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排序方式: 共有164条查询结果,搜索用时 78 毫秒
91.
K Ia Ogleznev R Kh Ramazanov A N Sovetov Z F Zvereva 《Biulleten' eksperimental'no? biologii i meditsiny》1986,102(7):115-116
The effect of ultrasonic neurosurgical instruments on the functional state of the brain and its individual structures was studied to establish the most adequate and the least traumatic method of brain structures extirpation. Cortical zones were destroyed by ultrasound, thermocoagulated or extirpated. Parallel recordings of evoked potentials to single and paired stimuli were performed in adjacent neocortical areas. It was established that ultrasonic instruments permit the least traumatic extirpation of brain cortical zones. 相似文献
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A. A. Zabelin T. Y. Fufina L. G. Vasilieva V. A. Shkuropatova M. G. Zvereva A. Y. Shkuropatov V. A. Shuvalov 《Biochemistry. Biokhimii?a》2009,74(1):68-74
Methods of photoinduced Fourier transform infrared (FTIR) difference spectroscopy and circular dichroism were employed for studying features of pigment-protein interactions caused by replacement of isoleucine L177 by histidine in the reaction center (RC) of the site-directed mutant I(L177)H of Rhodobacter sphaeroides. A functional state of pigments in the photochemically active cofactor branch was evaluated with the method of photo-accumulation of reduced bacteriopheophytin H A ? . The results are compared with those obtained for wild-type RCs. It was shown that the dimeric nature of the radical cation of the primary electron donor P was preserved in the mutant RCs, with an asymmetric charge distribution between the bacteriochlorophylls PA and PB in the P+ state. However, the dimers P in the wild-type and mutant RCs are not structurally identical due probably to molecular rearrangements of the PA and PB macrocycles and/or alterations in their nearest amino acid environment induced by the mutation. Analysis of the electronic absorption and FTIR difference P+Q?/PQ spectra suggests the 173-ester group of the bacteriochlorophyll PA to be involved in covalent interaction with the I(L177)H RC protein. Incorporation of histidine into the L177 position does not modify the interaction between the primary electron acceptor bacteriochlorophyll BA and the bacteriopheophytin HA. Structural changes are observed in the monomer bacteriochlorophyll BB binding site in the inactive chromophore branch of the mutant RCs. 相似文献
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A.A. Petrenko L.I. Korolenkova D.A. Skvortsov M.D. Fedorova M.U. Skoblov A.V. Baranova M.E. Zvereva M.P. Rubtsova F.L. Kisseljov 《Biochimie》2010
Cervical cancers are characterized by the persistence of human papilloma virus (HPV) genome that is found in tissue samples starting from the early stages of tumor progression. Just like in other tumors, the activation of telomerase was observed in cervical carcinomas, but information about its expression was controversial. The aim of this study is to find possible correlations between the presence of HPV sequences, activity of telomerase and expression of different spliced forms of hTERT RNA in cervical intraepithelial neoplasias (CIN). The results show that HPV DNA is present in 60% of normal tissue adjacent to CIN lesions and up to 84% in CIN samples. Telomerase activity was found in 28% of adjacent normal tissue and in 68% of CIN II–III. hTERT RNA that encodes an active enzyme was present almost in all CIN samples. Variations in levels of telomerase activity are possibly not regulated by the splicing forms of hTERT mRNA with deletions. 相似文献
96.
M Ozkan SG Desai Y Zhang DM Stevenson J Beane EA White ML Guerinot LR Lynd 《Journal of industrial microbiology & biotechnology》2001,27(5):275-280
Characteristics of 13 newly isolated thermophilic, anaerobic, and cellulolytic strains were compared with previously described
strains of Clostridium thermocellum: ATCC 27405 and JW20 (ATCC 31549). Colony morphology, antibiotic sensitivity, fermentation end-products, and cellulose degradation
were documented. All 13 strains were sensitive to erythromycin (5 μg/ml) and chloramphenicol (25 μg/ml), and all strains but
one were sensitive to kanamycin (20 μg/ml). Polymerase chain reaction (PCR) amplification using primers based on gene sequences
from C. thermocellum ATCC 27405 was successful for all 13 strains in the case of the hydrogenase gene and 11 strains in the case of phosphotransacetylase/acetate
kinase genes. Ten strains amplified a product of the expected size with primers developed to be specific for C. thermocellum 16SrRNA primers. Two of the 13 strains did not amplify any product with the PCR primers designed for the phosphotransacetylase/acetate
kinase and 16SrRNA primers. A MboI-like GATC- recognizing restriction activity was present in all of the five strains examined. The results of this study have
several positive implications with respect to future development of a transformation system for cellulolytic thermophiles.
Journal of Industrial Microbiology & Biotechnology (2001) 27, 275–280.
Received 12 September 2000/ Accepted in revised form 20 November 2000 相似文献
97.
We have studied for the first time the taxonomic composition of filamentous fungi associated with the bivalve mollusks Crenomytilus grayanus (Bunker, 1853) and Modiolus modiolus (Linnaeus, 1758), collected in polluted biotopes of Ussuriiskii Bay (Peter the Great Bay, Sea of Japan). One hundred fifty-five
strains of higher fungi were isolated, and 35 species of filamentous fungi were identified. Out of these, 28 species were
anamorphous fungi of the genera Aspergillus (12), Penicillium (10), Acremonium (1), Alternaria (1), Aureobasidium (1), and Cladosporium (3) (Deuteromycota), and 7 were species of the genera Chaetomium (6) and Myxotrichum (1) (Ascomycota). Twenty-four species of filamentous fungi were isolated from the internal organs of C. grayanus: 8 from the muscles, 8 from the hepatopancreas, 6 from the female gonads, 4 from the mantle, 3 from the kidneys and male
gonads, and 1 from the gills. Twenty-one species of filamentous fungi were isolated from the internal organs of Modiolus modiolus: 10 from the muscles, 6 from the hepatopancreas, 5 from the female gonads, 3 from the kidneys, 3 from the mantle, and 1 from
the gills. The bulk of the isolated species of the genera Aspergillus, Penicillium, Cladosporium, and Chaetomium were pathogenic and toxigenic fungi. 相似文献
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The process of cell generalization of lymphatic leukemia transplanted clone of AKR mice was studied by the routine and differential methods of metaphase chromosome staining. In 99.5% cases, the cells have an additional small chromosome specific for this type of leukemia, the chromosome being comparable in size with 18-19 pairs of chromosomes of mouse karyotype. Generalization process within 7 days' experiment (from the moment of transplantation up to the moment of animals' death from lymphatic leukemia) appeared to be slower in thymus and bone marrow of AKR mice than in spleen, lymphatic nodes and liver of the same animals with nearly the same generalization rate. A change in the frequency of marked leukemic cells in various organs at different time intervals after transplantation of lymphatic leukemia correlated with intensive cell division of an undulating character in all organs. The data obtained show that hyperdiploid cells carrying the specific additional small chromosome are responsible for the generalization process, this chromosome being also present in spontaneous strain of AKR mice, from which this clone was obtained. 相似文献