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   61篇
  免费   2篇
林业   1篇
基础科学   1篇
  9篇
综合类   29篇
水产渔业   7篇
畜牧兽医   15篇
园艺   1篇
  2023年   1篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   1篇
  2014年   2篇
  2011年   2篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2005年   1篇
  2004年   4篇
  2003年   1篇
  2002年   4篇
  2000年   2篇
  1999年   1篇
  1997年   1篇
  1995年   4篇
  1990年   3篇
  1989年   1篇
  1985年   2篇
  1982年   1篇
  1981年   1篇
  1973年   2篇
  1969年   1篇
  1968年   1篇
  1919年   1篇
  1913年   2篇
  1903年   1篇
  1901年   1篇
  1898年   1篇
  1896年   1篇
  1892年   1篇
  1891年   1篇
  1887年   1篇
  1884年   2篇
  1883年   8篇
  1881年   1篇
排序方式: 共有63条查询结果,搜索用时 328 毫秒
41.
42.
43.
44.
OBJECTIVES: To compare dietary intake and sources of phylloquinone (vitamin K1) in 4-year-old British children between 1950 and the 1990s, and report their variation by sociodemographic factors.Design: Nationally representative samples of 4-year-olds from the longitudinal Medical Research Council National Survey of Health and Development (NSHD) (1950) and the cross-sectional National Diet and Nutrition Surveys (NDNS, 1992/93 and 1997). SETTING: Great Britain. SUBJECTS: Subjects were 4599 children born on 3-9 March 1946 (NSHD) and 307 children in the 1990s (NDNS). RESULTS: Geometric mean dietary phylloquinone intake was significantly higher in 1950 (39 mug day(-1), 95% confidence interval (CI) 37, 40) compared with the 1990s (24 mug day(-1), 95% CI 22, 25) (P<0.001). This difference remained when intake was expressed per MJ energy intake and per kilogram body weight, and after accounting for sex, region and occupational social class of the family. In 1950, phylloquinone intake in Scotland was significantly lower than in the rest of Britain. By the 1990s these regional differences had disappeared. Food sources of phylloquinone intake changed significantly between 1950 and the 1990s, with fats and oils contributing more and vegetables less, although vegetables contributed most (60% and 48%, respectively) to phylloquinone intake in both surveys. CONCLUSIONS: Phylloquinone intakes of children have decreased significantly since 1950. With the suggested need for adequate phylloquinone intake for optimal development and maintenance of bone and the cardiovascular system, the substantially lower phylloquinone intakes reported in children of the 1990s, compared with 1950, may have implications for the health of these two systems in later adulthood.  相似文献   
45.
46.
47.
48.
49.

Objective

To determine the agreement of invasive blood pressure measured in the facial, metatarsal and carotid arteries, and evaluate the effects of two haemodynamic conditions on agreement.

Study design

Prospective randomized study.

Animals

A group of eight horses aged 7 (4–23) years with a body weight of 493 ± 33 kg.

Methods

Horses were anaesthetized and positioned in dorsal recumbency. Invasive blood pressure was measured simultaneously via catheters placed in the facial, metatarsal and carotid arteries. Cardiovascular function and agreement between arteries was assessed before and during administration of phenylephrine and sodium nitroprusside. These were administered until carotid mean pressure (MAPc) increased or decreased from baseline (65 ± 5) to >90 or <50 mmHg, respectively. Data recorded at each sample time included systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures for carotid (c), facial (f) and metatarsal (m) arteries as well as cardiac output (Q˙t) and systemic vascular resistance (SVR). Bland–Altman analysis was used to assess agreement between peripheral and central sites, and regression analysis to determine influence of Q˙t and SVR.

Results

The largest difference was observed in SAPc and SAPm with a bias and limits of agreement (LOA) of 2 (?15 to 19) mmHg. The bias (LOA) for MAPc and MAPf was 2 (?4 to 9) mmHg and for MAPc and MAPm was 5 (?4 to 14) mmHg. The best agreement for DAP was seen between DAPc and DAPf with bias (LOA) of 1 (?3 to 5) mmHg. Regression analysis indicated marginal influence on agreement by Q˙t on MAPc and MAPf.

Conclusions and clinical relevance

MAP and DAP of the carotid artery were higher than those of the peripheral arteries, which may lead to overzealous treatment of hypotension, albeit maintaining central pressures. Q˙t and SVR did not largely influence the difference between sites.  相似文献   
50.
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