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461.
A significant difference between the maxima of the specific growth rate (μ) and the specific product formation (kp) may indicate a retarded correlation model of biomass (X) and product (P). Therefore phenomenological growth parameters which connect X and P or their derivations (Yp/x, kp) have to take into consideration this kind of lag-time in the same way. 相似文献
462.
Influence of iron,phosphate and methyl viologen on glycerol fermentation of Clostridium butyricum 总被引:2,自引:0,他引:2
The effect of methyl viologen addition, and iron and phosphate limitation on product distribution during glycerol fermentation
of Clostridium butyricum DSM 5431 was investigated in continuous culture. Special attention was paid to the gaseous products H2 and CO2, which were measured on-line. In all three cases, an increased yield of 1,3-propanediol linked to a decreased hydrogen release
was observed, indicating that a higher proportion of electrons was channelled from reduced ferredoxin towards NADH2 production. The specific substrate consumption rates and the specific production rates revealed that this increase in propanediol
yield was not obtained at the expense of glycolysis products but by an increased substrate conversion (overflow metabolism).
The acetate/ butyrate ratio during glycerol fermentation was essentially influenced by the availability of iron. It was substantially
increased when the culture turned from iron excess to iron-limited conditions. Therefore iron limitation proved to be a suitable
means to achieve high 1,3-propanediol yields and to reduce butyrate formation.
Received: 29 August 1995 / Accepted: 20 September 1995 相似文献
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Two monoclonal antibodies, designated 7H5 and 8E11, were produced against glycogen synthase purified from rabbit skeletal muscle. Both antibodies were of the IgG1 (k) isotype. Western blot analysis of extracts of rat and rabbit tissues showed that antibody 7H5 recognized glycogen synthase from skeletal and cardiac muscles, but not from liver. Antibody 8E11 gave similar results but the responses were weaker. Antibody 7H5 also recognized a 69,000 dalton tryptic fragment of glycogen synthase whereas antibody 8E11 did not bind this fragment. Immunocytochemical staining of rabbit skeletal muscle with antibody 7H5 indicated two major sites of glycogen synthase localization. A granular localization present in the cytoplasm and a band-like staining associated with the Z-disk region of the myofibrils. Rabbit cardiac muscle presented a similar pattern though less cytoplasmic staining was apparent. An assay of subcellular fractions for glycogen synthase indicated that the enzyme in cardiac and skeletal muscles is distributed between the soluble (80-90%) and myofibrilar (10-20%) fractions of the tissues. These results provide direct evidence for the presence of glycogen synthase in subcellular fractions other than the soluble fraction of skeletal and cardiac muscles. 相似文献
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C Nicolau H D Klenk K Hildenbrand B Reimann A Reimann H Bauer 《Biophysics of structure and mechanism》1979,5(1):11-23
The fluorescence depolarization of 1,6-diphenyl-hexatriene was used to study the dynamic properties of the hydrophobic regions of the lipid envelopes of ortho- and paramyxoviruses as well as of the Rous sarcoma virus and of the membrane lipids of susceptible and nonsusceptible cells. The systems investigated where active and inactive influenza viruses, and NDV virus acting on chick embryo fibroblasts and Rous sarcoma virus acting on susceptible (C/E) and nonsusceptible (C/B) chicken-cell. Polarization degrees and mean rotational correlation times of DPH embedded in viral lipids were significantly higher than those of DPH in the cell membranes, due to a higher rigidity of the virus envelopes. When suspensions of labelled viruses and unlabelled cells or unlabelled viruses and labelled cells were mixed, a characteristic change of the fluorescence polarization degrees with time was observed. This behaviour was ascribed to label transfer from virus to cell membranes or vice versa. While the rate constants of label transfer from virus to cells and cells to virus were about the same for the penetrating viruses the rate constants of label release from inactive virus to cells were much larger than for the migration in the opposite direction. 相似文献
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