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Nuclear DNAs of three forms of Microtus juldashi--M. carruthersi (group 1) and of three subspecies of polytypic species Alticola macrotis (group 2) were compared. Intensive interpopulational karyotype differentiation was observed in both groups, particularly, for centromeric heterochromatin quantity and localization. As satellite DNAs (satDNAs) were present in C-heterochromatin of the Rodents groups studied, the latter were used as a model for comparison of the satDNAs in the species in statu nascendi. With this view, the nuclear DNAs were studied by means of the neutral CsCl equilibrium centrifugation. In both groups examined, no correlation was found between the presence, the characteristics of the satDNAs and morphological as well as cytogenetic features of the animals. These results are an indirect confirmation of the idea, according to which satDNA does not possibly play significant role in the development of the reproductive isolation and species formation.  相似文献   
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It was shown, that content of dopamine and its metabolites (DOPAC and HVA) are the same in two groups of rats with different time of immobilization in forced swimming test. One group of low active (LA) animals experienced the immobilization more than 300s, other high active (HA) rats for less than 120 s. Ethanol (2 g/kg per oris) increased the level of DA in the striatum and medial prefrontal cortex only in LA rats and besides, the concentration of dopamine after ethanol administration was higher in the n. accumbens of LA rats, than in that of HA rats. The authors suggest that differences in dopamine content between LA and HA rats are connected with different levels of voluntary alcohol consumption. The opportunity to use both groups of HA and LA rats for developing models of pathogenic heterogeneity of alcoholism is discussed.  相似文献   
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Flavonoids (quercetin, rutin) influence ATPase activity and actomyosin superprecipitation. Low concentrations (below 20 mumol/l) of flavonoids were found to cause conformational changes in the myosin structure accompanied by an increase in ATPase activity. At higher concentrations an inhibitory action of flavonoids on both ATPase activity and actomyosin superprecipitation occurred. Conformational changes are likely to be due to flavonoids binding to regulatory site near the active centre of the myosin head. The effect of quercetin was stronger than that of rutin.  相似文献   
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This review is devoted to the molecular and biological properties of natural and artificial Ad-SV40 hybrids. The conditions of adenovirus and SV40 recombinant formations are discussed. The principal one is the ability of the C-terminal portion of the SV40 T-antigen to carry a helper function for growing human adenoviruses in the cultures of simian cells, in which the adenoviruses themselves are not reproduced. The data about the structural and functional organization of the hybrid RNA and proteins, tumor properties of defective and nondefective Ad-SV40 recombinants are provided. A special chapter is devoted to the construction of Ad-SV40 hybrids in vitro. The possibility of using them not only for the investigation of adenoviral properties, but for the super production of different proteins is marked. Alongside the corresponding region of SV40 genome may perform the function of a selection marker for the creation of eucaryotic vectors on the basis of adenoviruses.  相似文献   
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The spatial distributions of the RF power absorbed by plasma electrons in an ion source operating in the helicon mode (ω ci < ω < ω ce < ω pe ) are studied numerically by using a simplified model of an RF plasma source in an external uniform magnetic field. The parameters of the source used in numerical simulations are determined by the necessity of the simultaneous excitation of two types of waves, helicons and Trivelpiece-Gould modes, for which the corresponding transparency diagrams are used. The numerical simulations are carried out for two values of the working gas (helium) pressure and two values of the discharge chamber length under the assumption that symmetric modes are excited. The parameters of the source correspond to those of the injector of the nuclear scanning microprobe operating at the Institute of Applied Physics, National Academy of Sciences of Ukraine. It is assumed that the mechanism of RF power absorption is based on the acceleration of plasma electrons in the field of a Trivelpiece-Gould mode, which is interrupted by pair collisions of plasma electrons with neutral atoms and ions of the working gas. The simulation results show that the total absorbed RF power at a fixed plasma density depends in a resonant manner on the magnetic field. The resonance is found to become smoother with increasing working gas pressure. The distributions of the absorbed RF power in the discharge chamber are presented. The achievable density of the extracted current is estimated using the Bohm criterion.  相似文献   
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The most recent publications on the phylogenetic and functional diversity of thermophilic prokaryotes inhabiting thermal deep-sea environments are reviewed. Along with a general physicochemical characterization of the biotope studied, certain adaptation mechanisms are discussed that are peculiar to the microorganisms inhabiting it. A separate chapter addresses the phylogenetic analysis of deep-sea hydrothermal microbial communities and uncultivated microorganisms recently discovered therein using molecular biological techniques. Physiological groups of thermophilic microorganisms found in deep-sea hydrothermal vents are considered: methanogens, sulfate-, iron-, and sulfur-reducers, aerobic hydrogen-oxidizing prokaryotes, aerobic and anaerobic organotrophs. In most cases, the isolates represent novel taxons.  相似文献   
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Migration of FITC-labeled mouse bone marrow cells into the thymus was measured by flow cytometric analysis 3 hours after intravenous injection of cells into irradiated mice. The percentage of cells reaching the thymus diminished when the dose of injected cells increased. The dependence of the number or labeled cells in the thymus on the dose of injected cells was not linear. Pretreatment of cells with anti-SC-I serum, peanut lectin or H-2 incompatibility antigen abolished thymus migration, while treatment with anti-Thy-I serum, soybean lectin, trypsin or Thy-I-incompatibility antigen diminished cellular migration and treatment with neuraminidase enhanced it. It was concluded that the main type of migrating cells is SC-1+ precursors of T-lymphocytes. Penetration of these cells through the blood-thymus barrier is based on the recognition of their partly sialized surface glycoprotein receptors by membrane lectins of the blood-thymus barrier cells.  相似文献   
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