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   2015篇
  免费   320篇
  国内免费   8篇
耳鼻咽喉   4篇
儿科学   103篇
妇产科学   284篇
基础医学   99篇
口腔科学   27篇
临床医学   866篇
内科学   226篇
皮肤病学   53篇
神经病学   37篇
特种医学   239篇
外科学   54篇
综合类   66篇
预防医学   126篇
眼科学   6篇
药学   67篇
肿瘤学   86篇
  2024年   4篇
  2023年   45篇
  2022年   7篇
  2021年   11篇
  2020年   37篇
  2019年   25篇
  2018年   63篇
  2017年   94篇
  2016年   80篇
  2015年   103篇
  2014年   107篇
  2013年   103篇
  2012年   65篇
  2011年   75篇
  2010年   106篇
  2009年   105篇
  2008年   53篇
  2007年   54篇
  2006年   48篇
  2005年   45篇
  2004年   27篇
  2003年   41篇
  2002年   28篇
  2001年   41篇
  2000年   21篇
  1999年   50篇
  1998年   96篇
  1997年   112篇
  1996年   111篇
  1995年   94篇
  1994年   64篇
  1993年   51篇
  1992年   29篇
  1991年   24篇
  1990年   15篇
  1989年   33篇
  1988年   33篇
  1987年   22篇
  1986年   28篇
  1985年   31篇
  1984年   14篇
  1983年   15篇
  1982年   20篇
  1981年   12篇
  1980年   17篇
  1979年   9篇
  1978年   17篇
  1977年   16篇
  1976年   13篇
  1975年   16篇
排序方式: 共有2343条查询结果,搜索用时 10 毫秒
81.
82.
83.
84.
85.

Background

Gloriosa superba produces an array of alkaloids including colchicine, a compound of interest in the treatment of various diseases. The tuber of Gloriosa superba is a rich source of colchicine which has shown anti-gout, anti-inflammatory, and anti-tumor activity. However, this promising compound remains expensive and Gloriosa superba is such a good source in global scale. Increase in yield of naturally occurring colchicine is an important area of investigation.

Materials and Methods

The effects of inoculation by four arbuscular mycorrhizal (AM), fungi, Glomus mossae, Glomus fasciculatum, Gigaspora margarita and Gigaspora gilmorei either alone or supplemented with P-fertilizer, on colchicine concentration in Gloriosa superba were studied. The concentration of colchicine was determined by high-performance thin layer chromatography.

Results

The four fungi significantly increased concentration of colchicine in the herb. Although there was significant increase in concentration of colchicine in non-mycorrhizal P-fertilized plants as compared to control, the extent of the increase was less compared to mycorrhizal plants grown with or without P-fertilization. This suggests that the increase in colchicine concentration may not be entirely attributed to enhanced P-nutrition and improved growth. Among the four AM fungi Glomus mossae was found to be best. The total colchicine content of plant (mg / plant) was significantly high in plants inoculated with Glomus mossae and 25 mg kg−1phosphorus fertilizer (348.9 mg /plant) while the control contain least colchicine (177.87 mg / plant).

Conclusion

The study suggests a potential role of AM fungi in improving the concentration of colchicine in Gloriosa superba tuber.  相似文献   
86.
87.
Nutrition management is a core component of intensive care medicine. Despite the increased use of non-invasive ventilation (NIV) for the critically ill, a paucity of evidence on nutrition management precludes recommendations for clinical practice. A scope of the available literature is required to guide future research on this topic. Database searches of MEDLINE, Embase, Scopus, Web of Science, and Google Scholar were conducted to identify original research articles and available grey literature in English from 1 January 1990 to 17 November 2021 that included adult patients (≥16 years) receiving NIV within an Intensive Care Unit. Data were extracted on: study design, aim, population, nutrition concept, context (ICU type, NIV: use, duration, interface), and outcomes. Of 1730 articles, 16 met eligibility criteria. Articles primarily included single-centre, prospective, observational studies with only 3 randomised controlled trials. Key concepts included route of nutrition (n = 7), nutrition intake (n = 4), energy expenditure (n = 2), nutrition status (n = 1), and nutrition screening (n = 1); 1 unpublished thesis incorporated multiple concepts. Few randomised clinical trials that quantify aspects of nutrition management for critically ill patients requiring NIV have been conducted. Further studies, particularly those focusing on the impact of nutrition during NIV on clinical outcomes, are required to inform clinical practice.  相似文献   
88.
89.
At the 2013 Academic Emergency Medicine global health consensus conference, a breakout session to develop a research agenda for resuscitation was held. Two articles are the result of that discussion. This second article addresses data collection, management, and analysis and regionalization of postresuscitation care, resuscitation programs, and research examples around the world and proposes a strategy to strengthen resuscitation research globally. There is a need for reliable global statistics on resuscitation, international standardization of data, and development of an electronic standard for reporting data. Regionalization of postresuscitation care is a priority area for future research. Large resuscitation clinical research networks are feasible and can give valuable data for improvement of service and outcomes. Low‐cost models of population‐based research, and emphasis on interventional and implementation studies that assess the clinical effects of programs and interventions, are needed to determine the most cost‐effective strategies to improve outcomes. The global challenge is how to adapt research findings to a developing world situation to have an effect internationally.  相似文献   
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