sensitive immunoradiometric assays (IRMAs) were developed which were capable of detecting the recombinant molecule used as the immunogen but were unable to recognize natural or other recombinant forms of the same cytokine. Subsequent studies using the MAbs from each panel showed that a number of the MAbs appeared only to recognize that particular recombinant molecule used as immunogen, with little or no binding to other recombinant forms of the molecule. By using MAbs that were found to be unrestricted in their recognition for different recombinant forms of the cytokines, it was possible to develop an IRMA for IL-4 that was capable of detecting natural IL-4 as well as all the recombinant forms equally. An IRMA was also developed for IL-3 but was not of equivalent sensitivity in detecting the different recombinant forms of IL-3 used in the study. The recombinant DNA-derived cytokine molecules used to raise the two panels of MAbs contained amino acid substitutions relative to the natural sequences, and these findings indicate that caution should be exercised when using immunoassays to estimate natural sequence molecules if antibodies raised to modified rDNA-derived molecules are used. 相似文献
30.
We describe the binding of [3H]bradykinin to homogenates of guinea pig brain, lung, and ileum. Analysis of [3H]bradykinin binding kinetics in guinea pig brain, lung, and ileum suggests the existence of two binding sites in each tissue. The finding of two binding sites for [3H]bradykinin in ileum, lung, and brain was further supported by Scatchard analysis of equilibrium binding in each tissue. [3H]Bradykinin binds to a high-affinity site in brain, lung, and ileum (KD = 70-200 pM), which constitutes approximately 20% of the bradykinin binding, and to a second, lower-affinity site (0.63-0.95 nM), which constitutes the remaining 80% of binding. Displacement studies with various bradykinin analogues led us to subdivide the high- and lower-affinity sites in each tissue and to suggest the existence of three subtypes of B2 receptors in the guinea pig, which we classify as B2a, B2b, and B2c. Binding of [3H]bradykinin is largely to a B2b receptor subtype, which constitutes the majority of binding in brain, lung, and ileum and represents the lower-affinity site in our binding studies. Receptor subtype B2c constitutes approximately 20% of binding sites in the brain and lung and is equivalent to the high-affinity site in brain and lung. We suggest that a third subtype of B2 receptor (high-affinity site in ileum), B2a, is found only in the ileum. All three subtypes of B2 receptors display a high affinity for bradykinin, whereas they show different affinities for various bradykinin analogues displaying agonist or antagonist activities.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献