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Evolution of overwintering strategies in Eurasian species of the Drosophila obscura species group 总被引:1,自引:0,他引:1
SHIN G. GOTO TAKAO YOSHIDA KATSURA BEPPU MASAHITO T. KIMURA 《Biological journal of the Linnean Society. Linnean Society of London》1999,68(3):429-441
The phylogenetic relationship of Eurasian species of the Drosophila obscura species group remains ambiguous in spite of intensive analyses based on morphology, allozymes and DNA sequences. The present analysis based on sequence data for cytochrome oxidase subunit I (COI) and a-glycerophosphate dehydrogenase (Gpdh) suggests that the phylogenetic position of D. alpina is also ambiguous. These ambiguities have been considered to be attributable to rapid phyletic radiation in this group at an early stage of its evolution. Overwintering strategies are diversified among these species: D. alpina and D. subsihestris pass the winter in pupal diapause, D. bifasciata and D. obscura in reproductive diapause, and D. subobscura and D. guanche without entering diapause. This diversity may also suggest rapid radiation at an early phase of adaptations to temperate climates. On the other hand, adult tolerance of cold was closely related to overwintering strategy and distribution: D. obscura and D. bifasciata with reproductive diapause were very tolerant; D. alpina and D. subsilvestris which pass the winter in pupal diapause were less tolerant; D. subobscura having no diapause was moderately tolerant and D. guanche occurring in the Canary Islands was rather susceptible. Tolerance of high temperature at the preimaginal stages seemed to be also associated with overwintering strategy; i.e. lower in the species with pupal diapause than in those with reproductive diapause or without diapause mechanism. 相似文献
33.
Sweet potato roots of variety Norin No. 1 were cut into discs(319 mm), which were incubated at 2829 for 4 days.At 24-hour intervals, activities of 5-dehydroquinate hydro-lyaseand shikimate-NADP oxidoreductase in the buffer extracts ofdiscs were estimated. The activities of both enzymes were significantlydetected in the fresh root tissues. 5-Dehydroquinate hydro-lyaseactivity per fresh weight increased by three to four times within2 days after slicing, and decreased gradually. Shikimate-NADPoxidoreductase activity at the lst-day incubation period wasfound to be about three times as much as the activity foundin the fresh roots, and it remained for 4 days after slicing.The role of these enzymes in polyphenol biosynthesis in thesliced root tissues is discussed. An attempt to detect the enzymicconversion of dehydroquinic acid to quinic acid is also described.
1This paper constitutes Part 55 of the Phytopathological Chemistryof Sweet Potato with Black Rot.
2Present address: Department of Biology, Tokyo MetropolitanUniversity, Tokyo. Nagoya 相似文献
34.
GILLIS J. HORNER PATRICK J. BAKER RALPH MAC NALLY SHAUN C. CUNNINGHAM JAMES R. THOMSON FIONA HAMILTON† 《Global Change Biology》2009,15(9):2176-2186
River regulation and water extraction have altered the hydrology of rivers resulting in substantial changes to forest structure and the dieback of floodplain forests globally. Forest mortality, due to water extraction, is likely to be exacerbated by climate change-induced droughts. In 1965, a plantation trial was established within a natural floodplain forest to examine the effect of planting density on timber production. We used data from this trial to investigate the effect of initial stand density on the structure and dynamics of Eucalyptus camaldulensis (Dehnh.) forests. Highest density stands (8000 trees ha−1 ) were dominated by many slender trees, mostly<10 cm in diameter, whereas the lowest density stands produced size distributions with a wider range of stem diameters and higher mean and maximum stem diameter. After 1996, the study area experienced a sharp decline in water availability due to a substantial lowering of the water table, reduced flooding frequency, a pronounced rainfall deficit and increased maximum temperatures. The drought coincided with a dramatic increase in mortality in the high-density stands, yet remained little changed in low-density treatments. Our results highlight the importance of initial stand density as a key determinant of the development of forest structure. Early thinning of high-density stands is one component of a broader management approach to mitigate impacts of human-induced drought and water extraction on developing floodplain forests. 相似文献
35.
KIYOTAKA TAKISHITA NATSUKI KAKIZOE TAKAO YOSHIDA TADASHI MARUYAMA 《The Journal of eukaryotic microbiology》2010,57(1):76-86
ABSTRACT. Cold seeps are areas of the seafloor where hydrogen sulfide- and methane-rich fluid seepage occurs, often sustaining chemosynthetic ecosystems. It is well known that both archaea and bacteria oxidize sulfides and methane to produce chemical energy and that several endemic animals use this energy to thrive in cold seeps. On the other hand, there is little knowledge regarding diversity and ecology of microbial eukaryotes in this ecosystem. In this study we isolated environmental RNA and DNA from microbial mats of cold-seep sediment in Sagami Bay, Japan, and retrieved eukaryotic small-subunit ribosomal RNA sequences with polymerase chain reaction methods followed by clone library construction. Most RNA-derived clones obtained were from ciliates, although DNA-derived clones were mainly from the fungus Cryptococcus curvatus , suggesting that ciliates are active in the environment. The ciliate sequences were phylogenetically diverse, and represented eight known class lineages as well as undesignated lineages. Because most ciliates are bacterivorous, it is highly likely that the ciliates for which sequences were recovered play a role in the food web of this ecosystem as grazers of microbial mats. In addition, given that the environment studied is under highly reduced (anoxic) conditions, based on the prokaryotic community structure deduced from T-RFLP profiles, the ciliates detected may be obligatory or facultative anaerobes. 相似文献
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YOSHIO MASUDA CHIKASHI SHIMODA NARAO TAKAO NAOHIKO YANAGISHIMA 《Development, growth & differentiation》1970,12(3):207-215
Effect of yeast (Saccharomyces cerevisiae) sexual hormones on the elongation of etiolated Avena coleoptile segments was studied. The elongation was promoted by a hormone excreted by cells of mating type a, but not by α hormone excreted by cells of α type. The effect of the former was as great as that of 5 mg/1 indole-3-acetic acid in the first hour of application. The optimal concentration of a hormone was 10 units/ml. Its growth promoting effect was greatly inhibited by an antiauxin, 2,4,6-trichlorophenoxyacetic acid. a Hormone increased cell wall extensibility just as auxin does. Testosterone, β-estradiol, progesterone and ergosterol showed very little effect on the elongation of coleoptile segments. 相似文献
39.
Properties of the cell-free extract, prepared from a strainof Thiobacillus thiooxidans by sonic disruption followed byfractionation with centrifugatiori, were investigated with referenceto its sulfite-oxidizing activity. Without the addition of cofactors the particulate fraction(F-P)catalyzed oxidation of sulfite with oxygen or bacterial cytochromec-552 obtained from Pseudomonas stutzeri as electron acceptor.TMPD reduced by ascorbic acid was also oxidized by F-P. Thesoluble fraction(F-S) showed no activity in oxidizing sulfiteand TMPD, but stimulated TMPD oxidation by F-P. Oxygen uptake with either sulfite or TMPD as substrate was inhibitedby KCN, NaN3, CO and c-phenanthroline. CO-Inhibition was reversedby light. Reduction of cytochrome c-552 by sulfite was insensitiveto these agents. Antimycin A markedly inhibited sulfite oxidation with eitheroxygen or cytochrome c-552 as electron acceptor, but was withouteffect on TMPD oxidation. DDC and SAO, both strong inhibitors of sulfur oxidation, didnot affect sulfite and TMPD oxidations. Cytochromes of the a, b and c types were contained in F-P. Thesecytochromes were rapidly reduced when F-P was incubated withsulfite. Cytochrome(s) of the c type was present in F-S, too.
1VI.=References (3)
2Partly supported by a grant from the Ministry of Education
3Present address: Sanyo Women's College, Hatsukaichi, Hiroshima738, Japan
4Present address: Department of Biochemistry, Hiroshima UniversitySchool of Dentistry, Hiroshima 734, Japan (Received May 15, 1970; ) 相似文献
40.
KOJIMA MINEO; MINAMIKAWA TAKAO; HYODO HIROSHI; URITANI IKUZO 《Plant & cell physiology》1969,10(2):471-474
t-Cinnamic acid-2-14C, p-coumaric acid-2-14C and caffeic acid-2-14Cwere administered to discs of sweet potato roots and incorporationof each radioactive compound into chlorogenic acid was compared.The data suggest that chlorogenic acid is synthesized througheither or both of two major pathways, phenylalanine t-cinnamate t-cinnamoyl derivative p-coumaroyl derivative chlorogenicacid and phenylalanine t-cinnamate p-coumarate p-coumaroylderivative chlorogenic acid.
1Part 75 of the phytopathological chemistry of sweet potatowith black rot and injury.
2Present address : Department of Biology, Tokyo MetropolitanUniversity, Setagaya-ku, Tokyo. (Received December 23, 1968; ) 相似文献