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   6485篇
  免费   394篇
  国内免费   41篇
耳鼻咽喉   10篇
儿科学   224篇
妇产科学   37篇
基础医学   870篇
口腔科学   67篇
临床医学   318篇
内科学   656篇
皮肤病学   10篇
神经病学   575篇
特种医学   68篇
外科学   244篇
综合类   233篇
预防医学   2584篇
眼科学   9篇
药学   801篇
中国医学   64篇
肿瘤学   150篇
  2023年   86篇
  2022年   281篇
  2021年   445篇
  2020年   243篇
  2019年   244篇
  2018年   198篇
  2017年   164篇
  2016年   178篇
  2015年   223篇
  2014年   328篇
  2013年   562篇
  2012年   241篇
  2011年   344篇
  2010年   239篇
  2009年   265篇
  2008年   264篇
  2007年   213篇
  2006年   194篇
  2005年   154篇
  2004年   155篇
  2003年   133篇
  2002年   100篇
  2001年   89篇
  2000年   82篇
  1999年   72篇
  1998年   75篇
  1997年   70篇
  1996年   53篇
  1995年   63篇
  1994年   36篇
  1993年   38篇
  1992年   58篇
  1991年   58篇
  1990年   51篇
  1989年   43篇
  1988年   59篇
  1987年   34篇
  1986年   26篇
  1985年   88篇
  1984年   92篇
  1983年   67篇
  1982年   77篇
  1981年   57篇
  1980年   71篇
  1979年   63篇
  1978年   51篇
  1977年   41篇
  1976年   42篇
  1975年   39篇
  1974年   27篇
排序方式: 共有6920条查询结果,搜索用时 825 毫秒
1.
2.
3.
The regulation of food intake is a complex mechanism, and the hypothalamus is the main central structure implicated. In particular, the arcuate nucleus appears to be the most critical area in the integration of multiple peripheral signals.Among these signals, those originating from the white adipose tissue and the gastrointestinal tract are known to be involved in the regulation of food intake.The present paper focuses on adiponectin, an adipokine secreted by white adipose tissue, which is reported to have a role in the control of feeding by acting centrally. The recent observation that adiponectin is also able to influence gastric motility raises the question of whether this action represents an additional peripheral mechanism that concurs with the central effects of the hormone on food intake. This possibility, which represents an emerging aspect correlating the central and peripheral effects of adiponectin in the hunger-satiety cycle, is discussed in the present paper.  相似文献   
4.
BackgroundTheoretical models argue that coping reduces stress responses, yet no studies have tested whether coping moderates the prospective stress effects on sleep in daily life.PurposeThis study tested if coping moderates the stress-sleep association using a daily, intensive longitudinal design across 7–12 days.Methods326 young adults (Mage = 23.24 ± 5.46) reported perceived stress and coping (problem-focused, emotional-approach, and avoidance) every evening between 20:00–02:00, providing over 2400 nights of sleep data and 3000 stress surveys from all participants. Actigraphy and sleep diaries measured total-sleep-time and sleep efficiency. Multilevel models tested the interaction effects of within- and between-person stress and coping on sleep.ResultsWithin-person problem-focused and emotional-approach coping moderated the within-person stress effects on actigraphic total-sleep-time (both p = 0.02); higher stress predicted shorter total-sleep-time only during high use of problem-focused or emotional-approach coping (both p = 0.01). Between-person avoidance moderated the between-person stress effect on actigraphic total-sleep-time (p = 0.04); higher stress predicted shorter total-sleep-time for high avoidance coping (p = 0.02). Within-person emotional-approach coping buffered the between-person stress effect on actigraphic sleep efficiency (p = 0.02); higher stress predicted higher sleep efficiency for high emotional-approach coping (p = 0.04).ConclusionsThis study showed that daily coping moderates the effects of evening stress on sleep that night. More efforts to cope with stress before bedtime had a short-term cost of shorter sleep that night. However, high use of emotional-approach coping buffered the impact of stress to promote sleep efficiency.  相似文献   
5.
6.
BackgroundLittle is known about breakfast habits of the Latin American (LA) population to support nutritional recommendations for a balanced breakfast in this region.ObjectiveTo evaluate the nutritional composition of breakfast in the LA population and to propose recommendations for a balanced breakfast.DesignThis multicenter cross-sectional study evaluated food and nutrient intake of nationally representative samples of urban populations of 8 LA countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru, and Venezuela) in 2014-2015.Participants/settingThe sample comprised 8714 participants from the Latin American Study of Nutrition and Health, aged 15 to 65 years, randomly recruited according to geographical location, sex, age, and socioeconomic level.Main outcome measuresTwo 24-hour recalls were used to examine dietary intake. Breakfast consumers were stratified by tertiles of Nutrient-Rich Foods Index 9.3 (NRF9.3) to assess the overall diet quality of individuals. Nutrient intake at breakfast of those in the upper tertile of NRF9.3 pooled for the 8 countries was used as a reference for the development of recommendations for LA adolescents and adults.Statistical analysesComparison of food and nutrient intake of breakfast across NRF9.3 tertiles were analyzed using the Kruskal-Wallis rank sum test.ResultsOverall breakfast was an important contributor to protein, carbohydrate, and B vitamin intakes but also to added sugar and total and saturated fat intakes relative to daily intakes. Individuals in the upper NRF9.3 tertile had higher intake of key micronutrients such as calcium and potassium at breakfast compared with other tertiles. White breads/rolls/tortillas were the most consumed food group (60%), followed by butter/margarine (40%) and coffee/tea without milk (34%-50%).ConclusionsBreakfast contributed to the daily intake of B vitamins, protein, and carbohydrates but also added sugar and total and saturated fat intakes for all countries. The proposed recommendations support the nutrient density of existing highest-quality breakfast in the LA population while addressing concerns about nutrients to be encouraged or reduced.  相似文献   
7.
8.
9.
10.
Twenty-eight members of the general public, with little nutritional knowledge and no previous commitment to dietary change, completed 7-day-weighed dietary diaries. They then attempted to change their diets, where appropriate, in line with current nutritional guidelines.
The panel achieved changes in diet that were consistent with the recent recommendations but several problems arose. In particular, although fat levels were reduced, energy levels fell and fibre goals were not reached; in addition, certain of the initial vitamin and mineral intakes gave cause for concern. These results emphasize the importance of giving advice not only about foods that might be reduced in the diet, but also about food that might be used as alternatives. They also illustrate the difficulty of persuading people to make radical changes to their eating habits even when given personal advice from a nutritionist.
The panel was small and not necessarily representative, but the results illustrate the need for more dietary analysis studies. It is not enough simply to formulate appropriate guidelines from a nutritional point of view; it is also important to ensure that the public understands them and that people make sensible decisions about their diet.  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