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   413596篇
  免费   24791篇
  国内免费   493篇
耳鼻咽喉   5520篇
儿科学   13525篇
妇产科学   10902篇
基础医学   68079篇
口腔科学   11545篇
临床医学   35597篇
内科学   75108篇
皮肤病学   9701篇
神经病学   28919篇
特种医学   14683篇
外国民族医学   51篇
外科学   61762篇
综合类   6769篇
一般理论   83篇
预防医学   31218篇
眼科学   9694篇
药学   32383篇
  2篇
中国医学   781篇
肿瘤学   22558篇
  2018年   4060篇
  2016年   3308篇
  2015年   3603篇
  2014年   4912篇
  2013年   7615篇
  2012年   10355篇
  2011年   11473篇
  2010年   6693篇
  2009年   6184篇
  2008年   10866篇
  2007年   11795篇
  2006年   11936篇
  2005年   11476篇
  2004年   11133篇
  2003年   10764篇
  2002年   10594篇
  2001年   19226篇
  2000年   20112篇
  1999年   16405篇
  1998年   4369篇
  1997年   3738篇
  1996年   4020篇
  1995年   3689篇
  1994年   3472篇
  1992年   12689篇
  1991年   13027篇
  1990年   13091篇
  1989年   12705篇
  1988年   11636篇
  1987年   11500篇
  1986年   10915篇
  1985年   10306篇
  1984年   7617篇
  1983年   6604篇
  1982年   3666篇
  1981年   3366篇
  1979年   7497篇
  1978年   5472篇
  1977年   4630篇
  1976年   4457篇
  1975年   5079篇
  1974年   6078篇
  1973年   5751篇
  1972年   5577篇
  1971年   5367篇
  1970年   4931篇
  1969年   4699篇
  1968年   4502篇
  1967年   3971篇
  1966年   3565篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
Naunyn-Schmiedeberg's Archives of Pharmacology - Ochratoxin A (OTA) and aristolochic acid (AA) are toxins that can frequently contaminate cereals and cereals-based products. The present study...  相似文献   
24.

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   
25.
26.
27.
The interaction of trolox with ammonia, alkylamines of different classes, and amino derivatives of heterocyclic compounds, including nitroxyl radicals and alkaloids, led to the production of ammonium salts called ion conjugates (ICs). Five ICs were characterised by X-ray diffraction. This is the first time a wide range of ICs were made from trolox with amines, and ESI-MS data demonstrated they have the potential to generate pseudomolecular [(A?B+)?+?H]+ ions. For all obtained trolox ICs, a significant increase (1–3 orders of magnitude) in water solubility was achieved while retaining high antioxidant activity. ICs synthesised from two biologically active fragments may be used to create polyfunctional agents with varying solubility and bioavailability.  相似文献   
28.
29.
30.
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