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   620篇
  免费   6篇
化学   13篇
力学   4篇
数学   2篇
物理学   607篇
  2023年   2篇
  2022年   1篇
  2021年   3篇
  2020年   1篇
  2019年   43篇
  2018年   81篇
  2017年   2篇
  2016年   4篇
  2015年   2篇
  2014年   57篇
  2013年   7篇
  2012年   3篇
  2011年   57篇
  2010年   2篇
  2009年   3篇
  2008年   28篇
  2007年   35篇
  2006年   20篇
  2005年   30篇
  2004年   29篇
  2003年   18篇
  2002年   23篇
  2001年   24篇
  2000年   24篇
  1999年   18篇
  1998年   20篇
  1997年   15篇
  1996年   11篇
  1995年   12篇
  1994年   5篇
  1993年   8篇
  1992年   7篇
  1991年   3篇
  1990年   6篇
  1989年   2篇
  1988年   12篇
  1987年   7篇
  1986年   1篇
排序方式: 共有626条查询结果,搜索用时 0 毫秒
51.

Objectives

Teachers are at increased risk for developing voice disorders. Occupational risk factors have been extensively examined; however, little attention has been paid to the consequences of the vocal complaints. The objective of this study was to investigate the knowledge that teachers have about vocal care, treatment-seeking behavior, and voice-related absenteeism.

Methods

The study group comprised 994 teachers and 290 controls whose jobs did not involve vocal effort. All participants completed a questionnaire inquiring about vocal complaints, treatment-seeking behavior, voice-related absenteeism, and knowledge about vocal care. Comparisons were made between teachers with and without vocal complaints and with the control group.

Results

Teachers reported significantly more voice problems than the control population (51.2% vs 27.4%) (χ2 = 50.45, df = 1, P < 0.001). Female teachers reported significantly higher levels of voice disorders than their male colleagues (38% vs 13.2%, χ2 = 22.34, df = 1, P < 0.001). Teachers (25.4%) sought medical care and eventually 20.6% had missed at least 1 day of work because of voice problems. Female teachers were significantly more likely to seek medical help (χ2 = 7.24, df = 1, P = 0.007) and to stay at home (χ2 = 7.10, df = 1, P = 0.008) in comparison with their male colleagues. Only 13.5% of all teachers received information during their education.

Conclusions

Voice disorders have an impact on teachers' personal and professional life and imply a major financial burden for society. A substantial number of teachers needed medical help and was obligated to stay at home because of voice problems. This study strongly recommends the implementation of vocal education during the training of teacher students to prepare the vocal professional user.  相似文献   
52.
53.
Thyroplasty is the most commonly performed type of laryngeal framework surgery, and the surgical indications are gradually being expanded. Although many reports have described thyroplasty results and rates of success, no study has attempted to determine predictors of the need for revisions or other secondary surgical procedures. METHODS: Retrospective review of 118 primary thyroplasty procedures performed on 96 patients. Secondary surgical procedures were divided into planned second-stage procedures (all fat implantation due to scarring), touchup procedures (primarily fat or collagen injections to close localized glottic gaps), and thyroplasty revisions (for implant extrusion or slippage). Statistical analysis was performed via the chi-squared technique with p < 0.05 considered significant. RESULTS: 96 patients underwent thyroplasty, 58 for vocal fold paresis or paralysis and 38 for other indications. Thirty-two (33%) patients underwent secondary surgical procedures, including 4 planned second stage procedures, and 6 patients with progression of their underlying disease. Thirty-two secondary procedures were performed in the other 22 patients. Professional singers were found to be more likely to require touchup or planned second-stage procedures (p = 0.029). Patients with abnormal preoperative noise-toharmonic ratios were more likely to undergo secondary surgeries (p = 0.039). Maximum phonation time was not associated with need for secondary surgery. Implant material did not influence revision rates. CONCLUSIONS: Professional singers and those patients with severe voice disorders (as measured by more abnormal noise-to-harmonic ratios) are more likely to undergo secondary surgical procedures. The choice of implant material does not affect need for secondary surgical procedures.  相似文献   
54.
王学林  胡于进 《力学学报》2012,44(3):622-630
蜗窗驱动是实现中耳听力装置与耳蜗耦合的新途径. 利用外耳道、中耳和耳蜗集成有限元模型, 分别模拟外耳道声激励经听骨链、前庭窗传入内耳的正向传递过程和蜗窗机械激励在耳中逆向传递过程, 计算获得中耳和耳蜗的传递函数. 比较蜗窗激励和外耳道激励下耳蜗基底膜的振动, 提出了以基底膜最佳反应部位位移相等为准则的蜗窗等效激励力计算方法. 理论计算获得的蜗窗等效激励力与相关文献根据实验数据预测结果一致. 计算结果还表明耳蜗窗正、逆向激励时, 基底膜上最佳反应部位无变化, 但在蜗窗逆向激励耳蜗时, 低频下驱动基底膜运动的效率比高频时低. 所获得的理论结果可为蜗窗驱动的听力装置设计和现有装置的应用提供参考.  相似文献   
55.
56.
57.
58.
59.
60.
High-speed filming is one of the most informative methods for assessing voice physiology data. Tracing high-speed images of the glottis provides quantitative parameters such as the glottal area and the glottal width function. By way of example, a number of studies are discussed which extract quantitative data from high-speed images showing voice onsets. Furthermore, a new computer system (MVAS; multi-dimensional voice analysis system) is presented that synchronously displays a laryngoscopic high-speed film, the electroglottographical signal, and several acoustic analyses of the recorded voice sample. The automatic measurement of glottal width and glottal area from the laryngoscopic images is also provided. Looking at former studies and our analyses of voice onsets reveals a tremendous intersubject and even intrasubject variability (different prephonatory closure, different time span until full amplitude is reached, different open quotient).  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