全文获取类型
收费全文 | 118篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
现状及发展 | 27篇 |
研究方法 | 15篇 |
综合类 | 75篇 |
自然研究 | 2篇 |
出版年
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2013年 | 1篇 |
2012年 | 6篇 |
2011年 | 9篇 |
2010年 | 1篇 |
2008年 | 10篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 7篇 |
1977年 | 2篇 |
1975年 | 5篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1970年 | 5篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 4篇 |
1966年 | 3篇 |
1965年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有119条查询结果,搜索用时 421 毫秒
81.
82.
Positive interactions among alpine plants increase with stress 总被引:68,自引:0,他引:68
Callaway RM Brooker RW Choler P Kikvidze Z Lortie CJ Michalet R Paolini L Pugnaire FI Newingham B Aschehoug ET Armas C Kikodze D Cook BJ 《Nature》2002,417(6891):844-848
Plants can have positive effects on each other. For example, the accumulation of nutrients, provision of shade, amelioration of disturbance, or protection from herbivores by some species can enhance the performance of neighbouring species. Thus the notion that the distributions and abundances of plant species are independent of other species may be inadequate as a theoretical underpinning for understanding species coexistence and diversity. But there have been no large-scale experiments designed to examine the generality of positive interactions in plant communities and their importance relative to competition. Here we show that the biomass, growth and reproduction of alpine plant species are higher when other plants are nearby. In an experiment conducted in subalpine and alpine plant communities with 115 species in 11 different mountain ranges, we find that competition generally, but not exclusively, dominates interactions at lower elevations where conditions are less physically stressful. In contrast, at high elevations where abiotic stress is high the interactions among plants are predominantly positive. Furthermore, across all high and low sites positive interactions are more important at sites with low temperatures in the early summer, but competition prevails at warmer sites. 相似文献
83.
84.
85.
V. L. Cook A. H. Reese P. D. Wilson G. G. Pinter 《Cellular and molecular life sciences : CMLS》1982,38(1):108-109
Summary Measurements of the glucose to mannitol tracer concentration ratios in renal venous blood and renal lymph of rats supported the hypothesis that reabsorbed glucose may have direct access to renal lymph by passage through the interstitium.Acknowledgment. This research was supported by grant No. AM-17093 of the USPHS. 相似文献
86.
D. E. Cook J. D. Jackson M. R. Past C. M. Lang L. P. Bullock 《Cellular and molecular life sciences : CMLS》1984,40(8):840-841
Summary Both sexes of spontaneously diabetic guinea pigs exhibit hyperinsulinemia (>4-fold normal). This diabetic state is associated with the inhibition of hepatic drug metabolism in males but not females.Supported in part by NIH Grants AM 21282 from the NIAMDD and RR00469 from the DRR 相似文献
87.
88.
89.
90.
It is known that glucose-induced depolarization of pancreatic B-cells is due to reduced membrane K+-permeability and is coupled to an increase in the rate of glycolysis, but there has been no direct evidence linking specific metabolic processes or products to the closing of membrane K+ channels. During patch-clamp studies of proton inhibition of Ca2+-activated K+ channels [GK(Ca)] in B-cells, we identified a second K+-selective channel which is rapidly and reversibly inhibited by ATP applied to the cytoplasmic surface of the membrane. This channel is spontaneously active in excised patches and frequently coexists with GK(Ca) channels yet is insensitive to membrane potential and to intracellular free Ca2+ and pH. Blocking of the channel is ATP-specific and appears not to require metabolism of the ATP. This ATP-sensitive K+ channel [GK(ATP)] may be a link between metabolism and membrane K+-permeability in pancreatic B-cells. 相似文献