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   1145篇
  免费   10篇
  国内免费   71篇
化学   341篇
晶体学   2篇
力学   5篇
综合类   1篇
数学   25篇
物理学   852篇
  2024年   3篇
  2023年   35篇
  2022年   9篇
  2021年   3篇
  2020年   11篇
  2019年   52篇
  2018年   85篇
  2017年   10篇
  2016年   19篇
  2015年   7篇
  2014年   65篇
  2013年   77篇
  2012年   51篇
  2011年   79篇
  2010年   18篇
  2009年   22篇
  2008年   65篇
  2007年   104篇
  2006年   41篇
  2005年   55篇
  2004年   45篇
  2003年   35篇
  2002年   56篇
  2001年   42篇
  2000年   38篇
  1999年   35篇
  1998年   29篇
  1997年   23篇
  1996年   15篇
  1995年   14篇
  1994年   9篇
  1993年   13篇
  1992年   10篇
  1991年   6篇
  1990年   11篇
  1989年   4篇
  1988年   14篇
  1987年   11篇
  1985年   1篇
  1983年   1篇
  1982年   2篇
  1979年   1篇
排序方式: 共有1226条查询结果,搜索用时 15 毫秒
151.
本文研制了粉末涂料用柔韧性羧端基不饱和聚酯树脂及其相应的环氧树脂固化的柔韧性不饱和聚酯粉末涂料,讨论了树脂合成,涂料制备及涂层性能,涂层的装饰性能特别是柔韧性能有了较大改善。  相似文献   
152.
With years of training and performance, the mature vocal performer experiences less vocal changes with aging than does his/her age peer who is not a performer. We have considered, some physical problems that may adversely influence the voice of the older performer. With some awareness and effective management of these possible problems, the negative effects on the older performer's voice can be minimized.  相似文献   
153.
A convolution of Rayleigh functions with respect to the Bessel index can be treated as a special function in its own right. It appears in constructing global-in-time solutions for some semilinear evolution equations in circular domains and may control the smoothing effect due to nonlinearity. An explicit representation for it is derived which involves the special function ψ(x) (the logarithmic derivative of the Γ-function). The properties of the convolution in question are established. Asymptotic expansions for small and large values of the argument are obtained and the graph is presented.  相似文献   
154.
David J. Powner   《Journal of voice》2002,16(4):488-494
The objective of this study was to survey physician experts in voice disorders/treatment to establish consensus guidelines for translaryngeal intubation (TLI) and tracheotomy when treating professional singers or other voice professionals. A written survey was sent to all physician members of the Voice Foundation seeking opinions/recommendations about route of TLI, duration of TLI before tracheotomy, size of endotracheal and tracheotomy tubes, and special interventions during patient care as these might differ between professional singers and nonsingers. Fifty-five percent of the physicians responded, of whom 73% classified their experience in voice care as “extensive.” A strong consensus (76%) favored a smaller endotracheal tube for singers (6–7 mm I.D. for males and 6.0 mm I.D. for females) via the oral (46%) versus nasal (36%) route. Intubation/extubation by the most expert/experienced personnel was emphasized so as to minimize direct trauma to the larynx. While intubated, strong recommendations were made to suppress gastric acid production and to minimize motion of the endotracheal tube, including patient sedation. Preferences for an early tracheotomy (6 days) versus their usual time (10 days) were approximately equal (44% vs. 50%, respectively) and most respondents (69%) recommended the same size tracheotomy tube (8.0 mm I.D. for males and 6.0 mm I.D. for females) for singers and nonsingers. Post extubation/decannulation care emphasized voice rest, retraining, continued gastric acid suppression, and the possibility of direct laryngoscopy to assess post-TLI or tracheotomy injuries.  相似文献   
155.
This study was designed to evaluate a disease-specific outcome measure for patients with selected voice disorders and to relate this instrument to a standardized quality of life measurement. In addition, the study attempts to document the degree of handicap for dysphonia patients globally, between different vocal pathologies, and in comparison to other chronic diseases. In this prospective, observational study, 260 adult patients evaluated for alterations of voice completed a general quality of life measure (the Medical Outcomes Trust Short Form 36-Item[SF-36]) and a voice-specific instrument (Voice Handicap Index [VHI]) pretreatment.

The highest correlation was between the social functioning score of the SF-36and the total score of the VHI and the physical, emotional, and functional subscales (p < 0.001) of the VHI. Significant correlation was also obtained for the SF-36 domains mental health (p < 0.01), general health (p < 0.01), and role functioning emotional (p < 0.017) with the three VHI domains and the total VHI score. Patients had significantly lower scores than the general U.S. population in five of the eight domains of SF-36. Patients with vocal fold paralysis had the highest level of pretreatment disability as measured on both the VHI and SF-36 among voice patients. The patients with dysphonia had a lower level of physical functioning than the patients with chronic sinusitis (p < 0.01), reflecting a greater handicap. In addition, the dysphonia group had lower levels of social functioning than the angina (p < 0.01) and sciatica (p < 0.01) groups and a lower score for mental health than the angina group (p < 0.01).

The SF-36 correlates with the VHI in the domains of social functioning,mental health, and role functioning emotional. The baseline handicap for voice disorders represents a significant disability even in comparison to conditions such as angina pectoris, sciatica, and chronic sinusitis.  相似文献   

156.
This study was designed to examine the relationship between the Voice Handicap Index (VHI) and acoustic measures of voice samples common in clinical practice. Fifty participants, 38 women and 12 men, ranging in age from 19 to 80 years, with a mean age of 49 years, served as participants. Of these 50 participants, 17 participants could be included in the acoustic analysis of voice based on measures of error calculated with the TF32 software. All participants completed the VHI and provided voice samples including three trials of the sustained vowel /A/ at a comfortable loudness level as well as a connected speech sample consisting of the Zoo Passage. Acoustic measures were made with TF32 and Cool Edit software and included fundamental frequency, jitter %, shimmer %, signal-to-noise ratio, mean root-mean-square intensity, fundamental frequency standard deviation, aphonic periods, and breath groups. Results indicate that these measures were not predictive of overall VHI score, and no cohesive or predictable pattern was identified when comparing individual measures with overall VHI or with each subscale item. Likely contributions to this lack of correlation and subsequent clinical implications are discussed, as well as the direction for further research.  相似文献   
157.
158.
In a previous study, female patients in all age categories with a nonorganic dysphonia were found to report significantly more autonomic symptoms and complaints than healthy controls. This could not be confirmed for the male subgroup. The present study is to corroborate and nuance this observation by investigating larger groups, and to determine if, after voice therapy, the number of autonomic symptoms and complaints-particularly those ones that have no obvious relation to voice function-decreases. It is a prospective study with a matched control group; 184 patients with nonorganic dysphonia and 126 normal controls answered a questionnaire of 46 questions with 3 subsets and a consistency control. One hundred and one patients received functional voice therapy and completed the questionnaire before and after treatment. A matched control group of 42 normal subjects also filled in the questionnaire two times, with an interval of about 6 months. Neurovegetative symptoms and complaints-voice related and not related-are reported in highly significant excess by patients (especially but not exclusively females) with habitual nonorganic voice disorder. After therapy, there is a highly significant reduction in the number of autonomic symptoms and complaints (related or not related to voice), to such an extent that patients report on average no more general neurovegetative symptoms and complaints than healthy controls (even less). The number of neurovegetative symptoms and complaints connected with voice function is also strongly reduced in patients after therapy, but remains in significant excess when compared with controls.  相似文献   
159.
160.
A general structure of a linguistic classifier wherein sub-subclassifiers are the building blocks is suggested. Some properties of these sub-subclassifiers are proposed and proved. The physical significances of these properties are explored and it is shown that a condensed measure of belongingness of patterns to any class can be obtained which can conveniently be used for forming classification rules.  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