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   4956篇
  免费   274篇
  国内免费   23篇
耳鼻咽喉   52篇
儿科学   65篇
妇产科学   68篇
基础医学   873篇
口腔科学   182篇
临床医学   409篇
内科学   1143篇
皮肤病学   112篇
神经病学   354篇
特种医学   203篇
外科学   745篇
综合类   22篇
预防医学   226篇
眼科学   64篇
药学   369篇
中国医学   6篇
肿瘤学   360篇
  2023年   26篇
  2022年   53篇
  2021年   106篇
  2020年   79篇
  2019年   99篇
  2018年   96篇
  2017年   80篇
  2016年   105篇
  2015年   122篇
  2014年   146篇
  2013年   202篇
  2012年   336篇
  2011年   372篇
  2010年   220篇
  2009年   208篇
  2008年   304篇
  2007年   338篇
  2006年   335篇
  2005年   308篇
  2004年   263篇
  2003年   265篇
  2002年   232篇
  2001年   84篇
  2000年   62篇
  1999年   71篇
  1998年   55篇
  1997年   50篇
  1996年   37篇
  1995年   31篇
  1994年   23篇
  1993年   28篇
  1992年   40篇
  1991年   39篇
  1990年   28篇
  1989年   24篇
  1988年   30篇
  1987年   18篇
  1986年   18篇
  1985年   24篇
  1984年   16篇
  1983年   16篇
  1982年   13篇
  1981年   13篇
  1980年   12篇
  1979年   20篇
  1978年   26篇
  1977年   16篇
  1974年   11篇
  1973年   10篇
  1971年   10篇
排序方式: 共有5253条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.

Hintergrund:  

Die nosokomiale Pneumonie gehört zu den häufigsten nosokomialen Infektionen und ist die häufigste auf der Intensivstation. Die nosokomiale Pneumonie ist mit einer signifikanten Mortalität und Morbidität assoziiert, und ihr Auftreten verschlechtert die Prognose des Patienten deutlich. Nach der Definition der DRGs auch im deutschen Krankenhaussystem ist die nosokomiale Pneumonie überwiegend Sache des Krankenhauses und kann somit nicht nur das Ergebnis der Patientenbehandlung, sondern auch das finanzielle Ergebnis des Krankenhauses beeinträchtigen.  相似文献   
5.
It obviously escaped the notion of Egeland and Brinchman thatthe protocols additionally differ with regard to the washingsteps and buffer components used in the  相似文献   
6.
Based on the hypothesis that condensation products of neurotransmitters with aldehydes are involved in the pathogenesis of alcoholism, aromatic beta-carbolines (norharman and harman) were measured in the blood plasma of alcoholics and nonalcoholics. The identity of the extracted compounds was confirmed by various elution conditions of the high performance liquid chromatography (HPLC), newly developed radioreceptor assays, and the mass spectrum of norharman. The levels of norharman and harman in nonalcoholics were unchanged after a load with ethanol (1 g/kg body weight). The norharman levels of the alcoholics were significantly higher than that of the nonalcoholic controls (99.5 +/- 26.6 pg/ml vs. 26.9 +/- 10.7 pg/ml; p less than 0.001) and did not change significantly during a 3-week detoxication period. In the subgroup of alcoholics with delirium or hallucinosis, a slight increase of norharman during detoxication could be detected while in alcoholics with vegetative withdrawal symptoms norharman levels dropped slightly over time (p = 0.07). No difference was found with respect to harman between nonalcoholics and alcoholics. These results suggest disturbed regulatory processes in the formation and/or metabolism of norharman in alcoholics. Further investigations are needed to reveal a possible marker function of norharman in alcoholic patients.  相似文献   
7.
8.
The disposition of 4'-hydroxypropranolol (HOP) was determined after iv administration to dogs (2 mg/kg; N = 5) and the pharmacokinetic parameters were calculated from plasma measurements. The clearance of HOP, 66 +/- 6 ml/min/kg (mean +/- SE), was considerably higher than that of propranolol previously determined, suggesting extrahepatic as well as hepatic clearance of HOP. The plasma half-life of HOP, 77 +/- 6 min, was shorter than that of propranolol. Although HOP is considerably less lipophilic than propranolol, its volume of distribution, 6.4 +/- 0.8 liter/kg, surprisingly, was larger. Like propranolol, HOP appeared to be cleared entirely by metabolism. Whereas propranolol is metabolized mainly by oxidation, HOP was metabolized to sulfate (HOPS) and glucuronic acid (HOPG) conjugates. The plasma half-lives of these conjugates were 2 to 3 times longer than for HOP, reflecting a slow, continuous formation from HOP. This was established for HOPS by iv administration of synthetic HOPS. Morover, after HOP administration both formation and renal clearance of HOPS were stereoselective in favor of the R-enantiomer. In summary, the main conclusion of this study is that the large volume of distribution as well as high clearance through sulfation and glucuronidation may explain the low plasma HOP levels observed during propranolol therapy.  相似文献   
9.
10.
Introduction Failure to enter the coronary sinus (CS) with a guiding catheter and entering its tributaries remains challenging in left ventricle (LV) pacing lead implants for cardiac resynchronization therapy (CRT). A dual telescoping catheter system (8F outer/6F inner) is designed to provide the ability to adjust the catheter curve size, shape and/or reach to the patients’ anatomy avoiding the need for catheter change. Methods Five different designs for CS cannulation were randomly tested in 64 patients scheduled for CRT device implant. Results In 33 consecutive patients three adaptable telescoping guiding catheter systems were tested per patient, the adaptable catheters had higher overall cannulation success rates (68, 63 and 62%) compared to the fixed shape catheter (46%) and an greater cannulation success rate when the CS location was not known (70, 53 and 72% vs 33% for the fixed shape). In a second group of 31 CRT patients the two telescoping catheters had similar high levels of success (71–80%), with or without using the inner catheter. Conclusions The telescopic system is adaptable to a wide range of anatomical variations in patients and can result in a higher CS cannulation success rate due to its adjustability in the RA in search for the CS ostium. On top of this the inner catheter allows for sub-selecting the CS tributaries.  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