首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   137篇
  免费   6篇
  国内免费   6篇
系统科学   3篇
丛书文集   3篇
教育与普及   1篇
现状及发展   19篇
综合类   123篇
  2023年   2篇
  2022年   3篇
  2021年   5篇
  2020年   4篇
  2019年   4篇
  2017年   6篇
  2016年   2篇
  2015年   5篇
  2014年   6篇
  2013年   3篇
  2012年   8篇
  2011年   13篇
  2010年   4篇
  2009年   8篇
  2008年   9篇
  2007年   13篇
  2006年   5篇
  2005年   4篇
  2004年   5篇
  2003年   4篇
  2002年   4篇
  2001年   2篇
  2000年   3篇
  1999年   4篇
  1998年   3篇
  1996年   1篇
  1994年   2篇
  1993年   4篇
  1992年   4篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
排序方式: 共有149条查询结果,搜索用时 31 毫秒
1.
Periodic circadian (24-h) cycles play an important role in daily hormonal and behavioural rhythms. Usually our sleep/wake cycle, temperature and melatonin rhythms are internally synchronized with a stable phase relationship. When there is a desynchrony between the sleep/wake cycle and circadian rhythm, sleep disorders such as advanced and delayed sleep phase syndrome can arise as well as transient chronobiologic disturbances, for example from jet lag and shift work. Appropriately timed bright light is effective in re-timing the circadian rhythm and sleep pattern to a more desired time, ameliorating these disturbances. Other less potent retiming effects may also be obtained from the judicious use of melatonin and exercise.  相似文献   
2.
Summary In the realm of human circadian rhythms, the masking effect is defined as the change in the course of deep body temperature induced by changes in the degree of physical activity, or by the alteration between sleep and wake. This effect is particularly obvious during internal desynchronization where the rhythms of deep body temperature, and the sleep-wake sleep-wake sleep cycle — i.e. one of the masking factors — run with different periods.Every sleep onset is accompanied by a rapid drop, and wake onset by a rapid rise in deep body temperature, each one with an overshoot of about 50% of the steady state variations. When rhythms are calculated, with the dominant temperature period as the screening period, exclusively from data obtained during sleep episodes, on the one hand, and from those obtained exclusively during wake, on the other, two average cycles emerge: the sleep temperature curve and the wake temperature curve. Both run in parallel but are separated by the masking effcct. As derived from many experiments, the mean masking effect amounts to 0.28±0.06°C. The masking effect also depends to some extent on the phase of the temperature rhtthm; it is larger than average around the temperature maximum and during the descending phase of the temperature cycle, where the alertness commonly is highest and the probability to sleep, in general, and the REM sleep propensity, in particular, are smaller than average. This also can be interpreted to indicate that the sleep temperature curve is phase advanced relative to the wake temperature curve; this, on the average, by 0.9±0.3 h.If the individually determined amount of masking is added to the temperature data obtained during sleep, or substracted from the temperature data obtained during wake, a temperature curve emerges that can be though of as being purified of the masking effect. Analyses of this artificial curve allow estimation of that part of the internal interactions uninfluenced by the masking effect. On the average, about half of the amount of interaction between the rhythm of sleep-wake and that of deep body temperature is explained by the masking effect, whereas the other half is oscillatory interaction. Both types of interaction are inherent and inseparable parts of the circadian clock mechanism, as can be deduced from model considerations.  相似文献   
3.
介绍了基于网络的睡眠监护与分析系统的软硬件设计方案.对系统设计中需要解决的网络数据传输.图形实时显示.以及数据库管理等一些关键性的问题.提出了解决方法.基于这些方法进行了初步的系统实验.取得了较为满意的效果.本系统可望成为未来数字化家庭的重要医疗单元和今后进一步开展远程医疗研究的基础.  相似文献   
4.
目的探讨家庭长期氧疗(LTOT)对慢性阻塞性肺疾病(COPD)患者的疗效。方法将我院同期住院病人随机分为治疗组和对照组各45人,治疗组患者定时供氧,给予15h/d以上的氧疗,应用压缩氧气、鼻导管给氧法,氧流量2L/min。两组治疗周期均为1年,对两组病人进行连续1年追踪随访,根据病情1-3个月随诊1次,全部患者治疗前后复查血气分析、肺功能。结果晚期COPD患者缓解期行长期LTOT,VC、FVC、FEV1明显改善,长期氧疗组治疗后动脉血氧分压水平上升,与治疗前比较,差异均有显著性意义,而且与对照组比较也有明显提高,差异有显著性,动脉血二氧化碳分压下降,与对照组差异显著性。结论合理使用LTOT可提高肺泡内氧分压,增加氧弥散能力,增加组织供氧,降低肺动脉压力,减轻呼吸困难程度,提高生活质量。  相似文献   
5.
阻塞性睡眠呼吸暂停综合症的观察及护理   总被引:5,自引:0,他引:5  
通过对55例阻塞性睡眠呼吸暂停综合症患者术前、术后的护理及观察,总结了护理体会,着重对术前、术后健康教育及心理、术后伤口出血情况,气管切开护理,咽部水肿,饮食及口腔清洁,并发症观察护理进行了总结,并通过术前,术后血氧饱和度、呼吸、心率的监测,总结了阻塞性睡眠呼吸暂停综合症患者的手术疗效。  相似文献   
6.
Recent findings concerning human slow wave sleep (hSWS-stages 3+4; delta EEG activity) are critically reviewed. Areas covered include the significance of the first hSWS cycle; hSWS in extended sleep; relationship between hSWS, prior wakefulness and sleep loss; hSWS influence on sleep length; problems with hSWS deprivation; influence of the circadian rhythm; individual differences in hSWS, especially, age, gender and constitutional variables such as physical fitness and body composition. Transient increases in hSWS can be produced by increasing both the quality and quantity of prior wakefulness, with an underlying mechanism perhaps relating to the waking level of brain metabolism. Whilst there may also be thermoregulatory influences on hSWS, hypotheses that energy conservation and brain cooling are major roles for hSWS are debatable. hSWS seems to offer some form of cerebral recovery, with the prefrontal cortex being particularly implicated. The hSWS characteristics of certain forms of major psychiatric disorders may well endorse this prefrontal link.  相似文献   
7.
为考察灵芝培养基在添加不同中药后,其发酵液药理作用的变化,选择小鼠负重游泳实验,戊巴比妥钠睡眠时间试验,小鼠断头后致急性脑缺氧试验,以及对S180荷瘤小鼠瘤重的影响,研究在灵芝培养基中添加不同中药后其发酵液的抗疲劳、改善睡眠、耐缺氧与抑制肿瘤作用,并研究了这几味中药对灵芝生长的影响.结果发现在灵芝培养基中添加黄芪、姜黄、补骨脂、红毛五加后,其发酵液能明显延长小鼠负重游泳时间;在培养基中添加黄芪、红毛五加的发酵液对小鼠急性脑缺血性缺氧具有较好的保护作用;在培养基中添加巴戟天后,其发酵液灌胃的小鼠,瘤重减轻.表明在灵芝培养基中添加中药后,会改变灵芝发酵液的药理作用.  相似文献   
8.
目前社会上流行各种各样的增高方法,其中很多是毫无科学道理的,存在严重的误导消费行为。影响青少年身高增长主要因素很多,如睡眠、体育锻炼和营养补钙等,注意这些可以为青少年拥有理想身高提供帮助。中国城市儿童普遍缺乏体育锻炼及睡眠不足应引起高度重视。  相似文献   
9.
采用彩色多普勒超声对30例正常人(A组)和36例阻塞性黄疸患者(B组)的门静脉,肝、脾、肾动脉血流动力学进行研究,结果表明:①阻塞性黄疸病人门脉血流速度低于正常人(P<005);②肝、脾、肾动脉阻力指数阻塞性黄疸病人较正常人明显增加(P<001),而门静脉血流量仍在正常范围。进一步证明阻塞性黄疸血流动力学的变化对人体病理生理所造成的影响。  相似文献   
10.
睡眠剥夺影响大脑功能区状态的非线性评价   总被引:2,自引:0,他引:2  
采用近似熵研究睡眠剥夺(sleep deprivation,SD)对脑认知功能的影响,评价SD引起的大脑功能区状态的非线性变化.12名受试者在正常睡眠和一夜SD之后分别接受视觉注意力测试,记录自发脑电和诱发脑电,采用二维插值构建19导脑电近似熵脑信息图(brain information map,BIM).结果表明,在SD状态下,自发脑电的近似熵在全脑范围内有不同程度的下降,额叶处大脑偏侧性发生变化,复杂度的中心从左脑转移到右脑;前额叶处诱发脑电近似熵值降低,而顶叶和颞叶处则升高.脑电近似熵可以作为指标来评价SD对脑认知功能的负向影响,BIM的变化趋势与从生理学及影像学角度的分析相吻合,与线性方法的研究结论一致,在一定程度上可以反映大脑功能状态,提供一条评价脑功能区状态变化趋势的思路.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号