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   19443篇
  免费   1620篇
  国内免费   601篇
耳鼻咽喉   1621篇
儿科学   652篇
妇产科学   137篇
基础医学   3168篇
口腔科学   518篇
临床医学   2039篇
内科学   3459篇
皮肤病学   36篇
神经病学   3527篇
特种医学   342篇
外科学   1021篇
综合类   2483篇
现状与发展   1篇
预防医学   943篇
眼科学   113篇
药学   1015篇
  6篇
中国医学   444篇
肿瘤学   139篇
  2024年   43篇
  2023年   403篇
  2022年   502篇
  2021年   1085篇
  2020年   1088篇
  2019年   816篇
  2018年   784篇
  2017年   867篇
  2016年   811篇
  2015年   721篇
  2014年   1235篇
  2013年   1296篇
  2012年   1016篇
  2011年   1041篇
  2010年   982篇
  2009年   1067篇
  2008年   1044篇
  2007年   964篇
  2006年   794篇
  2005年   659篇
  2004年   543篇
  2003年   477篇
  2002年   427篇
  2001年   350篇
  2000年   316篇
  1999年   294篇
  1998年   260篇
  1997年   179篇
  1996年   123篇
  1995年   141篇
  1994年   108篇
  1993年   122篇
  1992年   121篇
  1991年   55篇
  1990年   60篇
  1989年   56篇
  1988年   52篇
  1987年   48篇
  1986年   51篇
  1985年   79篇
  1984年   82篇
  1983年   65篇
  1982年   82篇
  1981年   62篇
  1980年   71篇
  1979年   49篇
  1978年   46篇
  1977年   30篇
  1976年   20篇
  1975年   19篇
排序方式: 共有10000条查询结果,搜索用时 453 毫秒
11.
BackgroundIdentifying electroencephalogram (EEG) cortical arousals are crucial in scoring hypopneas and respiratory efforts related arousals (RERAs) during a polysomnogram. As children have high arousal threshold, many of the flow limited breaths or hypopneas may not be associated with visual EEG arousals, hence this may lead to potential underestimation of the degree of sleep disordered breathing. Pulse wave amplitude (PWA) is a signal obtained from finger photoplethysmography which correlates directly to finger blood flow. The drop in PWA has been shown to be a sensitive marker for subcortical/autonomic and cortical arousals. Our aim was to use the drop in PWA as a surrogate for arousals to guide scoring of respiratory events in pediatric patients.MethodsTen polysomnograms for patients between the ages of 5–15 years who had obstructive apnea-hypopnea indices between 1 and 5 events/hour were identified. Patients with syndromes were excluded. A drop in PWA signal of at least 30% that lasted for 3 s was needed to identify subcortical/autonomic arousals. Arousals were rescored based on this criteria and subsequently respiratory events were rescored. Paired t-tests were employed to compare PSG indices scored with or without PWA incorporation.ResultsThe sample of 10 children included 2 females, and the average age was 9.8 ± 3.1 years. Overall, polysomnography revealed an average total sleep time of 464.1 ± 25 min, sleep efficiency of 92% +/−4.2, sleep latency of 19.6 ± 17.0 min, rapid eye movement (REM) latency 143 ± 66 min, N1 3.9% +/−2.0, N2 50.3% +/−12.0, N3 28.2% +/−9.1, REM 16.7% +/−4.0, and wakefulness after sleep onset (WASO) 18.1 ± 7.5 min. Including arousals from PWA changes, respiratory indices significantly increased including total AHI (2.3 ± 0.7 vs 5.7 ± 2.1, p < 0.001), obstructive AHI (1.45 ± 0.7 vs 4.8 ± 1.8, p < 0.001), and RDI (2.36 ± 0.7 vs 7.6 ± 2.0, p < 0.001). Likewise, total arousal index was significantly higher (8.7 ± 2.3 vs 29.4 ± 6.5, p < 0.001).ConclusionsThe drop in pulse wave amplitude signal is a useful marker to guide scoring arousals that are not otherwise easily identified in pediatric polysomnography and subsequently helped in scoring respiratory events that otherwise would not be scored. Further studies are needed to delineate if such methodology would affect clinical outcome.  相似文献   
12.
《Cor et vasa》2015,57(3):e157-e162
IntroductionObstructive sleep apnea (OSA) is often connected with arterial hypertension and it could also be a cause of secondary hypertension. Treatment of arterial hypertension and optimal blood pressure level are important for prevention of cardiovascular complications. It is not well known how to treat patients with OSA and arterial hypertension. Also many patients with OSA suffer from metabolic syndrome which worsen their prognosis.AimThe aim of our study was to assess arterial hypertension compensation in patients with metabolic syndrome and moderate to severe OSA and to analyze used pharmacotherapy.Materials and methods85 hypertensive patients (75 men) with metabolic syndrome, average age 53.6 ± 9.3 years, were evaluated using overnight sleep study with diagnosis of OSA, average apnea–hypopnea index (AHI) 56.3 ± 23. Patients underwent 24 h ambulatory blood pressure monitoring (ABPM) and their current pharmacotherapy data were obtained. Appropriate combinations of antihypertensive drugs (patients with metabolic syndrome) were derived from ESH/ESC 2013 guidelines.ResultsArterial hypertension was well compensated in only 11.8% of the patients. 24.7% patients were treated according to current guidelines. Fisher's exact test with analysis of adjusted residues has found higher rate of blood pressure subcompensation in patients treated with triple+ combination of drugs (p = 0.035, 51.4% vs 10%).ConclusionOnly a small number of patients had optimal blood pressure level and were treated according to current ESH/ESC guidelines. We have to constantly appeal to all physicians to perform ABPM in patients with OSA.  相似文献   
13.
14.
15.
李源  李瑞英  孙明英 《河南中医》2020,40(4):601-604
目的:观察疏风宣肺止嗽汤对咳嗽变异性哮喘患儿肺功能及睡眠质量的影响。方法:将70例咳嗽变异性哮喘患儿按照随机数字表法分为对照组和观察组,每组各35例。对照组给予常规西医治疗,观察组在对照组的基础上加用自拟疏风宣肺止嗽汤治疗。比较两组患儿的临床疗效、症状消失时间、住院时间、不良反应发生率、复发率及治疗前后中医证候积分、匹兹堡睡眠质量指数(pittsburgh sleep quality index,PSQI)、肺功能指标变化情况。结果:观察组有效率为94.29%,对照组有效率为77.14%,两组患儿有效率比较,差异具有统计学意义(P<0.05)。观察组复发率低于对照组,差异具有统计学意义(P<0.05)。两组患儿治疗后中医证候评分及PSQI评分低于本组治疗前,且观察组治疗后低于对照组治疗后,差异具有统计学意义(P<0.05)。两组患儿治疗后肺功能指标高于本组治疗前,且观察组治疗后高于对照组治疗后,差异具有统计学意义(P<0.05)。观察组患儿症状消失时间及住院时间短于对照组,差异具有统计学意义(P<0.05)。结论:自拟疏风宣肺止嗽汤治疗咳嗽变异性哮喘,能够改善患儿的临床症状、肺功能及睡眠质量。  相似文献   
16.
17.
18.
BackgroundResearchers have proposed that impaired sleep may be a causal link in the progression from Mild Cognitive Impairment (MCI) to Alzheimer's Disease (AD). Several recent findings suggest that enhancing deep sleep (N3) may improve neurological health in persons with MCI, and buffer the risk for AD. Specifically, Transcranial Electrical Stimulation (TES) of frontal brain areas, the inferred source of the Slow Oscillations (SOs) of N3 sleep, can extend N3 sleep duration and improve declarative memory for recently learned information. Recent work in our laboratory using dense array Electroencephalography (dEEG) localized the sources of SOs to anterior limbic sites – suggesting that targeting these sites with TES may be more effective for enhancing N3.MethodsFor the present study, we recruited 13 healthy adults (M = 42 years) to participate in three all-night sleep EEG recordings where they received low level (0.5 mA) TES designed to target anterior limbic areas and a sham stimulation (placebo). We used a convolutional neural network, trained and tested on professionally scored EEG sleep staging, to predict sleep stages for each recording.ResultsWhen compared to the sham session, limbic-targeted TES significantly increased the duration of N3 sleep. TES also significantly increased spectral power in the 0.5–1 Hz frequency band (relative to pre-TES epochs) in left temporoparietal and left occipital scalp regions compared to sham.ConclusionThese results suggest that even low-level TES, when specifically targeting anterior limbic sites, can increase deep (N3) sleep and thereby contribute to healthy sleep quality.  相似文献   
19.
20.
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