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71.
Fourteen peptides corresponding to sequences of all the exposed and some of the transmembrane protein regions of porin A from the outer membrane ofNeisseria meningitidis strain B:15:P1.7,16 were synthesized. Mice of various lines were immunized with the free peptides not conjugated with any protein carrier. It was shown that the majority of the peptides possess immunogenic properties. Two peptides were identified binding to antibodies present in the serum of mice after meningitis. Protective properties of a number of the synthesized peptides were studied, and three peptide sequences inducing mice protection to an experimental infection withN. meningitidis were identified.  相似文献   
72.
The thermotolerant, ethanol-producing yeast strain Kluyveromyces marxianus IMB3 was grown at 45°C on media containing 2, 4 and 6 % (w/v) pulverized barley straw and supplemented with 2% (v/v) cellulase. Maximum ethanol concentrations produced were 2, 3 and 3.6g/l, respectively. When the pulverized straw was replaced by NaOH pretreated straw (at 2, 4 and 6% (w/v); based on original untreated straw), ethanol concentrations increased to maxima of 3.9, 8, and 12g/l, respectively. The ethanol yields amount to 20g ethanol from 100g of straw.  相似文献   
73.
74.
Evolutionary relatedness of some primate models of Plasmodium   总被引:1,自引:0,他引:1  
Primate--and, specifically, monkey--malaria infections are commonly used for understanding the pathology of and immune response to the human disease because they are thought to resemble most closely the host-parasite relationship found in humans. Plasmodium cynomolgi is used extensively as a model for the human parasite, P. vivax, and P. knowlesi is used primarily as a model for the development of erythrocytic-stage vaccines. Both of these simian parasites can naturally infect man, resulting in mildly symptomatic episodes of the disease. The phylogenetic relationship between these two simian parasites and previously characterized Plasmodium species, including P. vivax, was examined by comparison of the asexually expressed small- subunit ribosomal RNA genes. Our analysis confirmed that P. vivax is most closely related to P. cynomolgi and that it remains an appropriate model of the human pathogen. Furthermore, with P. knowlesi and P. fragile, these two species form a group of closely related species, distant from other Plasmodium species. What is considered to be the most ancient of the human malaria pathogens, P. malariae, was also included in the analysis and does not group at all with other simian or human parasites.   相似文献   
75.
Sequence divergence in the internal transcribed spacer region 1 (ITS-1) of the ribosomal DNA locus was assessed in subspecies of the coastal North American tiger beetle, Cicindela dorsalis. The spacer region was amplified using the polymerase chain reaction and cloned for sequencing. Of a total of 50 clones obtained from 12 specimens, 42 clones were different in at least one nucleotide position. In a parsimony analysis of these sequences, the main phylogenetic distinction was found to separate sequences from the Gulf of Mexico and the Atlantic Ocean. Within these two assemblages phylogenetic resolution was low, and the variation within individuals was almost as high as the variation within the entire lineage. The pattern of sequence variation suggests the existence of two forms of the ITS-1 that are maintained on different chromosomes. Polymorphisms of limited geographical distribution could be detected, and 41 additional clones were partly sequenced, to assess the geographic distribution of these polymorphisms in more detail. In a population aggregation analysis, the geographic pattern of ITS-1 distribution was basically congruent with that obtained in earlier studies from mitochondrial DNA in the same C. dorsalis populations.   相似文献   
76.
Hypothesis: For any one time and place a ‘functional signature’ can be derived for a sample of herbaceous vegetation in a way that concisely represents the balance between the different clusters of functional attributes that are present among component species. Methods: We developed a spreadsheet‐based tool for calculating functional signatures within the context of the C‐S‐R system of plant functional types. We used the tool to calculate and compare signatures for specimen British vegetation samples which differed in management regime and location in time. Conclusion: The integrative power of the ‘C‐S‐R signature’ is useful in comparative studies involving widely differing samples. Movements in the signature can be used to indicate degree of resistance, resilience, eutrophication and dereliction. Systems of plant functional types other than C‐S‐R might also be approached in this way. Availability: The tool can be downloaded free of charge from the first author's web pages or from the journal's electronic archive.  相似文献   
77.

Background  

An important component of sexual selection arises because females obtain viability benefits for their offspring from their mate choice. Females choosing extra-pair fertilization generally favor males with exaggerated secondary sexual characters, and extra-pair paternity increases the variance in male reproductive success. Furthermore, females are assumed to benefit from 'good genes' from extra-pair sires. How additive genetic variance in such viability genes is maintained despite strong directional selection remains an evolutionary enigma. We propose that sexual selection is associated with elevated mutation rates, changing the balance between mutation and selection, thereby increasing variance in fitness and hence the benefits to be obtained from good genes sexual selection. Two hypotheses may account for such elevated mutation: (1) Increased sperm production associated with sperm competition may increase mutation rate. (2) Mutator alleles increase mutation rates that are revealed by the expression of condition-dependent secondary sexual characters used by choosy females during their mate choice. M Petrie has independently developed the idea that mutator alleles may account for the maintenance of genetic variation in viability despite strong directional selection.  相似文献   
78.
Mice of various lines were immunized by 11 synthetic peptides that correspond to the sequences of fragments of the OpaB protein from the outer membrane of Neisseria meningitidis involving the known human T-helper epitopes and all the potential mouse T-helper epitopes calculated for the protein. The mice were immunized with the free peptides without their conjugation with a protein carrier. Most of the peptides were found to induce in mice the production of antipeptide antibodies. The mice protection against the experimental infection by a virulent strain of N. meningitidis of the B serotype was studied, and two peptides were shown to exert the most pronounced protective effect.  相似文献   
79.
Fourteen peptides corresponding to sequences of all the exposed and some of the transmembrane protein regions of porin A from the outer membrane of Neisseria meningitidis strain B:15:P1.7,16 were synthesize. Mice of various lines were immunized with the free peptides not conjugated with any protein carrier. It was shown that the majority of the peptides possess immunogenic properties. Two peptides were identified binding to antibodies present in the serum of mice after meningitis. Protective properties of a number of the synthesized peptides were studied, and three peptide sequences inducing mice protection from an experimental infection with N. meningitidis were identified.  相似文献   
80.
The International Crocodilian Genomes Working Group (ICGWG) will sequence and assemble the American alligator (Alligator mississippiensis), saltwater crocodile (Crocodylus porosus) and Indian gharial (Gavialis gangeticus) genomes. The status of these projects and our planned analyses are described.  相似文献   
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