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   3114137篇
  免费   199701篇
  国内免费   4341篇
耳鼻咽喉   43482篇
儿科学   100318篇
妇产科学   83184篇
基础医学   451451篇
口腔科学   85933篇
临床医学   279322篇
内科学   593258篇
皮肤病学   68860篇
神经病学   241890篇
特种医学   117549篇
外国民族医学   676篇
外科学   465055篇
综合类   63142篇
现状与发展   13篇
一般理论   1049篇
预防医学   236231篇
眼科学   72436篇
药学   235940篇
  79篇
中国医学   6550篇
肿瘤学   171761篇
  2021年   24589篇
  2019年   25500篇
  2018年   34240篇
  2017年   26152篇
  2016年   29458篇
  2015年   32969篇
  2014年   46178篇
  2013年   69104篇
  2012年   94922篇
  2011年   101026篇
  2010年   60016篇
  2009年   56473篇
  2008年   94559篇
  2007年   100959篇
  2006年   101862篇
  2005年   98518篇
  2004年   94332篇
  2003年   90949篇
  2002年   87977篇
  2001年   145922篇
  2000年   150081篇
  1999年   125940篇
  1998年   35457篇
  1997年   31172篇
  1996年   31467篇
  1995年   29590篇
  1994年   27226篇
  1993年   25673篇
  1992年   96973篇
  1991年   94299篇
  1990年   92436篇
  1989年   88939篇
  1988年   81529篇
  1987年   79935篇
  1986年   75041篇
  1985年   71535篇
  1984年   52936篇
  1983年   44982篇
  1982年   26250篇
  1979年   48441篇
  1978年   34072篇
  1977年   28976篇
  1976年   26994篇
  1975年   29530篇
  1974年   35029篇
  1973年   33518篇
  1972年   31691篇
  1971年   29945篇
  1970年   27596篇
  1969年   26414篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
101.
102.
103.
104.
105.
106.
107.
108.
109.

Background

Few U.S. studies have explored how children experience a parent's mobility disability and its effects on their daily lives.

Objective

We aimed to engage youth ages 13–17 who had at least one parent with mobility disability in describing their perceptions of their parent's disability and its consequences for their daily and family life.

Methods

Participants videoed and photographed their experiences following general guidelines from the researchers about topics of interest. Participants made their own choices about what they submitted. We used conventional content analysis to identify broad themes.

Results

The mean (standard deviation) age of the 10 participants was 15.2 (1.9) years; 5 were male; 9 participants were white. All 5 girls submitted multiple self-focused (selfie) videos made in their bedrooms; the 5 boys submitted more diverse data files. Several broad themes or topics emerged including: the effects of timing and trajectory of the parent's disability; perceptions of early maturity and responsibility; fears and frustrations relating to the parent's disability; support and emerging resilience; and sense of social justice. Participants generally felt their parents' disability made them become – compared to their peers – more mature, responsible, capable of performing household tasks, and aware of disability civil rights.

Conclusions

Participants raised many issues that health care providers should be aware of when youth have parents with mobility disability. A parent's mobility disability may be associated with resilience but also may pose challenges for youth. More research is needed to understand better adolescents' experiences and how clinicians might best assist these youth.  相似文献   
110.

Background

Little is known about zinc intakes and status during complementary feeding. This is particularly true for baby-led approaches, which encourage infants to feed themselves from the start of complementary feeding, although self-feeding may restrict the intake of zinc-rich foods.

Objective

To determine the zinc intakes, sources, and biochemical zinc status of infants following Baby-Led Introduction to SolidS (BLISS), a modified version of Baby-Led Weaning (BLW), compared with traditional spoon-feeding.

Design

Secondary analysis of the BLISS randomized controlled trial.

Participants/setting

Between 2012 and 2014, 206 community-based participants from Dunedin, New Zealand were randomized to a Control or BLISS group.

Intervention

BLISS participants received eight study visits (antenatal to 9 months) providing education and support regarding BLISS (ie, infant self-feeding from 6 months with modifications to address concerns about iron, choking, and growth).

Main outcome measures

Dietary zinc intakes at 7 and 12 months (weighed 3-day diet records) and zinc status at 12 months (plasma zinc concentration).

Statistical analyses performed

Regression analyses were used to investigate differences in dietary intakes and zinc status by group, adjusted for maternal education and parity and infant age and sex.

Results

There were no significant differences in zinc intakes between BLISS and Control infants at 7 (median: 3.5 vs 3.5 mg/day; P=0.42) or 12 (4.4 vs 4.4 mg/day; P=0.86) months. Complementary food groups contributing the most zinc at 7 months were “vegetables” for Control infants, and “breads and cereals” for BLISS infants, then “dairy” for both groups at 12 months. There was no significant difference in mean±standard deviation plasma zinc concentration between the Control (62.8±9.8 μg/dL [9.6±1.5 μmol/L]) and BLISS (62.8±10.5 μg/dL [9.6±1.6 μmol/L]) groups (P=0.75).

Conclusions

BLISS infants achieved similar zinc intake and status to Control infants. However, the BLISS intervention was modified to increase iron intake, which may have improved zinc intake, so these results should not be generalized to infants following unmodified BLW.  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