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61.
K. Satyanarayana J. H. Yu G. Bhaskaran K. H. Dahm R. Meola 《Entomologia Experimentalis et Applicata》1991,59(2):135-143
At eclosion, the ovaries of female Corn earworm Heliothis zea do not contain mature eggs. Virgin-unfed females produced approximately 400 mature eggs in 8 days; mating or feeding doubled this number, and mating plus feeding more than tripled it. Females allatectomized or decapitated at day O matured few eggs. Egg production was restored by implantation of active corpora allata (CA) or by treatment with the juvenile hormone (JH) analogue methoprene at day 0. 20-Hydroxyecdysone, on the other hand, had no effect. Females in which the CA had been denervated or in which the median neurosecretory cells of the brain had been ablated at day O produced fewer eggs than sham-operated animals. These results indicate that egg maturation is controlled by JH and that continuous input from the brain is required for sustained CA activity for maintaining a high rates of egg maturation.The rate of JH biosynthesis by CA in vitro was determined with a radiochemical assay. The major hormones produced were JH-II and JH-III with small quantities of JH-I. The rates of JH synthesis were similar in all experimental groups which may indicate that the in vitro rate of JH synthesis does not reflect the actual state of CA activity in the female. 相似文献
62.
Physiological changes in cultured sorghum cells in response to induced water stress : I. Free proline 总被引:7,自引:2,他引:5
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Ten varieties of Sorghum bicolor (L.) Moench were grown as callus cultures under conditions of water stress, which was induced by addition of polyethylene glycol (molecular weight 8000) in the medium. Growth and free proline were estimated in the control and water-stressed cultures. In all varieties, proline levels were low in the absence of water stress and the levels increased in response to water stress. However, the magnitude of these increases were not correlated with stress tolerance of the individual varieties in culture. Thus increase in proline seems to be an incidental consequence of stress in vitro and not an adaptive response to combat water stress in sorghum. 相似文献
63.
Screening for drought tolerance in Sorghum using cell culture 总被引:4,自引:0,他引:4
R. H. Smith S. Bhaskaran F. R. Miller 《In vitro cellular & developmental biology. Plant》1985,21(10):541-545
Summary Callus growth from 10 cultivars ofSorghum bicolor (L.) Moench was measured with increasing levels of polyethylene glycol (PEG) as an osmoticum in the medium to determine whether
differences among these cultivars at the cellular level in response to osmotic stress existed. These cellular ratings were
compared to field ratings from the 10 tolerant-to-susceptible cultivars when grown under drought conditions to determine whether
cellular ratings corresponded to differences in drought tolerance at the plant level. Callus cultures were grown on Murashige
and Skoog inorganic salt formulation plus vitamins, 2,4-dichlorophenoxyacetic acid (2,4-D), kinetin and sucrose, supplemented
with 0 to 25% (wt/vol) PEG corresponding to −0.2 to −1.62 MPa osmotic potential. Results suggest that PEG-induced osmotic
stress on callus cultures can be used to screen sorghum cultivars for potential early field (preflowering) drought tolerance.
This implies that at least a component of the early field drought tolerance in sorghum may have a cellular basis.
This study was supported by U.S. Agency for International Development Grant AID/DSAN/XII/G-0149, and USDA Competitive Grants
Program. 相似文献
64.
65.
The structure of postsynaptic densities isolated from dog cerebral cortex: I. overall morphology and protein composition 总被引:38,自引:15,他引:23
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A postsynaptic density (PSD) fraction, including some adherent subsynaptic web material, has been isolated from dog cerebral cortex by a short-procedure modification of methods of Davis and Bloom (21, 22) and Cotman and Taylor (20), using Triton X-100. The fraction has been visualized by thin-section, replica, and negative (phosphotungstic acid) staining electron microscopy and its proteins separated by high-resoltuion SDS gel electrophoresis. Morphologically, the preparation seems to be quite pure, with very little membrane contamination. The density is composed of protein, no nuclei acids, and very little phospholipids being detectable. The fraction had no ATPase or GTPase activity, but it did have a very small amount of cytochrome c oxidase activity (of a specific activity less than 0.5 percent that of a mitochondrial fraction) and a small amount of 5'- nucleotidase activity (of a specific activity between 6 and 7 percent that of a synaptic membrane fraction). Electron micrographs reveal cup-shaped structures approximately 400nm long and approximately 40nm wide, made up of apparent particles 13-28nm in diameter. However, en face views, and particularly micrographs of replicas and PTA-stained preparations, reveal a disk-shaped structure, outside diameter approximately 400 nm, in which filaments are seen to extend from the central part of the density. High resolution gel electrophoresis studies indicated some 15 major proteins and perhaps 10 or more minor ones; the predominant protein had a mol wt of 51,000, followed by ones at 45,000, 40,000, 31,000, 26,000, and several at 100,000. A comparison by gel electrophoresis of density fraction proteins with those of a lysed synaptosomal membrane fraction containing some adherent densities indicated some comigrating proteins, but the major membrane fraction protein, mol wt 52,000, was not found in the density fraction. Antibodies raised against the density fraction reacted with a preparation of solubilized synaptic membrane proteins. By both these criteria, it was considered that the density and the synaptic membrane have some proteins in common. By separately mixing (125)I-labeled myelin, synaptic vesicle, and mitochondrial fraction proteins with synaptosomes, and then isolating the density fraction from the mixture, it was concluded that a major 26,000 mol wt density fraction protein was common to both mitochondria and density, that none of the proteins of the density were contaminants from the mitochondrial fraction, that a minor approximately 150,000 band was a contaminant from the synaptic vesicle fraction, and that the moderately staining PSD fraction protein of 17,000 mol wt band was the result of contamination by the major basic protein of myelin. On the basis of the marker enzymatic assays and the mixing experiments, it is considered that the density fraction is moderately pure biochemically, and that its protein composition, aside from a few exceptions noted above, reflects its in situ character. 相似文献
66.
The structure of postsynaptic densities isolated from dog cerebral cortex: II. characterization and arrangement of some of the major proteins within the structure 总被引:15,自引:0,他引:15
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An attempt was made to identify some of the proteins of the postsynaptic density (PSD) fraction isolated from dog cerebral cortex. The major protein has been tentatively labeled "neurofilament" protein, on the basis of its 51,000 mol wt correspondence to a protein found in neurofilament preparations. Other proteins are akin to some dog myofibrillar proteins, on the basis if immunological crossreaction and equal sodium dodecyl sulfate (SDS)-gel electrophoretic mobilities. While a protein similar to dog muscle myosin is not present in the PSD fraction, a major protein present is actin, as evident from reactivity with antiactin serum, from SDS-gel mobility, and from amino acid composition. Only very little tubulin may be present in the PSD fraction, as determined by gel electrophoresis. Various treatments of the PSD fraction were attempted in order to extract some proteins, as revealed by gel electrophoresis, and to observe the structural changes of the PSD fraction residue after extraction of these proteins. The PSD is remarkably resistant to various extraction conditions, with only 4 M guanidine being found to extract most of the proteins, except the 51,000 mol wt protein. Disulfide reducing agents such as dithiothreitol (DTT), blocking agents such as p-chloromercuribenzoate (PCMB) (both in the presence of deoxycholate [DOC]), a Ca++ extractor, ethylene glycol-bis (beta- aminoethyl ether) N,N,N',N'-tetraacetate (EGTA), and guanidine caused an opening up of the native dense PSD structure, revealing approximately 10-nm filaments, presumably consisting of "neurofilament" protein. Both DTT-DOC and PCMB-DOC removed chiefly actin but also some other proteins. EGTA, in greatly opening up the structure, as observed in the electron microscope, revealed both 10-nm and 3- to 5-nm filaments; the later could be composed of actin, since actin was still in the residue after the treatment. EGTA removed a major 18,000 mol wt component and two minor proteins of 68,000 and 73,000 mol wt. Based on the morphological and biochemical evidence, a picture is presented of the PSD as a structure partly made up of 10-nm and 3- to 5-nm filaments, held together through Ca++ interaction and by bonds amendable to breakage by sulfhydrylblocking and disulfide-reducing reagents; either removal of Ca++ and/or rupture of these disulfide bonds opens up the structure. On the basis of the existence of filamentous proteins and the appearance of the PSD after certain treatments as a closed or open structure, a theory is presented with envisages the PSD to function as a modulator in the conduction of the nerve impulse, by movements of its protein relative. 相似文献
67.
68.
Natarajan Bhaskaran Aaron Weinberg Pushpa Pandiyan 《Journal of visualized experiments : JoVE》2015,(96)
Oropharyngeal Candidiasis (OPC) disease is caused not only due to the lack of host immune resistance, but also the absence of appropriate regulation of infection-induced immunopathology. Although Th17 cells are implicated in antifungal defense, their role in immunopathology is unclear. This study presents a method for establishing oral Th17 immunopathology associated with oral candidal infection in immunodeficient mice. The method is based on reconstituting lymphopenic mice with in vitro cultured Th17 cells, followed by oral infection with Candida albicans (C. albicans). Results show that unrestrained Th17 cells result in inflammation and pathology, and is associated with several measurable read-outs including weight loss, pro-inflammatory cytokine production, tongue histopathology and mortality, showing that this model may be valuable in studying OPC immunopathology. Adoptive transfer of regulatory cells (Tregs) controls and reduces the inflammatory response, showing that this model can be used to test new strategies to counteract oral inflammation. This model may also be applicable in studying oral Th17 immunopathology in general in the context of other oral diseases. 相似文献
69.
70.
Tiana Baqueiro Momtchilo Russo Virgínia MG Silva Thayna Meirelles Pablo RS Oliveira Eliane Gomes Renato Barboza Ana T Cerqueira-Lima Camila A Figueiredo Lain Pontes-de-Carvalho Neuza M Alcantara-Neves 《Respiratory research》2010,11(1):51