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   13865篇
  免费   1158篇
  国内免费   318篇
耳鼻咽喉   45篇
儿科学   235篇
妇产科学   146篇
基础医学   3510篇
口腔科学   140篇
临床医学   867篇
内科学   2394篇
皮肤病学   87篇
神经病学   2035篇
特种医学   194篇
外国民族医学   1篇
外科学   871篇
综合类   1257篇
现状与发展   3篇
一般理论   1篇
预防医学   989篇
眼科学   109篇
药学   1263篇
  2篇
中国医学   578篇
肿瘤学   614篇
  2024年   45篇
  2023年   207篇
  2022年   273篇
  2021年   538篇
  2020年   439篇
  2019年   425篇
  2018年   437篇
  2017年   452篇
  2016年   470篇
  2015年   557篇
  2014年   760篇
  2013年   963篇
  2012年   733篇
  2011年   777篇
  2010年   676篇
  2009年   727篇
  2008年   704篇
  2007年   635篇
  2006年   579篇
  2005年   497篇
  2004年   463篇
  2003年   348篇
  2002年   308篇
  2001年   285篇
  2000年   265篇
  1999年   187篇
  1998年   204篇
  1997年   167篇
  1996年   187篇
  1995年   180篇
  1994年   144篇
  1993年   168篇
  1992年   135篇
  1991年   118篇
  1990年   105篇
  1989年   109篇
  1988年   117篇
  1987年   70篇
  1986年   86篇
  1985年   99篇
  1984年   108篇
  1983年   63篇
  1982年   95篇
  1981年   68篇
  1980年   68篇
  1979年   70篇
  1978年   44篇
  1977年   39篇
  1976年   46篇
  1975年   26篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
IntroductionPregnancy in spinal cord injured patients has specific issues that must be carefully addressed. However, guidelines for their management are scarce.MethodsA systematic review of the literature regarding the anaesthetic management during delivery of pregnant patients with cervical spinal cord injury was performed on the electronic databases of PubMed (Medline) and Cochrane.ResultsA higher incidence of preterm birth and caesarean delivery were seen. Anaesthetic management was diverse, although most pregnant patients received epidural analgesia. Autonomic dysreflexia symptoms were present in 51% of pregnancies.ConclusionTimely management of these patients could possibly reduce caesarean and preterm delivery rates, avoid or minimize common complications, as well as reduce costs. An early reference to anaesthesiology consultation and a multidisciplinary approach is recommended.  相似文献   
2.
《Molecular therapy》2022,30(8):2856-2867
  1. Download : Download high-res image (173KB)
  2. Download : Download full-size image
  相似文献   
3.
4.
5.
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   
6.
7.
8.
The results of cardiovascular autonomic reflex tests on 224 healthy, randomly selected subjects were analysed to study possible sex differences in the autonomic responses. The heart rate response to the Valsalva manoeuvre (Valsalva ratio) was greater in females over 50 years than in males of the same age (1.58 ± 0.34 vs. 1.44 ± 0.30,p < 0.05). The heart rate response to deep breathing (E/I ratio) was higher in females under 50 years than in males under 50 years (1.37 ± 0.17 vs. 1.34 ± 0.18,p < 0.001). The diastolic blood pressure response to isometric handgrip was higher in males under 50 years than in females of the same age (p < 0.05). Although there were sex differences in the magnitude of the responses, the effect of age was similar in males and females and accelerated attenuation of the autonomic responses could not be demonstrated with increasing age. It can be concluded that significant sex differences exist in cardiovascular autonomic responses. The implication of such differences need consideration.  相似文献   
9.
目的 评价核酸或核苷酸用于临床营养支持和免疫调节治疗的安全性、有效性和经济学价值。方法 检索中国生物医学文献数据库、Cochrane图书馆、MEDLINE光盘数据库、EMBASE光盘数据库,并联机检索SCI数据库,鉴定有关随机对照试验(RCTs),采用RevMan4.l进行Meta-分析。结果 纳入46个随机对照试验,涉及核酸/核苷酸用于肠内营养支持、婴儿营养、免疫调节治疗。18个研究报告了含核苷酸组分的免疫增强型肠内营养对外科术后和危重症患者预后的影响,合并分析发现免疫营养对患者感染率、住院时间和费用有肯定意义。发现1个报告在母乳代用品中加入核苷酸对婴儿免疫功能影响的研究,但报告对临床结局无明显影响。27个对“免疫核酸”用于免疫调节治疗的随机对照试验均为低质量研究,合并分析无法肯定iRNA的临床价值。结论 在外科术后患者应用免疫肠内营养制剂可降低感染率、缩短住院时间并可能减少住院费用,但不能确定作为组分之一的核苷酸的作用。尚无证据支持在母乳代用品中添加核苷酸具有临床意义。不能肯定免疫核酸是否具有免疫调节作用,亦未发现核酸在延缓衰老、改善老年人健康状况方面的可用证据。建议对核酸、核苷酸用于营养支持治疗和免疫调节治疗进行进一步研究,严格规范“核酸营养品”的宣传和应用。  相似文献   
10.
目的:评价自主神经活动在高血压病中的调节作用。方法:观测100例高血压病(Ⅰ组)和54例正常人(Ⅱ组)及高血压病伴心电图改变(ⅠA组)和不伴心电图改变(ⅠB组)心率变异性(以下称HRV)时域参数SDNN、rMSSD、PNN50、Bottom4项指标。结果:Ⅰ组与Ⅱ组差异有显著性(P<0.05);ⅠA组与ⅠB组组差异无显著性(P>0.05)。结论:在高血压病中,交感神经张力增高,副交感神经活动减弱及损伤可能是HRV降低的重要因素。  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