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A nomenclature is described for restriction endonucleases, DNA methyltransferases, homing endonucleases and related genes and gene products. It provides explicit categories for the many different Type II enzymes now identified and provides a system for naming the putative genes found by sequence analysis of microbial genomes.  相似文献   
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To reveal the metabolic links between and within pools of pro-atherogenic triglyceride(TG)-rich lipoproteins and anti-atherogenic high density lipoproteins (HDL), the changes in lipoprotein profile at hypertriglyceridemia were analyzed by capillary isotachophoresis. Plasma samples from patients with apoE3/3 phenotype were stained with a fluorescent probe NBD-C6-ceramide and lipoproteins resolved into six H-, one (V+I) and four L-components which belong to HDL, very low and intermediate density (VLDL+IDL) and low density lipoproteins (LDL), respectively. The expected correlation between the relative size of the combined fractions and lipid and apolipoprotein values was obtained confirming the validity of the approach. The new findings were obtained as follows. (1) The fast L-component correlated inversely with HDL-cholesterol (Chol), while intermediate and slow H-components correlated inversely with plasma and LDL-Chol and apoB. (2) The content of intermediate and slow H-components increased within H-pool and decreased relative TG-rich lipoproteins as hypertriglyceridemia rose due to the impairment of triglyceride hydrolysis by lipoprotein lipase within TG-rich particles. (3) A predictive value of the ratios of fast to slow H-components as an indicator of lecithin:cholesterol acyltransferase activity was demonstrated which tended to decrease at hypertriglyceridemia. (4) The L1/L2 ratio may be considered as an indicator of the accumulation of small dense LDL, which is a feature of clinically manifested atherogenic B-pattern. The competition between H(DL) and L(DL) particles for hepatic lipase and significant contribution of apoE to functional deficiency of H(DL) particles at hypertriglyceridemia are suggested.  相似文献   
124.

Background

Streptococcus pneumoniae possesses large zinc metalloproteinases on its surface. To analyse the importance in virulence of three of these metalloproteinases, intranasal challenge of MF1 outbred mice was carried out using a range of infecting doses of wild type and knock-out pneumococcal mutant strains, in order to compare mice survival.

Results

Observation of survival percentages over time and detection of LD50s of knock out mutants in the proteinase genes in comparison to the type 4 TIGR4 wild type strain revealed two major aspects: i) Iga and ZmpB, present in all strains of S. pneumoniae, strongly contribute to virulence in mice; (ii) ZmpC, only present in about 25% of pneumococcal strains, has a lower influence on virulence in mice.

Conclusions

These data suggest Iga, ZmpB and ZmpC as candidate surface proteins responsible for pneumococcal infection and potentially involved in distinct stages of pneumococcal disease.  相似文献   
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Biogeochemistry of methane and methanogenic archaea in permafrost   总被引:1,自引:0,他引:1  
This study summarizes the findings of our research on the genesis of methane, its content and distribution in permafrost horizons of different age and origin. Supported by reliable data from a broad geographical sweep, these findings confirm the presence of methane in permanently frozen fine-grained sediments. In contrast to the omnipresence of carbon dioxide in permafrost, methane-containing horizons (up to 40.0 mL kg(-1)) alternate with strata free of methane. Discrete methane-containing horizons representing over tens of thousands of years are indicative of the absence of methane diffusion through the frozen layers. Along with the isotopic composition of CH(4) carbon (delta(13)C -64 per thousand to -99 per thousand), this confirms its biological origin and points to in situ formation of this biogenic gas. Using (14)C-labeled substrates, the possibility of methane formation within permafrost was experimentally shown, as confirmed by delta(13)C values. Extremely low values (near -99 per thousand) indicate that the process of CH(4) formation is accompanied by the substantial fractionation of carbon isotopes. For the first time, cultures of methane-forming archaea, Methanosarcina mazei strain JL01 VKM B-2370, Methanobacterium sp. strain M2 VKM B-2371 and Methanobacterium sp. strain MK4 VKM B-2440 from permafrost, were isolated and described.  相似文献   
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The skeleton morphology of the azooxanthellate cold-water coral Lophelia pertusa can be strongly influenced by invasive boring sponges that infest corallites in the still living part of the colony. Atypically swollen corallites of live Lophelia pertusa from the Galway Mound (Belgica Carbonate Mound Province, Porcupine Seabight, NE Atlantic), heavily excavated by boring organisms, have been examined with a wide range of non-destructive and destructive methods: micro-computed tomography, macro- and microscopic observations of the outer coral skeleton, longitudinal and transversal thin sections and SEM analyses of coral skeleton casts. As a result, three excavating sponge species have been distinguished within the coral skeleton: Alectona millari, Spiroxya heteroclita and Aka infesta. Furthermore, four main coral/sponge growth stages have been recognised: (1) cylindrical juvenile corallite/no sponge cavities; (2) flared juvenile corallite/linear sponge cavities (if present); (3) slightly swollen adult corallites/chambered oval sponge cavities; (4) very swollen adult corallites/widespread cavities. The inferred correlation between corallite morphology and boring sponge infestation has been detected in micro-computed tomography (micro-CT) images and confirmed in sponge trace casts and peculiar features of coral skeleton microstructure. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users.  相似文献   
127.
Biochemistry (Moscow) - The maintenance of an uneven distribution of Na+ and K+ ions between the cytoplasm and extracellular medium is the basis for the functioning of any animal cell. Changes in...  相似文献   
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One of the most important challenges in agriculture is to determine the effectiveness and environmental impact of certain farming practices. The aim of present study was to determine and compare the taxonomic composition of the microbiomes established in soil following long-term exposure (14 years) to a conventional and organic farming systems (CFS and OFS accordingly). Soil from unclared forest next to the fields was used as a control. The analysis was based on RT-PCR and pyrosequencing of 16S rRNA genes of bacteria and archaea. The number of bacteria was significantly lower in CFS than in OFS and woodland. The highest amount of archaea was detected in woodland, whereas the amounts in CFS and OFS were lower and similar. The most common phyla in the soil microbial communities analyzed were Proteobacteria (57.9%), Acidobacteria (16.1%), Actinobacteria (7.9%), Verrucomicrobia (2.0%), Bacteroidetes (2.7%) and Firmicutes (4.8%). Woodland soil differed from croplands in the taxonomic composition of microbial phyla. Croplands were enriched with Proteobacteria (mainly the genus Pseudomonas), while Acidobacteria were detected almost exclusively in woodland soil. The most pronounced differences between the CFS and OFS microbiomes were found within the genus Pseudomonas, which significantly (p<0,05) increased its number in CFS soil compared to OFS. Other differences in microbiomes of cropping systems concerned minor taxa. A higher relative abundance of bacteria belonging to the families Oxalobacteriaceae, Koribacteriaceae, Nakamurellaceae and genera Ralstonia, Paenibacillus and Pedobacter was found in CFS as compared with OFS. On the other hand, microbiomes of OFS were enriched with proteobacteria of the family Comamonadaceae (genera Hylemonella) and Hyphomicrobiaceae, actinobacteria from the family Micrococcaceae, and bacteria of the genera Geobacter, Methylotenera, Rhizobium (mainly Rhizobium leguminosarum) and Clostridium. Thus, the fields under OFS and CFS did not differ greatly for the composition of the microbiome. These results, which were also confirmed by cluster analysis, indicated that microbial communities in the field soil do not necessarily differ largely between conventional and organic farming systems.  相似文献   
130.
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