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   2614篇
  免费   151篇
  国内免费   5篇
耳鼻咽喉   14篇
儿科学   116篇
妇产科学   102篇
基础医学   371篇
口腔科学   73篇
临床医学   222篇
内科学   668篇
皮肤病学   29篇
神经病学   123篇
特种医学   466篇
外科学   178篇
综合类   53篇
预防医学   67篇
眼科学   148篇
药学   90篇
  1篇
肿瘤学   49篇
  2021年   23篇
  2020年   17篇
  2019年   22篇
  2018年   31篇
  2017年   24篇
  2016年   34篇
  2015年   41篇
  2014年   57篇
  2013年   76篇
  2012年   61篇
  2011年   82篇
  2010年   61篇
  2009年   73篇
  2008年   60篇
  2007年   84篇
  2006年   72篇
  2005年   80篇
  2004年   71篇
  2003年   66篇
  2002年   55篇
  2001年   64篇
  2000年   61篇
  1999年   48篇
  1998年   92篇
  1997年   97篇
  1996年   88篇
  1995年   74篇
  1994年   50篇
  1993年   77篇
  1992年   38篇
  1991年   42篇
  1990年   46篇
  1989年   78篇
  1988年   75篇
  1987年   65篇
  1986年   82篇
  1985年   90篇
  1984年   55篇
  1983年   48篇
  1982年   34篇
  1981年   39篇
  1980年   46篇
  1979年   18篇
  1978年   26篇
  1977年   34篇
  1976年   33篇
  1975年   32篇
  1974年   11篇
  1973年   10篇
  1969年   10篇
排序方式: 共有2770条查询结果,搜索用时 15 毫秒
51.
52.

OBJECTIVE

Gut microbiome dysbiosis is associated with numerous diseases, including type 1 diabetes. This pilot study determines how geographical location affects the microbiome of infants at high risk for type 1 diabetes in a population of homogenous HLA class II genotypes.

RESEARCH DESIGN AND METHODS

High-throughput 16S rRNA sequencing was performed on stool samples collected from 90 high-risk, nonautoimmune infants participating in The Environmental Determinants of Diabetes in the Young (TEDDY) study in the U.S., Germany, Sweden, and Finland.

RESULTS

Study site–specific patterns of gut colonization share characteristics across continents. Finland and Colorado have a significantly lower bacterial diversity, while Sweden and Washington state are dominated by Bifidobacterium in early life. Bacterial community diversity over time is significantly different by geographical location.

CONCLUSIONS

The microbiome of high-risk infants is associated with geographical location. Future studies aiming to identify the microbiome disease phenotype need to carefully consider the geographical origin of subjects.  相似文献   
53.
54.
55.
56.
The Dopamine Transporter (DAT) can reflect the general state of striatal dopamine activity. This current study examined the role of DAT in depressed patients before and after bupropion treatment. Twenty-three patients with major depression were treated with bupropion for 8 weeks. Before and after the treatment, they and 20 normal subjects received the radioligand 99mTc-TRODAT-1 single photon emission tomography scan (SPECT). Subjects were assessed with the Hamilton Depression Rating Scale. All DAT images were spatially normalized to an averaged brain template, and the specific binding ratios of the striatum, caudate, and putamen were calculated according the formulae of: [region counts] / [occipital counts] - 1. Depressed patients had greater DAT availability on both sides of the striatum. DAT binding was significantly decreased in the striatum after bupropion treatment. Women had higher initial and final DAT binding in the right and left caudate when compared to depressed men. DAT binding decreased in all areas of the brain in women after successful antidepressant treatment, but only in the right caudate of men. Depressed patients had a greater availability of DAT; it was decreased after bupropion treatment.Women seemed to have more DAT availability.  相似文献   
57.
Compromised health negatively impacts older persons’ ability to participate in expected social roles. Researchers have published little empirical work, however, to explore these issues in HIV endemic African settings. Qualitative interviews with 30 women, aged 60-plus, in rural South Africa, provide insight into the relationship between health and daily activities, with attention to the fulfillment of social roles. In this poor HIV endemic context, older women make connections between their compromised health and their (lack of) capacity to perform the daily tasks that they view as expected of them. By expanding the conceptualization of health to include the capacity to achieve the expectations and perform the tasks expected of one, we better understand how and why health and performance of daily activities are so intricately linked in the minds of respondents. This also provides a starting point for thinking about the social and structural support needed by older persons in these settings, especially as HIV erodes familial supports.  相似文献   
58.
59.
60.
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