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   513989篇
  免费   33465篇
  国内免费   614篇
耳鼻咽喉   6898篇
儿科学   16865篇
妇产科学   13522篇
基础医学   85032篇
口腔科学   14474篇
临床医学   44348篇
内科学   93654篇
皮肤病学   12156篇
神经病学   36192篇
特种医学   18455篇
外国民族医学   63篇
外科学   77044篇
综合类   8475篇
一般理论   119篇
预防医学   38973篇
眼科学   12134篇
药学   40538篇
中国医学   1006篇
肿瘤学   28120篇
  2018年   4931篇
  2015年   4509篇
  2014年   6059篇
  2013年   9546篇
  2012年   12866篇
  2011年   14269篇
  2010年   8299篇
  2009年   7772篇
  2008年   13693篇
  2007年   14698篇
  2006年   14938篇
  2005年   14353篇
  2004年   14046篇
  2003年   13387篇
  2002年   13267篇
  2001年   24067篇
  2000年   25080篇
  1999年   20557篇
  1998年   5427篇
  1997年   4705篇
  1996年   5042篇
  1995年   4625篇
  1994年   4318篇
  1993年   4135篇
  1992年   15726篇
  1991年   16310篇
  1990年   16423篇
  1989年   15800篇
  1988年   14578篇
  1987年   14420篇
  1986年   13597篇
  1985年   12975篇
  1984年   9627篇
  1983年   8247篇
  1982年   4559篇
  1981年   4230篇
  1979年   9418篇
  1978年   6860篇
  1977年   5773篇
  1976年   5604篇
  1975年   6397篇
  1974年   7635篇
  1973年   7133篇
  1972年   6961篇
  1971年   6686篇
  1970年   6176篇
  1969年   5890篇
  1968年   5560篇
  1967年   5013篇
  1966年   4452篇
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
31.
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   
32.
33.
34.

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   
35.
36.
37.
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   
38.
39.
40.
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