全文获取类型
收费全文 | 134篇 |
免费 | 3篇 |
出版年
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2003年 | 2篇 |
1999年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1994年 | 3篇 |
1992年 | 4篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1962年 | 1篇 |
1958年 | 7篇 |
1957年 | 1篇 |
1956年 | 4篇 |
1955年 | 1篇 |
1954年 | 7篇 |
1953年 | 4篇 |
1952年 | 3篇 |
1951年 | 10篇 |
1950年 | 3篇 |
1949年 | 1篇 |
1935年 | 1篇 |
1933年 | 2篇 |
1932年 | 1篇 |
1930年 | 2篇 |
1929年 | 1篇 |
1927年 | 1篇 |
1921年 | 1篇 |
排序方式: 共有137条查询结果,搜索用时 625 毫秒
71.
72.
73.
74.
75.
76.
Degeneration of the intervertebral disc 总被引:3,自引:0,他引:3
The intervertebral disc is a cartilaginous structure that resembles articular cartilage in its biochemistry, but morphologically
it is clearly different. It shows degenerative and ageing changes earlier than does any other connective tissue in the body.
It is believed to be important clinically because there is an association of disc degeneration with back pain. Current treatments
are predominantly conservative or, less commonly, surgical; in many cases there is no clear diagnosis and therapy is considered
inadequate. New developments, such as genetic and biological approaches, may allow better diagnosis and treatments in the
future. 相似文献
77.
Adam R Meir Jeremy CT Fairbank Deborah A Jones Donal S McNally Jill PG Urban 《Scoliosis》2007,2(1):1-16
Background
Loads acting on scoliotic spines are thought to be asymmetric and involved in progression of the scoliotic deformity; abnormal loading patterns lead to changes in bone and disc cell activity and hence to vertebral body and disc wedging. At present however there are no direct measurements of intradiscal stresses or pressures in scoliotic spines. The aim of this study was to obtain quantitative measurements of the intradiscal stress environment in scoliotic intervertebral discs and to determine if loads acting across the scoliotic spine are asymmetric. We performed in vivo measurements of stresses across the intervertebral disc in patients with scoliosis, both parallel (termed horizontal) and perpendicular (termed vertical) to the end plate, using a side mounted pressure transducer (stress profilometry)Methods
Stress profilometry was used to measure horizontal and vertical stresses at 5 mm intervals across 25 intervertebral discs of 7 scoliotic patients during anterior reconstructive surgery. A state of hydrostatic pressure was defined by identical horizontal and vertical stresses for at least two consecutive readings. Results were compared with similar stress profiles measured during surgery across 10 discs of 4 spines with no lateral curvature and with data from the literature.Results
Profiles across scoliotic discs were very different from those of normal, young, healthy discs of equivalent age previously presented in the literature. Hydrostatic pressure regions were only seen in 14/25 discs, extended only over a short distance. Non-scoliotic discs of equivalent age would be expected to show large centrally placed hydrostatic nuclear regions in all discs. Mean pressures were significantly greater (0.25 MPa) than those measured in other anaesthetised patients (<0.07 MPa). A stress peak was seen in the concave annulus in 13/25 discs. Stresses in the concave annulus were greater than in the convex annulus indicating asymmetric loading in these anaesthetised, recumbent patients.Conclusion
Intradiscal pressures and stresses in scoliotic discs are abnormal, asymmetrical and high in magnitude even in the absence of significant applied muscle loading. The origin of these abnormal stresses is unclear. 相似文献78.
Nitrogen Deficiency Slows Leaf Development and Delays Flowering in Narrow-leafed Lupin 总被引:1,自引:0,他引:1
Effects of nitrogen (N) supply on leaf and flower developmentinLupinus angustifolius L. cv Merrit were examined in a temperature-controlledglasshouse. Low N supply (0.05 or 0.4 mM N) had little effecton leaf initiation but slowed leaf emergence on the main stemcompared with plants receiving high N supply (6.0 or 6.4 mMN), or with symbiotic N2-fixation. Plants experiencing transientN deficiency had slower leaf emergence than plants with a continuoussupply of 6.4 mM N. Nitrogen supply did not affect the timeof floral initiation, which occurred within 4 weeks of sowing,by which time nine to ten leaves had emerged. However, the floweringof low-N plants was delayed by 68 to 220 °C d (i.e. 414d) even though they had fewer leaves. The effect of N deficiencyon flowering time was largely a result of slower leaf emergence. Lupinus angustifolius L.; nitrogen; leaf; flower initiation; thermal time; plastochron; phyllochron 相似文献
79.
Analysis of manganese and zinc concentrations in the scales of salmon and trout from a number of sites showed significant dependence of the levels of these metals in the scales on the levels in the environment. There is some evidence to suggest that in trout scales there is a minimum concentration of zinc above which there is a direct proportion between environmental and scale concentration. It is also possible that the response of trout to environmental zinc differs from that of salmon. 相似文献
80.