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   12058篇
  免费   9篇
教育   9240篇
科学研究   1248篇
各国文化   5篇
体育   449篇
文化理论   384篇
信息传播   741篇
  2023年   7篇
  2022年   3篇
  2021年   3篇
  2020年   10篇
  2019年   26篇
  2018年   2191篇
  2017年   2103篇
  2016年   1580篇
  2015年   125篇
  2014年   140篇
  2013年   236篇
  2012年   231篇
  2011年   705篇
  2010年   844篇
  2009年   440篇
  2008年   658篇
  2007年   1160篇
  2006年   83篇
  2005年   401篇
  2004年   453篇
  2003年   366篇
  2002年   135篇
  2001年   9篇
  2000年   22篇
  1999年   11篇
  1998年   5篇
  1997年   20篇
  1996年   5篇
  1995年   4篇
  1994年   5篇
  1993年   6篇
  1992年   7篇
  1991年   14篇
  1990年   13篇
  1989年   5篇
  1988年   2篇
  1983年   3篇
  1982年   2篇
  1980年   2篇
  1979年   2篇
  1977年   3篇
  1976年   5篇
  1973年   5篇
  1972年   2篇
  1970年   2篇
  1969年   1篇
  1966年   1篇
  1963年   1篇
  1960年   1篇
  1880年   1篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
82.
83.
84.
85.
86.
Abstract

Maternal dietary habits influence maternal and foetal health, representing a pathway for intervention to maximise pregnancy outcomes. Advice on energy intake is provided on a trimester basis, with no additional calories required in the first trimester and an additional 340?kcal?d?1 and 452?kcal?d?1 needed for the second and third trimesters. Energy intake depends on pre-gravid body mass index (BMI); underweight women are recommended an increase of 150, 200 and 300?kcal?d?1 during the first, second and third trimester, normal weight women an increase of 0, 350 and 500?kcal?d?1 and obese women an increase of 0, 450 and 350?kcal?day?1. The recommendations for carbohydrate and protein intake are 175?g?d?1 and 0.88–1.1?g?kgBM?d?1, with no change to fat intake. The number of pre-gravid obese women is rising; therefore, we need to regulate weight in women of childbearing age and limit gestational weight gain to within the recommended ranges [overweight women 6.8–11.3?kg and obese women 5.0–9.1?kg]. This can be achieved using nutritional interventions, as dietary changes have been shown to help with gestational weight management. As pregnancy has been identified as a risk factor for the development of obesity, normal weight women should gain 11.5–16.0?kg during pregnancy. While some research has shown that dietary interventions help to regulate gestational weight gain and promote postpartum weight loss to some extent, future research is needed to provide safe and effective guidelines to maximise these effects, while benefitting maternal and foetal health.  相似文献   
87.
88.
ABSTRACT

With increasing demand for improved medical equipment and healthcare, next-generation biomedical engineers need strong design skills. Equipping biomedical engineering students with tools for idea generation and development can increase student design success. Design Heuristics are an ideation tool developed through empirical studies of product designs. While identified in the mechanical engineering space, Design Heuristics may be applicable in biomedical engineering design. In our study, we implemented a Design Heuristics session during upper-level undergraduate and first-year graduate biomedical engineering design courses. We examined the applicability of Design Heuristics within individual and team concept generation contexts. The findings demonstrated that biomedical engineering students were able to use Design Heuristics to generate multiple concepts, and that initial concepts produced using Design Heuristics were carried over into final team design. The results support the applicability of Design Heuristics to student idea generation in biomedical engineering design.  相似文献   
89.
90.
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