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   21342篇
  免费   5660篇
  国内免费   127篇
耳鼻咽喉   642篇
儿科学   616篇
妇产科学   690篇
基础医学   308篇
口腔科学   2695篇
临床医学   4146篇
内科学   5031篇
皮肤病学   473篇
神经病学   1839篇
特种医学   1004篇
外科学   3817篇
综合类   55篇
现状与发展   12篇
预防医学   2694篇
眼科学   322篇
药学   190篇
中国医学   6篇
肿瘤学   2589篇
  2024年   163篇
  2023年   1090篇
  2022年   354篇
  2021年   633篇
  2020年   1212篇
  2019年   476篇
  2018年   1320篇
  2017年   1280篇
  2016年   1500篇
  2015年   1558篇
  2014年   1961篇
  2013年   2364篇
  2012年   758篇
  2011年   726篇
  2010年   1352篇
  2009年   1940篇
  2008年   736篇
  2007年   488篇
  2006年   638篇
  2005年   448篇
  2004年   324篇
  2003年   289篇
  2002年   251篇
  2001年   383篇
  2000年   286篇
  1999年   383篇
  1998年   508篇
  1997年   487篇
  1996年   535篇
  1995年   387篇
  1994年   299篇
  1993年   259篇
  1992年   176篇
  1991年   156篇
  1990年   144篇
  1989年   144篇
  1988年   128篇
  1987年   127篇
  1986年   106篇
  1985年   100篇
  1984年   84篇
  1983年   94篇
  1982年   83篇
  1981年   70篇
  1980年   46篇
  1979年   37篇
  1978年   33篇
  1977年   44篇
  1976年   31篇
  1975年   27篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Phonetics, esthetics, function, and comfort form the foundation of a successful dental prosthesis. A review of the mechanics of speech as well as common speech problems encountered with a removable maxillary prosthesis are presented. The use of a palatogram to aid the clinician in the assessment and resolution of speech problems associated with a maxillary denture is demonstrated.  相似文献   
42.
43.
44.
45.
46.
47.
48.
49.
Advancing age is associated with a remarkable number of changes in body composition, including reduction in lean body mass and increase in body fat, which have been well documented. Decreased lean body mass occurs primarily as a result of losses in skeletal muscle mass. This age-related loss in muscle mass has been termed “sarcopenia”. Loss in muscle mass accounts for the age-associated decreases in basal metabolic rate, muscle strength, and activity levels, which, in turn are the cause of the decreased energy requirements of the elderly. In sedentary persons, the main determinant of energy expenditure is fat-free mass, which declines by about 15% between the third and eighth decade of life. It also appears that declining energy needs are not matched by an appropriate decline in energy intake, with the ultimate result being increased body fat content. Increased body fatness and increased abdominal obesity are thought to be directly linked to the greatly increased incidence of non-insulin-dependent diabetes mellitus among the elderly. In this review we will discuss the extent to which regularly performed exercise can affect nutrition needs and functional capacity in the elderly. We will also discuss a variety of concerns when prescribing exercise in the elderly, such as planning for a wide variability in functional status, medical status, and training intensity and duration. Finally, we will attempt to provide some basic guidelines for beginning an exercise program for older men and women and establishing community-based programs.  相似文献   
50.
Objective To ascertain the association between diet composition and body fat percentage in 9- and 10-year-old children. Also, to examine the influence of gender, total energy intake, fitness, physical activity, and parental body mass on the relationship between diet composition and adiposity.Design Diet composition was assessed using the National Cancer Institute food frequency questionnaire, and adiposity was measured using the average of results determined using two skinfold equations. Fitness levels and physical activity were ascertained using the 1-mile run/walk test and a self-report 15-item scale, respectively.Subjects A sample of 262 children (162 boys and 100 girls, mean age=9.8±0.5 years) participated.Statistical analysis Regression analysis was used to determine the extent to which diet composition contributed to adiposity without statistical control for any potentially confounding variables. Partial correlations were calculated to assess the relationship between macronutrient intake and adiposity after potential confounders (gender, total energy intake, physical fitness, and parental body mass) were controlled statistically.Results Energy intake was positively related to adiposity. Fat intake, calculated as a percentage of total energy, was also positively related to adiposity, before and after control for potential confounding variables. Percentage of energy derived from carbohydrate was inversely related to adiposity, before and after controlling for potential confounders.Applications These findings indicate that the macronutrient intake of children, particularly dietary fat and carbohydrate intake, may play a role in adiposity, independent of the influence of total energy intake, gender, physical fitness, and parental body mass index.  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