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171.
Garcia-Murillas I Pettitt T Macdonald E Okkenhaug H Georgiev P Trivedi D Hassan B Wakelam M Raghu P 《Neuron》2006,49(4):533-546
An essential step in Drosophila phototransduction is the hydrolysis of phosphatidylinositol 4,5 bisphosphate PI(4,5)P2 by phospholipase Cbeta (PLCbeta) to generate a second messenger that opens the light-activated channels TRP and TRPL. Although the identity of this messenger remains unknown, recent evidence has implicated diacylglycerol kinase (DGK), encoded by rdgA, as a key enzyme that regulates its levels, mediating both amplification and response termination. In this study, we demonstrate that lazaro (laza) encodes a lipid phosphate phosphohydrolase (LPP) that functions during phototransduction. We demonstrate that the synergistic activity of laza and rdgA regulates response termination during phototransduction. Analysis of retinal phospholipids revealed a reduction in phosphatidic acid (PA) levels and an associated reduction in phosphatidylinositol (PI) levels. Together our results demonstrate the contribution of PI depletion to the rdgA phenotype and provide evidence that depletion of PI and its metabolites might be a key signal for TRP channel activation in vivo. 相似文献
172.
Pullakhandam R Nair MK Kasula S Kilari S Thippande TG 《Biochemical and biophysical research communications》2008,374(2):369-372
It is known that the fractional absorption of extrinsic iron from human milk is higher in infants and adults. A low molecular weight milk fraction has been proposed to increase the bioavailability of iron from human milk. Nevertheless, the mechanisms remained elusive. Here in we demonstrate ferric reductase activity (Km 7.73 × 10−6 M) in low molecular weight human milk fraction (10kF, filtrate derived from ultra filtration of milk whey through 10 kDa cutoff membrane), which increased ferric iron solubility and iron uptake in Caco-2 cells. The 10kF fraction was as effective as ascorbic acid (1:20 iron to ascorbic acid) in increasing the ferric iron solubility and uptake in Caco-2 cells. Further, gel filtration chromatography on peptide column led to co-elution of ferric reductase and iron solubilization activities at an apparent molecular mass of <1500 Da. Interestingly, only these fractions containing ferric reductase activity also stimulated the uptake of iron in Caco-2 cells. Thus, it is concluded that human milk possesses ferric reductase activity and is associated with ferric iron solubilization and enhanced absorption. 相似文献
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Krishnamoorthy RR Rao VR Dauphin R Prasanna G Johnson C Yorio T 《Canadian journal of physiology and pharmacology》2008,86(6):380-393
Recent observations suggest that the vasoactive peptide endothelin-1 (ET-1) may be an important contributor to the etiology of glaucoma. ET-1 administration has been shown to produce optic nerve axonal loss and apoptosis of retinal ganglion cells. Ocular ET-1 levels are elevated in aqueous humor in response to elevated intraocular pressure both in glaucoma patients and in animal models of glaucoma; however, the precise mechanisms by which ET-1 mediates glaucomatous optic neuropathy are not clear. Presently we report that ET-1-mediated apoptosis was markedly attenuated in ETB receptor-deficient rats, suggesting a key role for ETB receptors in apoptosis of retinal ganglion cells by ET-1 treatment. Using virally transformed rat retinal ganglion cells (RGC-5 cells), we found that ET-1 (100 nmol/L) treatment produced apoptotic changes in these cells that was determined by flow cytometric analyses, release of mitochondrial cytochrome c to the cytosol, and increased phosphorylation of c-Jun N-terminal kinase. Pretreatment with the ETB-receptor antagonist BQ788 (1 micromol/L) was able to significantly attenuate ET-1-mediated apoptosis in RGC-5 cells. ET-1-mediated apoptotic changes in RGC-5 cells were associated with ETB-receptor activation and were accompanied by a significant upregulation of ETB-receptor expression. These studies suggest that ocular ET-1 acts through ETB receptors to mediate apoptosis of retinal ganglion cells, a key event in glaucoma and related optic neuropathies. 相似文献
175.
Influence of Host Plant Structure and Microclimate on the Abundance and Behavior of a Tephritid Fly 总被引:1,自引:0,他引:1
Microclimate and host plant architecture significantly influence the abundance and behavior of insects. However, most research in this field has focused at the invertebrate assemblage level, with few studies at the single-species level. Using wild Solanum mauritianum plants, we evaluated the influence of plant structure (number of leaves and branches and height of plant) and microclimate (temperature, relative humidity, and light intensity) on the abundance and behavior of a single insect species, the monophagous tephritid fly Bactrocera cacuminata (Hering). Abundance and oviposition behavior were signficantly influenced by the host structure (density of foliage) and associated microclimate. Resting behavior of both sexes was influenced positively by foliage density, while temperature positively influenced the numbers of resting females. The number of ovipositing females was positively influenced by temperature and negatively by relative humidity. Feeding behavior was rare on the host plant, as was mating. The relatively low explanatory power of the measured variables suggests that, in addition to host plant architecture and associated microclimate, other cues (e.g., olfactory or visual) could affect visitation and use of the larval host plant by adult fruit flies. For 12 plants observed at dusk (the time of fly mating), mating pairs were observed on only one tree. Principal component analyses of the plant and microclimate factors associated with these plants revealed that the plant on which mating was observed had specific characteristics (intermediate light intensity, greater height, and greater quantity of fruit) that may have influenced its selection as a mating site. 相似文献
176.
S ummary . The incidence of phosphate-dissolving micro-organisms in two submerged tropical rice soils, and in the rhizosphere of the rice plant growing in one of these soils at different stages of plant development was studied. Large numbers of anaerobic and aerobic phosphate-dissolving bacteria were found in both soils after 11 weeks of submergence. Phosphate-dissolving fungi were found in only one of the soils, a latosolic soil. Both anaerobic and aerobic phosphate-dissolving bacteria were stimulated in the rice rhizosphere. However, the rhizosphere effect was greater in the case of the anaerobic phosphate-dissolving bacteria. The rhizosphere effect was greatest at the transplanting stage of rice plant growth but declined with age of the plants. The greatest decline in R/S ratio occurred between transplanting and initial tillering. 相似文献
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A web accessible resource for investigating cassava phenomics and genomics information: BIOGEN BASE 总被引:1,自引:0,他引:1
Jayakodi M Selvan SG Natesan S Muthurajan R Duraisamy R Ramineni JJ Rathinasamy SA Karuppusamy N Lakshmanan P Chokkappan M 《Bioinformation》2011,6(10):391-392
The goal of our research is to establish a unique portal to bring out the potential outcome of the research in the Casssava crop. The Biogen base for cassava clearly brings out the variations of different traits of the germplasms, maintained at the Tapioca and Castor Research Station, Tamil Nadu Agricultural University. Phenotypic and genotypic variations of the accessions are clearly depicted, for the users to browse and interpret the variations using the microsatellite markers. Database (BIOGEN BASE - CASSAVA) is designed using PHP and MySQL and is equipped with extensive search options. It is more user-friendly and made publicly available, to improve the research and development of cassava by making a wealth of genetics and genomics data available through open, common, and worldwide forum for all individuals interested in the field. AVAILABILITY: The database is available for free at http://www.tnaugenomics.com/biogenbase/casava.php. 相似文献
180.
Prathibha Ranganathan Animesh Agrawal Raghu Bhushan Aravinda K Chavalmane Ravi Kiran Reddy Kalathur Takashi Takahashi Paturu Kondaiah 《BMC genomics》2007,8(1):1-19