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   11438篇
  免费   714篇
  国内免费   37篇
耳鼻咽喉   85篇
儿科学   403篇
妇产科学   337篇
基础医学   1678篇
口腔科学   235篇
临床医学   1194篇
内科学   2042篇
皮肤病学   155篇
神经病学   1229篇
特种医学   423篇
外科学   1717篇
综合类   75篇
一般理论   4篇
预防医学   1050篇
眼科学   157篇
药学   643篇
中国医学   26篇
肿瘤学   736篇
  2023年   71篇
  2022年   141篇
  2021年   270篇
  2020年   169篇
  2019年   266篇
  2018年   279篇
  2017年   190篇
  2016年   233篇
  2015年   223篇
  2014年   339篇
  2013年   484篇
  2012年   677篇
  2011年   678篇
  2010年   347篇
  2009年   295篇
  2008年   524篇
  2007年   533篇
  2006年   533篇
  2005年   555篇
  2004年   502篇
  2003年   471篇
  2002年   404篇
  2001年   278篇
  2000年   284篇
  1999年   257篇
  1998年   113篇
  1997年   99篇
  1996年   80篇
  1995年   66篇
  1994年   68篇
  1993年   81篇
  1992年   194篇
  1991年   190篇
  1990年   164篇
  1989年   165篇
  1988年   138篇
  1987年   153篇
  1986年   128篇
  1985年   156篇
  1984年   112篇
  1983年   98篇
  1982年   60篇
  1981年   62篇
  1979年   69篇
  1978年   92篇
  1975年   58篇
  1974年   65篇
  1973年   63篇
  1972年   71篇
  1971年   62篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Introduction   QT interval prolongation may cause the potentially lethal tachyarrhythmia torsades de pointes ( 1 ). The cause of the QT interval prolongation may be a congenital mutation in genes encoding cardiac potassium and sodium channels ( 2 ) or be acquired following drug administration ( 3 ) or metabolic disorders ( 4 ). Among a few other drugs volatile anaesthetics prolong the QT interval. During the last few years sevoflurane has become the most used volatile anaesthetic for the induction of anaesthesia in infants.
Methods   This investigation, on infants aged from 1 to 6 months, was approved by the institutional ethic committee. Thirty-six otherwise healthy infants due to elective surgery were included in our study The patients were randomly assigned to one of two treatment groups. Group S ( n  = 24) was anaesthetised with sevoflurane, Group H was anaesthetised with halothane. ECG recordings were taken before the anaesthesia onset, 15 min after the first contact with the volatile anaesthetic and 60 min after the ending of the volatile gas exposition. QTc interval was calculated using the Bazett's formula ( 5 ).
Results   QTc interval was significantly ( P < 0.0002) (Table 1) lengthened 15 min after anaesthesia induction with sevoflurane as well as 60 min ( P < 0.01) after the ending of the gas exposition without any difference in age and gender. The QTc interval in patients anaesthetised with halothane did not show any significant change.  

  Table 1  相似文献   

2.
Mechanism of bronchodilator effect in chronic airflow limitation.   总被引:1,自引:0,他引:1       下载免费PDF全文
OBJECTIVE: To examine the mechanisms through which two bronchodilators (theophylline and salbutamol) influence dyspnea during daily activities. METHODS: Twenty-four patients with chronic airflow limitation participated in a multiple crossover, randomized, placebo-controlled trial. The effect of theophylline and salbutamol, alone or combined, on pulmonary function and dyspnea during daily activities was examined. Correlations of changes in forced expiratory volume in 1 second (FEV1) and maximum expiratory pressures (MIPs) (independent variables) and changes in dyspnea score during daily activities (dependent variable) were also examined. RESULTS: The two drugs proved to be beneficial the effects in general were additive rather than synergistic. The drugs improved the FEV1; theophylline significantly improved the MIPs. The correlation between the changes in FEV1 and those in dyspnea score, after adjustment for the changes in MIPs, was 0.55 (p less than 0.001). The correlation between the changes in MIPs and those in dyspnea score, after adjustment for the changes in FEV1, was 0.39 (p less than 0.001). CONCLUSIONS: Changes in airway calibre and in respiratory muscle strength play an independent and important role in dyspnea during daily activities in patients with chronic airflow limitation. Changes in airway calibre may be of greater importance.  相似文献   
3.
4.
5.
Lymphocytes from 10 paired colostrum and peripheral blood specimens were examined to determine if the colostral T cell population differs from the peripheral blood T cell population in subset distribution. The percentages of lymphocytes staining with OKT3, OKT4, and OKT8 murine monoclonal antibody were determined. Lymphocytes from colostrum were 74.7 +/- 2.5% OKT3+, 50.6 +/- 2.3% OKT4+, 24.0 +/- 1.7% OKT8+, whereas peripheral blood lymphocytes were 78.7 +/- 1.9% OKT3+, 48.4 +/- 1.4% OKT4+, and 29.8 +/- 1.6% OKT8+. The percentage of colostrum lymphocytes positive for OKT3 was significantly although not strikingly lower than the OKT3 percentage for blood lymphocytes (p less than 0.05). This difference was due to the lower percentage of OKT8 positive lymphocytes in colostrum compared with blood (p less than 0.01). Although the T cell subset distribution of colostrum generally appears to be similar to that in the peripheral blood, there were small differences in OKT3 and OKT8 percentages that were statistically significant suggesting the possibility of some selectivity of the colostral T cell population.  相似文献   
6.
PURPOSE: The use of gefitinib, the first drug approved to inhibit the epidermal growth factor receptor tyrosine kinase, is indicated in patients with non-small-cell lung cancer with tumors progressive after chemotherapy. The unique mechanism of action of this agent leads to distinctive patterns of response and toxicity in persons with lung cancer. Many of the principles of management relevant to gefitinib are distinct from those with conventional cytotoxic drugs. To meet this need, we present practical guidelines on the use of gefitinib in patients with non-small-cell lung cancer. METHODS: This article reviews gefitinib's indications, dosing, response phenomena, and patterns of relapse in individuals with radiographic response. RESULTS: We present our recommendations for the management of rash and diarrhea caused by this agent. CONCLUSION: This information can guide practitioners and help them inform their patients about what to expect when they receive gefitinib.  相似文献   
7.
8.
P Hildebrand  U J Roblick  R Keller  M Kleemann  L Mirow  H-P Bruch 《Der Chirurg》2007,78(6):494, 496-494, 500
Minimizing the access trauma of surgical interventions is becoming an essential task in modern surgery in order to make the treatment more comfortable for the patient. Minimally invasive surgery has had a major impact on the improvement of surgical results over the last decade. This is why such surgery is often named as the third patient friendly revolution in surgery after the introduction of asepsis and anesthesia. Operations that caused a huge strain on the patients in the past and led to immense costs for society because of the patient's lost working time and extensive rehabilitation, have lost their fear thanks to this technique. The physical strain is lower, the cosmetic effect is considerable and the costs for society might be reduced due to the significantly shorter duration of convalescence.Despite its known advantages, which have been reported in numerous studies, minimally invasive surgery has recently gained increased interest because of the installation of new accounting systems as well as strict budgeting and restricted resources.Realistic cost-benefit analysis and objectified quality controls are needed in order to guarantee innovative and patient friendly basic approaches in medicine in the future.  相似文献   
9.
10.
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