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排序方式: 共有292条查询结果,搜索用时 15 毫秒
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T. E. Osmond 《BMJ (Clinical research ed.)》1944,1(4331):51-52
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Luttge Ulrich; Osmond C. Barry; Ball Erika; Brinckmann Enno; Kinze Gabriele 《Plant & cell physiology》1972,13(3):505-514
Bisulfite compounds are shown to be nonspecific inhibitors ofphotosynthetic processes and of ion transport in green tissues.CO2 fixation and light-dependent transient changes in externalpH are inhibited about 50% by 5x104 M glyoxal-Na-bisulfite.Chloride uptake in the light and in the dark is inhibited tothe same extent at this concentration. At 5x103 M theinhibitor reduces ATP levels in the light and in the dark, andeffects on glycolate oxidase and PEP carboxylase are observed.The extent of inhibition is dependent on time of treatment withglyoxal-Na-bisulfite and freshly prepared NaHSO3 is equallyas effective as the addition compound. Possible explanations of the bisulfite effects and the relationshipsto SO2 effects on photosynthesis are discussed. (Received September 1, 1971; ) 相似文献
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Lei Lv Yang Liu Helen L. Osmond Andrew Cockburn Loeske E. B. Kruuk 《Global Change Biology》2020,26(2):443-457
Climate warming has been shown to affect the timing of the onset of breeding of many bird species across the world. However, for multi‐brooded species, climate may also affect the timing of the end of the breeding season, and hence also its duration, and these effects may have consequences for fitness. We used 28 years of field data to investigate the links between climate, timing of breeding, and breeding success in a cooperatively breeding passerine, the superb fairy‐wren (Malurus cyaneus). This multi‐brooded species from southeastern Australia has a long breeding season and high variation in phenology between individuals. By applying a “sliding window” approach, we found that higher minimum temperatures in early spring resulted in an earlier start and a longer duration of breeding, whereas less rainfall and more heatwaves (days > 29°C) in late summer resulted in an earlier end and a shorter duration of breeding. Using a hurdle model analysis, we found that earlier start dates did not predict whether or not females produced any young in a season. However, for successful females who produced at least one young, earlier start dates were associated with higher numbers of young produced in a season. Earlier end dates were associated with a higher probability of producing at least one young, presumably because unsuccessful females kept trying when others had ceased. Despite larger scale trends in climate, climate variables in the windows relevant to this species’ phenology did not change across years, and there were no temporal trends in phenology during our study period. Our results illustrate a scenario in which higher temperatures advanced both start and end dates of individuals’ breeding seasons, but did not generate an overall temporal shift in breeding times. They also suggest that the complexity of selection pressures on breeding phenology in multi‐brooded species may have been underestimated. 相似文献
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Hanna Alastalo Mikaela B. von Bonsdorff Katri R?ikk?nen Anu-Katriina Pesonen Clive Osmond David J. P. Barker Kati Heinonen Eero Kajantie Johan G. Eriksson 《PloS one》2013,8(7)
Background
Severe stress experienced in early life may have long-term effects on adult physiological and psychological health and well-being. We studied physical and psychosocial functioning in late adulthood in subjects separated temporarily from their parents in childhood during World War II.Methods
The 1803 participants belong to the Helsinki Birth Cohort Study, born 1934–44. Of them, 267 (14.8%) had been evacuated abroad in childhood during WWII and the remaining subjects served as controls. Physical and psychosocial functioning was assessed with the Short Form 36 scale (SF-36) between 2001 and 2004. A test for trends was based on linear regression. All analyses were adjusted for age at clinical examination, social class in childhood and adulthood, smoking, alcohol intake, physical activity, body mass index, cardiovascular disease and diabetes.Results
Physical functioning in late adulthood was lower among the separated men compared to non-separated men (b = −0.40, 95% confidence interval [95% CI]: −0.71 to −0.08). Those men separated in school age (>7 years) and who were separated for a duration over 2 years had the highest risk for lower physical functioning (b = −0.89, 95% CI: −1.58 to −0.20) and (b = −0.65, 95% CI: −1.25 to −0.05), respectively). Men separated for a duration over 2 years also had lower psychosocial functioning (b = −0.70, 95% CI: −1.35 to −0.06). These differences in physical and psychosocial functioning were not observed among women.Conclusion
Early life stress may increase the risk for impaired physical functioning in late adulthood among men. Timing and duration of the separation influenced the physical and psychosocial functioning in late adulthood. 相似文献10.
LYMPHOCYTE POPULATIONS IN MOUSE BONE MARROW: QUANTITATIVE KINETIC STUDIES IN YOUNG, PUBERTAL AND ADULT C3H MICE 总被引:6,自引:0,他引:6
Continuous 3H-thymidine infusion was used to characterize two kinetic subpopula-tions of small lymphocytes in mouse bone marrow during normal growth and development. Young (4 wk), pubertal (8 wk) and mature (16 wk) C3H mice were infused subcutaneously with 3H-thymidine for periods up to 10 days. Femoral marrow was then examined in radioautographic smears. During the first 3 days the proportion of marrow small lymphocytes labelled by 3H-thymidine showed a rapid exponential increase to 93%, 81% and 72% in 4 wk, 8 wk and 16 wk mice respectively. The rate of appearance of labelled small lymphocytes then declined markedly but remained higher in younger than in older animals. The labelling curves were found to represent the summation of two exponential curves from which the proportions and renewal rate of corresponding cell populations were calculated. Most marrow small lymphocytes comprised a rapidly renewing population but in mice of increasing age the relative incidence of these cells fell (93-3% at 4 wk; 88-0% at 8 wk; 78-5% at 16 wk) and their half-renewal time (T½) lengthened (14 hr at 4 wk; 18 hr at 8 wk; 24 hr at 16 wk). The remaining small lymphocytes were slowly renewing with mean T½ of 4, 7 and 14 days in 4, 8 and 16 wk mice, respectively. Some heavily labelled small lymphocytes persisted in the marrow up to 10 wk after fourteen daily 3H-thymidine injections in 10–12 wk mice. The numbers of rapidly renewing cells decreased from 604 times 103 to 228 times 103 per mm3 of marrow from 4 wk to 16 wk, respectively, while slowly renewing cells increased from 44 times 103 to 61 times 103 per mm3. The total number of nucleated marrow cells per femur increased from 4 wk to 16 wk but the rapidly renewing small lymphocytes per femur fell in numbers by 36% and in renewal rate by 63%. The results demonstrate a selective change in bone marrow small lymphocytes with age; rapidly renewing cells decline in number and renewal rate while the number of slowly renewing cells increases. The concept of bone marrow as a primary lymphoid organ is discussed. 相似文献