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51.
MASAHISA NAKAMURA AKIRA SUZUKI SHOICHI OKINAGA KIYOSHI ARAI 《Development, growth & differentiation》1984,26(1):11-16
Effect of fructose 2, 6-bisphosphate on 6-phosphofructokinase (ATP: D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) in spermatid extract from rat testes was studied. Fructose 2, 6-bisphosphate stimulated the enzyme greatly by increasing its affinity for fructose 6-phosphate and relieving the inhibition by ATP. Fructose 2, 6-bisphosphate (0.8 μM) was required for 50% activation of 6-phosphofructokinase (PFK). In addition, fructose 2, 6-bisphosphate, AMP and fructose 6-phosphate acted cooperatively to stimulate the activity of PFK. This stimulation may play an important role in the regulation of glycolysis in spermatids of rat testes. 相似文献
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1. Chlorella ellipsoidea was cultured under photo-heterotrophicconditions. Cells showed most favorable growth when 0.2% glucosewas added at the start to the inorganic nutrient medium. 2. Treatment with a mixed solvent, methanol/hexane: 4/3, gavehighly decolorized cells. Molasses alone and pyruvate in combinationwith glucose or with molasses and glucose were effective inobtaining a high yield of chlorophyll and carotenoid pigments. 3. The nitrogen content was lower in bleached cells than innormal cells. Protein yield obtained by the urea soaking methodwas higher with bleached cells than with normal cells. 4. Electron microscopic studies revealed that the outer partof normal cells consists of two layers, an electron-dense innerlayer and an electron-lucent outer layer, whereas, that of bleachedcells consists of only an electron-dense layer. (Received August 28, 1969; ) 相似文献
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OFELIA ANGULO KIYOAKI OKAYAMA TSUKASA NAKAMURA RANDALL YUEN MICHAEL O'MAHONY 《Journal of sensory studies》2009,24(2):258-268
Besides responses to the different stimuli being tested in a paired preference test, responses to identical "placebo" stimuli can be used as a screening tool to identify biased consumers. Those consumers who give preference responses to identical stimuli can be assumed to be biased. Accordingly, only the data from unbiased consumers need to be considered for the different stimuli. The problem with this procedure is that the sample size is reduced. The goal of the present research was to see whether using options associated with purchase intent, elicited a greater number of "No Preference" responses to identical "placebo" stimuli. It was found that they did. The increase was large when the preference options implied exclusivity. In conditions where the preference strength options were not so strong, the frequency of "No Preference" responses dropped accordingly.
A problem with paired preference testing is the tendency of consumers to give false preferences, which produces the seriously misleading overestimation of the proportion of consumers who have preferences for one or other of the products being assessed. The "placebo" condition is an important control for alleviating this problem. The statistical analysis can be improved by finding a protocol that maximizes the proportion of "No Preference" responses in the placebo condition. The key finding here is that using purchase intent questions rather than preference questions may possibly provide a way of achieving this aim. 相似文献
PRACTICAL APPLICATIONS
A problem with paired preference testing is the tendency of consumers to give false preferences, which produces the seriously misleading overestimation of the proportion of consumers who have preferences for one or other of the products being assessed. The "placebo" condition is an important control for alleviating this problem. The statistical analysis can be improved by finding a protocol that maximizes the proportion of "No Preference" responses in the placebo condition. The key finding here is that using purchase intent questions rather than preference questions may possibly provide a way of achieving this aim. 相似文献
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Reproductive biology including mating, adult longevity, fecundity and development of the tachinid fly Zenillia dolosa was investigated for optimizing rearing procedures using Mythimna separata as a host in the laboratory. Females lay microtype eggs containing a first instar larva on food plants of the host and then the eggs must be ingested by the host for parasitization. Mating success was 58.5% with mating duration of 80.7 min. Mating was most successful when day 0–1 females were kept with day 2–4 male flies. Female body size was positively correlated with its fecundity but not with longevity. However, females that survived longer produced more eggs during their lifetime. Parasitoids successfully developed in 4th to 6th instar host larvae. Host instars at the time of parasitoid egg ingestion significantly influenced development time of the immature parasitoid, but did not affect body size of the emerging parasitoid. We suggest that pairing newly emerged females with day 2–4 males should result in higher mating success and using the last instar hosts for parasitization should minimize development time of the parasitoid for rearing. 相似文献
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MASAHISA NAKAMURA IKUO YASUMASU SHOICHI OKINAGA KIYOSHI ARAI 《Development, growth & differentiation》1982,24(3):265-272
Rotenone-sensitive 14 CO2 formation from [14 C]lactate and oxygen consumption by round spermatids were found to be greater at elevated temperatures than at 34°C. More than 96% of the total radioactivity of the metabolized [14 C]lactate was recovered in the released CO2 and the acid soluble fraction of the cells. There was practically no incorporation of [14 C]latctate into the lipid, nucleic acid, and protein fractions. Intracellular level of ATP in spermatids was enhanced in the presence of lactate (20 mM) at 34°C (scrotal temperature), whereas it was decrease at 37°C (body temperature). However, this was reversible when the cells were transferred from the elevated temperature to 34°C. It was also found that oxygen consumption and CO2 production were increased at 34°C by 2, 4-dinitrophenol (DNP), but decreased by oligomycin. On the other hand, oligomycin and DNP had no effect on oxygen consumption and 14 CO2 formation at the elevated temperature.
These findings provide evidence that lactate utilization by spermatids is coupled with oxidative phosphorylation at scrotal temperature, but becomes uncoupled at elevated temperature, although more lactate is consumed. 相似文献
These findings provide evidence that lactate utilization by spermatids is coupled with oxidative phosphorylation at scrotal temperature, but becomes uncoupled at elevated temperature, although more lactate is consumed. 相似文献
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Zaira cinerea (Fallén) is a parasitoid fly (Diptera: Tachinidae) that attacks adult carabid beetles. To better understand mechanisms of population persistence in this species, we examined seasonality of host beetle abundance, the frequency of parasitism, and the timing of fly eclosion. In addition, we evaluated host quality using numbers of larvae or puparia per individual beetle as a measure of quality. The fly parasitized only large carabids (≥15 mm body length); the lengths of fly puparia reached 7.4–10.8 mm during development in beetle abdomens, and larger hosts are likely essential. Of the 18 large carabid species collected in this study, we chose two, Carabus maiyasanus Bates and Leptocarabus procerulus (Bates), because they were large and abundant (87% of total catch). The two carabids had different phonologies; C. maiyasanus was abundant from spring to summer, and its abundance dropped sharply in autumn, while L. procerulus was abundant in autumn and rare from spring to summer except July. Parasitism was observed in all the months from May to November except June, and adult flies eclosed more than once a year (in early summer, late summer, and mid‐autumn), indicating that the species is multivoltine. Host quality of L. procerulus was higher than that of C. maiyasanus. Carabus maiyasanus was mainly used as a host from spring to summer, and L. procerulus was used in autumn. Thus, adult beetles of one or both species are available over most of spring, summer, and autumn, allowing population persistence of this fly species over time. 相似文献