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   396篇
  免费   45篇
  2021年   4篇
  2018年   5篇
  2017年   8篇
  2016年   6篇
  2015年   12篇
  2014年   8篇
  2013年   44篇
  2012年   18篇
  2011年   20篇
  2010年   9篇
  2009年   17篇
  2008年   13篇
  2007年   10篇
  2006年   13篇
  2005年   18篇
  2004年   15篇
  2003年   7篇
  2002年   15篇
  2001年   14篇
  2000年   7篇
  1999年   10篇
  1998年   4篇
  1997年   6篇
  1996年   5篇
  1994年   3篇
  1992年   3篇
  1991年   3篇
  1990年   6篇
  1989年   7篇
  1988年   3篇
  1987年   6篇
  1986年   5篇
  1985年   4篇
  1982年   4篇
  1979年   5篇
  1978年   3篇
  1977年   3篇
  1975年   4篇
  1973年   4篇
  1971年   3篇
  1970年   3篇
  1968年   3篇
  1965年   4篇
  1963年   4篇
  1883年   3篇
  1882年   5篇
  1881年   2篇
  1879年   6篇
  1878年   2篇
  1877年   2篇
排序方式: 共有441条查询结果,搜索用时 198 毫秒
1.
Stairway climbing provides a ubiquitous and inconspicuous method of burning calories. While typically two strategies are employed for climbing stairs, climbing one stair step per stride or two steps per stride, research to date has not clarified if there are any differences in energy expenditure between them. Fourteen participants took part in two stair climbing trials whereby measures of heart rate were used to estimate energy expenditure during stairway ascent at speeds chosen by the participants. The relationship between rate of oxygen consumption () and heart rate was calibrated for each participant using an inclined treadmill. The trials involved climbing up and down a 14.05 m high stairway, either ascending one step per stride or ascending two stair steps per stride. Single-step climbing used 8.5±0.1 kcal min−1, whereas double step climbing used 9.2±0.1 kcal min−1. These estimations are similar to equivalent measures in all previous studies, which have all directly measured The present study findings indicate that (1) treadmill-calibrated heart rate recordings can be used as a valid alternative to respirometry to ascertain rate of energy expenditure during stair climbing; (2) two step climbing invokes a higher rate of energy expenditure; however, one step climbing is energetically more expensive in total over the entirety of a stairway. Therefore to expend the maximum number of calories when climbing a set of stairs the single-step strategy is better.  相似文献   
2.
A case of renal-cell carcinoma metastatic to both adrenals and presenting 19 years following removal of the primary tumor was diagnosed by fine needle aspiration and confirmed by histopathologic study. The differential diagnosis is discussed, and the importance of the knowledge of tumor size, hormonal function and disease presentation when interpreting adrenal aspirates is stressed.  相似文献   
3.
4.
5.
In this article the conditions that govern surfactant‐enhanced emulsification and mobilization of petroleum hydrocarbons in soil are reviewed. The effect of soil properties, groundwater constituents, and differing surfactant solutions on the emulsification process is discussed. A constant head soil flushing apparatus used to characterize surfactant‐enhanced mobilization of m‐xylene is described. Data showing the effect of surfactant‐enhanced mobilization on m‐xylene removal efficiency in washed sand is presented. Flushing solutions were used at concentrations from below to well above the critical micelle concentration (CMC) of the surfactants used. Removal efficiencies are shown to vary with surfactant concentration and with surfactant type. Flushing solutions of anionic, nonionic, and anionic/nonionic surfactant mixtures were evaluated.  相似文献   
6.
7.
8.
9.
10.
Candida albicans and Candida glabrata account for the majority of candidiasis cases worldwide. Although both species are in the same genus, they differ in key virulence attributes. Within this work, live cell imaging was used to examine the dynamics of neutrophil activation after confrontation with either C. albicans or C. glabrata. Analyses revealed higher phagocytosis rates of C. albicans than C. glabrata that resulted in stronger PMN (polymorphonuclear cells) activation by C. albicans. Furthermore, we observed differences in the secretion of chemokines, indicating chemotactic differences in PMN signalling towards recruitment of further immune cells upon confrontation with Candida spp. Supernatants from co‐incubations of neutrophils with C. glabrata primarily attracted monocytes and increased the phagocytosis of C. glabrata by monocytes. In contrast, PMN activation by C. albicans resulted in recruitment of more neutrophils. Two complex infection models confirmed distinct targeting of immune cell populations by the two Candida spp.: In a human whole blood infection model, C. glabrata was more effectively taken up by monocytes than C. albicans and histopathological analyses of murine model infections confirmed primarily monocytic infiltrates in C. glabrata kidney infection in contrast to PMN‐dominated infiltrates in C. albicans infection. Taken together, our data demonstrate that the human opportunistic fungi C. albicans and C. glabrata are differentially recognized by neutrophils and one outcome of this differential recognition is the preferential uptake of C. glabrata by monocytes.  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