收费全文 | 18354篇 |
免费 | 2589篇 |
国内免费 | 403篇 |
医药卫生 | 21346篇 |
2024年 | 55篇 |
2023年 | 433篇 |
2022年 | 243篇 |
2021年 | 448篇 |
2020年 | 429篇 |
2019年 | 205篇 |
2018年 | 764篇 |
2017年 | 759篇 |
2016年 | 817篇 |
2015年 | 787篇 |
2014年 | 726篇 |
2013年 | 998篇 |
2012年 | 1037篇 |
2011年 | 1142篇 |
2010年 | 954篇 |
2009年 | 956篇 |
2008年 | 852篇 |
2007年 | 842篇 |
2006年 | 650篇 |
2005年 | 822篇 |
2004年 | 1507篇 |
2003年 | 1254篇 |
2002年 | 944篇 |
2001年 | 826篇 |
2000年 | 354篇 |
1999年 | 458篇 |
1998年 | 399篇 |
1997年 | 330篇 |
1996年 | 155篇 |
1995年 | 114篇 |
1994年 | 101篇 |
1993年 | 120篇 |
1992年 | 101篇 |
1991年 | 56篇 |
1990年 | 65篇 |
1989年 | 65篇 |
1988年 | 58篇 |
1987年 | 50篇 |
1986年 | 46篇 |
1985年 | 24篇 |
1984年 | 21篇 |
1983年 | 21篇 |
1982年 | 21篇 |
1981年 | 22篇 |
1980年 | 16篇 |
1977年 | 14篇 |
1975年 | 14篇 |
1974年 | 19篇 |
1968年 | 17篇 |
1928年 | 13篇 |
Methods and Results: Based on real expenditure data from 2002 to 2005, as recorded in the Search-MI Registry-Italian Sub-study of patients implanted on MADIT II indications, we estimated the daily costs associated with the device and leads. Over a 5–7 year time horizon, the average daily cost was estimated to be €4.60–€6.70. Translation of these figures into U.S. market conditions suggests a daily cost of around $7.90–$11.40.
Conclusions: These findings appear useful to help evaluate the affordability of ICD in comparison with other therapeutic options in a context of limited available economic resources. 相似文献
Methods: An experimental bronchopneumonia was induced in anesthetized piglets by inoculating lower lobes with a suspension of 106 cfu/ml Escherichia coli. After 24 h of mechanical ventilation, 7 animals received two intravenous injections of 15 mg/kg amikacin, and 11 animals received two nebulizations of 40 mg/kg amikacin at 24-h intervals. One hour following the second administration, animals were killed, and multiple lung specimens were sampled for assessing amikacin pulmonary concentrations and quantifying lung aeration on histologic sections.
Results: Thirty-eight percent of the nebulized amikacin (15 mg/kg) reached the tracheobronchial tree. Amikacin pulmonary concentrations were always higher after nebulization than after intravenous administration, decreased with the extension of parenchymal infection, and were significantly influenced by lung aeration: 197 +/- 165 versus 6 +/- 5 [mu]g/g in lung segments with focal bronchopneumonia (P = 0.03), 40 +/- 62 versus 5 +/- 3 [mu]g/g in lung segments with confluent bronchopneumonia (P = 0.001), 18 +/- 7 versus 7 +/- 4 [mu]g/g in lung segments with lung aeration of 30% or less, and 65 +/- 9 versus 2 +/- 3 [mu]g/g in lung segments with lung aeration of 50% or more. 相似文献