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   485篇
  免费   2篇
化学   6篇
力学   5篇
综合类   1篇
数学   3篇
物理学   472篇
  2024年   1篇
  2022年   2篇
  2020年   2篇
  2019年   22篇
  2018年   46篇
  2017年   3篇
  2014年   51篇
  2013年   6篇
  2011年   46篇
  2010年   3篇
  2009年   3篇
  2008年   13篇
  2007年   23篇
  2006年   15篇
  2005年   21篇
  2004年   18篇
  2003年   18篇
  2002年   20篇
  2001年   16篇
  2000年   22篇
  1999年   26篇
  1998年   23篇
  1997年   16篇
  1996年   13篇
  1995年   12篇
  1994年   2篇
  1993年   10篇
  1992年   4篇
  1991年   8篇
  1990年   7篇
  1989年   3篇
  1988年   7篇
  1987年   5篇
排序方式: 共有487条查询结果,搜索用时 0 毫秒
461.
Abnormal vocal cord mobility may result from trauma to the cricoarytenoid joint. A rabbit model of this kind of trauma was established in order to investigate pathological changes of the traumatized joint. Two types of pathological changes in the cricoarytenoid joint (acute inflammatory reaction in the early stage and fibrosis in the later stage) were noted. The above phenomena might be the mechanism of vocal cord dysfunction caused by trauma to the cricoarytenoid joint. The recovery of vocal cord function may depend on whether or not there is fibrosis of the cricoarytenoid joint. It is almost impossible to regain normal vocal cord function as soon as fibrosis of the joint occurs. Therefore, it is important to treat the patients effectively and immediately in the early stage of trauma for recovery.  相似文献   
462.
The phonetogram has been recommended as an international tool for voice analysis. However, the capability of this technique to distinguish between different vocal groups has not been clearly established. The purpose of this study was to examine untrained versus trained vocalists using the phonetogram and the fundamental frequency by intensity (F0/SPL) information derived through that method. In this study, “musical” or “controlled” ranges of phonation were stressed rather than “physiological” ranges. Results indicated that (a) characteristic phonetographic profiles may be established for untrained versus trained vocalists, and (b) trained vocalists show significantly increased capability in terms of F0 range and maximum, minimum, and comfortable SPL production. Elicitation of “controlled” phonations may be the key to revealing the underlying vocal capabilities of seemingly different vocal groups.  相似文献   
463.
Otolaryngology and voice science have entered the era of “phonosurgery.” Several techniques allow voice professionals to intervene to restore or modify the voice in patients with immobile vocal folds and other problems related to voice production. It is necessary and appropriate that physicians and speech and language pathologists critically examine what has been accomplished and what may yet be possible for further voice improvement.  相似文献   
464.
Simultaneous measurements of mean airflow rate, vocal intensityand fundamental frequency were made during flexible video endoscopic recording of the vowel /i/ sustained in two vocal registers, modal and falsetto. The glottal closure patterns of four males and four females were evaluated by visually inspecting the video images. Acoustic signals were recorded and analyzed to verify the frequency and intensity criteria. Aerodynamic analysis of mean airflow rate was done via Rothenberg mask and commercial software. Incomplete glottic closure was common in both males and females. The degree of closure was significantly higher for modal samples than for falsetto samples with frequency and intensity held constant. The shape of the glottal closure did not vary with changes in the mode of phonation. As expected, the mean airflow rate increased with decreased glottal closure. The results suggest that incomplete glottic closure should be considered as a normal glottal configuration in high frequency modal and falsetto phonation. Moreover, hourglass and spindle glottal configurations may also be found in both the modal and falsetto registers of normal subjects. These results also confirm the positive relationships between degree of glottal gap and mean airflow rate. Thus, mean airflow rate may be regarded as a criterion for judging degree of glottal closure.  相似文献   
465.
The purpose of this investigation was to examine changes in glottal configuration in women under a variety of pitch and loudness conditions after an interval of loud reading. Twelve young adult women with normal laryngeal structures were photographed under stroboscopic light and sustained the vowel /i/ for a minimum of 3 s, at three pitch levels and three loudness levels, before and after a 15-min interval of loud reading. Results indicate that female speakers tend to alter glottic configurations across phonatory conditions after loud reading, particularly during high-pitch phonation. Specifically, five subjects tended to increase glottal closure, one tended to increase glottal opening, two tended to maintain the identical configuration, and four demonstrated no consistent pattern of response.  相似文献   
466.
The fundamental frequency (F0) characteristics of 19 male patients with advanced laryngeal cancer, treated with cisplatin-based chemotherapy as part of a Larynx Preservation Protocol (LPP), were measured before each of three cycles of chemotherapy received before definitive radiotherapy (RT). In these select patients, for whom chemotherapy resulted in 50% decrease in the tumor bulk, it was found that mean F0 was essentially unaffected by the disease and did not change over the course of chemotherapy, although the cycle of their treatment could be differentiated by both speaking F0 variability (pitch sigma) and F0 perturbation (fitter). Although these measures failed to distinguish between those patients showing a complete response (CR) (no measurable disease) versus a partial (PR) (residual) tumor response at the primary disease site, the significant changes observed in both groups indicate that frequency variation measures could prove valuable in the documentation of tumor response to nonsurgical therapeutic intervention if the voice is directly affected. Additional assessment of 15 age- and disease-matched patients who showed minimal or no primary response to the chemotherapy showed no significant change in any of the frequency measures after one chemotherapy cycle, suggesting that vocal improvement seen in the successful chemotherapy patients was not due to postbiopsy healing or other systemic influence unassociated with tumor reduction.  相似文献   
467.
This diverse group is described in relation to life stage, short- and long-range performance objectives, and lifestyle factors pertinent to vocal health. Physical, behavioral, cognitive, and psychosocial issues relevant to assessment and intervention will be addressed. The possible dissonance between a clinician's developmental perspective and a client's immediate pragmatic concerns is discussed. In addition, the specific challenges of dealing with adolescents (e.g., the influence of the peer group, the emergence of autonomy, the redefinition of relationships with significant adults, and the vulnerability of the mechanism) are related to clinical problem solving.  相似文献   
468.
David M. Howard   《Journal of voice》2007,21(3):300-315
OBJECTIVES/HYPOTHESIS: When a soprano, alto, tenor, bass (SATB) quartet sings unaccompanied, or a capella, the members of the group will tend to make use of non-equal-tempered intonation to govern their tuning. If the music they are performing visits different keys and they do maintain non-equal-tempered tuning, then the pitch center will have to shift from its starting point, which is a necessary consequence of the physics behind the use of a non-equal-tempered tuning system. The implication of this shift for tuning in a capella singing is that it is not possible both to maintain accurate non-equal-tempered tuning and to stay in pitch throughout music that modulates in key. METHODS: To test this notion, a set of four-part exercises were written by the author that visit several different key chords in sequential progression. In each case, the starting and finishing chords were either identical or exactly an octave apart. Mean fundamental frequency values for each note were measured using four electrolaryngographs (one per singer), and the f0 data were normalized and plotted with respect to equal-tempered tuning to enable any overall tuning shift to be observed. RESULTS: The results indicate that singers do (1) tend to non-equal-tempered tuning and (b) do consequentially shift their intonation with modulation. CONCLUSIONS: These data indicate that pitch drift is potentially a necessary part of staying in-tune. Further work is required to identify items in the choral repertoire for which this effect is likely and then to inform the choral conducting and singing communities appropriately.  相似文献   
469.
SUMMARY: After years of treatment with the medication levodopa, most individuals with Parkinson disease (PD) experience fluctuations in response to their medications. Although relatively consistent perceptual voice improvements have been documented to correspond with these fluctuations, consistent quantitative data to support this finding are lacking. This mismatch may have occurred because most of this phonation research has centered on long-term phonatory measures (ie, across speaking samples and prolonged vowel tasks). The current study examined short-term phonatory behavior in individuals with PD, specifically examining fundamental frequency (F0) at the offset and onset of phonation, before and after a voiceless consonant. The F0 analysis at phonatory offset supported the conclusion that individuals with PD have difficulty with the rapid offset of voicing, and that they are stopping vocal fold vibration primarily through vocal fold abduction (without adding tension). The F0 analysis at phonatory onset revealed that all groups use some laryngeal tension at the initiation of voicing. The tension was lowest for the PD participants who were in their OFF medication state, and it was highest for the age-matched control participants and the PD participants in their ON medication states.  相似文献   
470.
SUMMARY: The rehabilitation of glottic incompetence by injection laryngoplasty is important in the management of thoracic surgery patients with vocal cord paralysis. This group of patients presents special considerations that favor injection under local anesthesia. The objective of this study is to characterize our experience with this minimally invasive approach in both the acute and subacute settings. The study was conducted using a retrospective chart review. From a database of 108 patients who received awake percutaneous injection laryngoplasty over a 3-year period, 15 cases were identified that underwent augmentation shortly following thoracic surgery. These records were reviewed for patient demographics, clinical characteristics, complications, and short-term outcomes. Fifteen patients were identified (12 male, 3 female); the age range for the group was 18-91 years (median=55 years). All the patients reported vocal improvement following injection; all 15 also were improved by perceptual assessment. Five of six dysphagic patients improved following injection. One patient's injection was aborted due to vocal fold edema; no significant bleeding or airway embarrassment was observed. No procedures were terminated because of patient discomfort. Awake percutaneous injection laryngoplasty for vocal paralysis can be performed safely in the postoperative thoracic surgery patient. Swallowing and voice complaints were almost universally improved following treatment. For patients who cannot tolerate or choose not to have open thyroplasty or vocal fold injection under general anesthesia, this procedure may offer a safe and effective alternative.  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