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   541篇
  免费   31篇
耳鼻咽喉   4篇
儿科学   6篇
妇产科学   13篇
基础医学   63篇
口腔科学   4篇
临床医学   81篇
内科学   69篇
皮肤病学   1篇
神经病学   62篇
特种医学   23篇
外科学   74篇
综合类   12篇
一般理论   1篇
预防医学   76篇
眼科学   19篇
药学   38篇
肿瘤学   26篇
  2022年   6篇
  2021年   8篇
  2020年   6篇
  2019年   6篇
  2018年   6篇
  2017年   5篇
  2016年   9篇
  2015年   8篇
  2014年   13篇
  2013年   22篇
  2012年   35篇
  2011年   28篇
  2010年   11篇
  2009年   8篇
  2008年   31篇
  2007年   26篇
  2006年   25篇
  2005年   26篇
  2004年   23篇
  2003年   23篇
  2002年   16篇
  2001年   11篇
  2000年   8篇
  1999年   17篇
  1998年   6篇
  1997年   3篇
  1996年   6篇
  1993年   5篇
  1992年   13篇
  1991年   9篇
  1990年   11篇
  1989年   12篇
  1988年   6篇
  1987年   6篇
  1986年   7篇
  1985年   9篇
  1984年   10篇
  1983年   12篇
  1982年   6篇
  1981年   7篇
  1979年   8篇
  1978年   5篇
  1977年   5篇
  1975年   3篇
  1971年   10篇
  1970年   4篇
  1968年   3篇
  1967年   7篇
  1966年   5篇
  1961年   2篇
排序方式: 共有572条查询结果,搜索用时 15 毫秒
41.
BACKGROUND: An innovative encircling guidewire defines three sides of a target lesion with a single puncture to achieve negative margins. METHODS: Twenty-five patients requiring image-guided surgery were localized with an encircling guidewire. Although the deployed wire is circular, it is straight when placed, using a straight outer needle. After image-guided placement of the wire around the lesion, all patients underwent standard surgical excision. Each patient was categorized by proper localization of the target lesion, presence of negative margins, closest margin, and need for reexcision. RESULTS: The circlewire wire identified the target lesion in all cases. There were no complications relative to either version of the leading tip on the guidewire. Negative margins were achieved in all pure invasive ductal carcinomas. Positive margins were found in all 3 patients with extensive noncalcified in-situ disease and 1 patient with multifocal invasive lobular carcinoma. CONCLUSIONS: An innovative encircling localizing guidewire device gives the surgeon a new option to completely remove a nonpalpable breast lesion.  相似文献   
42.
PURPOSE: To determine whether prevention of hyposalivation after curative radiotherapy (RT) to the head and neck improves patients' quality of life (QOL). METHODS AND MATERIALS: Patients were to receive at least 50 Gy to 50% of the volume of the major salivary glands, provide unstimulated and stimulated saliva samples, and complete the University of Washington head-and-neck QOL tool before RT and 3 and 6 months after RT. Patients were randomized to receive pilocarpine 5 mg or placebo q.i.d. RESULTS: A total of 249 patients was randomized between March 1998 and January 2000. Of these, 214 were eligible for QOL analysis. Patients were evenly distributed between arms by race, gender, tobacco use, tumor site, T stage (50% T2-T3), and salivary function. A Karnofsky performance status of 90% was more common in the pilocarpine arm. Twenty percent of the patients on the pilocarpine arm and 29% of the patients on the placebo arm were taking nutritional supplements. The placebo arm patients had greater mouth pain and chewing difficulties. Compliance for the QOL tool at 3 and 6 months was 65% and 50%, respectively. Despite statistically significant (p = 0.047 and p = 0.049, respectively) preservation of salivary function in the pilocarpine arm, patients on the pilocarpine arm reported difficulties with swallowing (75%), activity (80%), hyposalivation (64%), and taste (81%). No difference was noted between arms at 3 months in mucositis scores, with both arms demonstrating increased requirement for oral nutrients. CONCLUSION: Objective prevention of hyposalivation did not affect patients' assessment of salivary function or QOL because of the greater impact mucositis plays in QOL after RT.  相似文献   
43.
44.
An in vitro study was performed to evaluate the effect of four variables on the temperature rise produced by the finishing of restorations. The four variables were: restorative material, finishing agent, finishing time, and depth of dentin under the restoration. Class V preparations were cut on extracted premolars and restored with amalgam, composite, or glass ionomer cement. Finishing was done with wet pumice and cup, wet pumice and a brush, a grit rubber polishing point, and an aluminum oxide- coated disc. Finishing time was continuous or intermittent for up to 1 minute. Dentin thickness under the restoration was 0.5 mm to 3.0 mm. Amalgam produced the highest temperature rises at the pulp, while composite and glass ionomer were no different than the untreated (virgin) tooth. Aluminum oxide discs produced the largest temperature rise, wet pumice with a brush the least. Temperature rise increased almost linearly with continuous finishing, while intermittent finishing significantly reduced temperature rise in all cases. Thickness of remaining dentin was only significant for the amalgam restoration, and then only at 1.0 and 0.5 mm.  相似文献   
45.

Objective  

To improve an existing measure of fruit and vegetable intake self efficacy by including items that varied on levels of difficulty, and testing a corresponding measure of water intake self efficacy.  相似文献   
46.
This second article in a four-part series provides a detailed discussion of each phase of the implementation process, along with a demographic summary of the University Hospital Patient Care Technicians' Program 2 years after program implementation. Part I provided the overview and conceptual framework for the model. Parts III and IV will present the results of a year-long evaluation of the model and the lessons learned during the implementation process.  相似文献   
47.
48.
Relations among academic achievement, school bonding, school misbehavior, and cigarette use from 8th to 12th grade were examined in two national panel samples of youth (n = 3056). A series of competing conceptual models developed a priori was tested using structural equation modeling (SEM). The findings suggest that during middle adolescence the predominant direction of influence is from school experiences to cigarette use. School misbehavior and low academic achievement contribute to increased cigarette use over time both directly and indirectly. Two-group SEM analyses involving two cohorts—gender and ethnicity—revealed that our findings are robust. In addition, comparisons between high school dropouts and nondropouts and between eighth-grade cigarette use initiators and nonusers revealed few differences in direction or magnitude of effects. Results suggest that prevention programs that attempt to reduce school misbehavior and academic failure, as well as to help students who misbehave and have difficulty in school constructively avoid negative school- and health-related outcomes, are likely to be effective in reducing adolescent cigarette use.  相似文献   
49.
This study, a focused community analysis, was conducted to determine the health needs and status of the aggregate of school-aged adolescents (13–18 years) using a method combining an epidemiologic approach with an ethnographic field method. Health was defined broadly, assumed to be interrelated with environmental, economic, social, educational, and cultural variables influencing adolescent life. The research involved five steps: collection of available secondary epidemiologic and census data; interviews with key informants, such as teachers, parents, school nurses, and other adults working with teenagers; participant observation and ethnographic interviews with primary informants, that is, teenagers from a variety of backgrounds; and finally, analysis and reporting of secondary and ethnographic data. Of the many themes generated in the data collection, four are reported here: lifestyle, health, pregnancy, and substance abuse. Findings included a typology of subgroups of the adolescent population that influenced lifestyles and led to different attitudes toward health, pregnancy, and substance abuse. The ethnographic approach facilitated an understanding of the health needs and attitudes of teenagers, implying a need for altered interventions and approaches by adults teaching and caring for them.  相似文献   
50.
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