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   1767篇
  免费   195篇
  国内免费   9篇
耳鼻咽喉   16篇
儿科学   30篇
妇产科学   28篇
基础医学   301篇
口腔科学   28篇
临床医学   202篇
内科学   374篇
皮肤病学   35篇
神经病学   99篇
特种医学   21篇
外科学   251篇
综合类   51篇
一般理论   1篇
预防医学   259篇
眼科学   19篇
药学   119篇
中国医学   4篇
肿瘤学   133篇
  2023年   21篇
  2022年   16篇
  2021年   73篇
  2020年   46篇
  2019年   52篇
  2018年   73篇
  2017年   50篇
  2016年   48篇
  2015年   56篇
  2014年   76篇
  2013年   84篇
  2012年   130篇
  2011年   139篇
  2010年   61篇
  2009年   55篇
  2008年   95篇
  2007年   114篇
  2006年   93篇
  2005年   78篇
  2004年   78篇
  2003年   50篇
  2002年   56篇
  2001年   29篇
  2000年   37篇
  1999年   30篇
  1998年   27篇
  1997年   21篇
  1996年   18篇
  1995年   14篇
  1994年   19篇
  1993年   9篇
  1992年   25篇
  1991年   18篇
  1990年   12篇
  1989年   17篇
  1988年   22篇
  1987年   22篇
  1986年   12篇
  1985年   14篇
  1984年   8篇
  1983年   6篇
  1982年   5篇
  1981年   5篇
  1980年   4篇
  1977年   7篇
  1976年   4篇
  1974年   9篇
  1972年   6篇
  1961年   3篇
  1955年   3篇
排序方式: 共有1971条查询结果,搜索用时 265 毫秒
1.
2.

Background  

A public hospital in New Mexico required collection of 50% of estimated costs prior to elective surgeries for self-pay patients. This study assesses the impact of this policy on access to elective surgical procedures.  相似文献   
3.
This paper reports the proceedings of the discussion panel assigned to look at clinical aspects of quality in emergency medicine. One of the seven stated objectives of the Academic Emergency Medicine consensus conference on quality in emergency medicine was to educate emergency physicians regarding quality measures and quality improvement as essential aspects of the practice of emergency medicine. Another topic of interest was a discussion of the value of information technology in facilitating quality care in the clinical practice of emergency medicine. It is important to note that this is not intended to be a comprehensive review of this extensive topic, but instead is designed to report the discussion that occurred at this session of the consensus conference.  相似文献   
4.
5.
Since the Bhopal disaster, in which the causal agent was methyl isocyanate (MIC), exposed people have complained of various disorders including neuromuscular dysfunction. In an attempt to gain some information about the response of muscle tissue to MIC its effects were investigated in cells in culture isolated from muscle of 2 day old rats. After treatment with a range of MIC concentrations (0.025-0.5 microliter/5 ml culture) the total number of nuclei of the two main cell types (fibroblasts and myoblasts) and the number of nuclei in muscle fibres (myotubes) were recorded. At lower doses which had little effect on the total number of nuclei, the formation of muscle fibres--that is, fusion of muscle cells--was prevented as the proportion of nuclei in myotubes was decreased. At higher doses both cell types were killed. This would suggest either an effect on muscle differentiation or a selective toxicity towards myoblasts. The observations were supported by light and electron microscopy.  相似文献   
6.
BACKGROUND: Intrahepatic stones, though common in East Asia, are uncommon in India. There is paucity of data from India regarding the treatment and long-term outcome of patients with intrahepatic stones. METHODS: We retrospectively analyzed medical records of 35 patients with intrahepatic stones who had been treated surgically. Endoscopic biliary drainage had been used in patients who presented with acute cholangitis. Intraoperative stone clearance was confirmed by choledochoscopy and intraoperative cholangiography. Outcome of surgery, frequency and subsequent management of recurrent intrahepatic stones, and factors associated with stone recurrence and cholangitis were analyzed. RESULTS: Twenty-one (60%) patients had bilobar disease. Eight patients underwent hepatectomy and 16 hepatico-jejunostomy with access loop; 12 of these were jejuno-duodenal anastomoses. Postoperative morbidity was observed in 10 patients (29%). Recurrence of stones occurred in 12 patients (34%) and cholangitis in 9 patients (26%). Presence of bilobar disease and associated biliary strictures were associated with recurrent cholangitis (p< 0.05). Two patients (6%) required re-operation for recurrent cholangitis. Complete removal of recurrent stones using conventional endoscope was possible through jejuno-duodenostomy in all 5 cases who had this type of access loop construction. CONCLUSION: Surgical treatment for intrahepatic stones depends on the site of involvement. Construction of a jejuno-duodenal access loop in patients with bilobar disease and intrahepatic strictures is helpful in facilitating postoperative stone clearance. A multidisciplinary approach is beneficial especially when the disease is bilobar and recurrent in type.  相似文献   
7.
8.
Summary There are many issues in firefighting that involve human factors and cardiopulmonary conditioning. Population-based mortality and disability surveillance studies suggest a relatively small but significant excess of disability but not mortality from nonmalignant cardiovascular disease for fire fighters. More targeted cohort and case-control studies do not support such an excess and instead suggest a strong healthy worker effect. Pulmonary function among fire fighters has been extensively studied, with contradictory findings. Extreme exposures and long-term exposure in combination with cigarette smoking may be risk factors for respiratory disorders and accelerated decline in airflow. It appears likely that individual fire fighters who show early signs of illness are often selectively transferred out of active firefighting positions. Despite exposure to substances such as carbon monoxide that may predispose to cardiovascular mortality and morbidity, excesses are not consistently shown in mortality studies. Clinical studies of individual fire fighters do suggest an elevated risk for myocardial ischemia. The ergonomic demands of firefighting are extreme at peak activity because of high energy costs for activities such as climbing aerial ladders, the positive heat balance from endogenous and absorbed environmental heat, and encumbrance by bulky but necessary protective equipment. The psychological stresses of firefighting include long periods of relative inactivity punctuated by highly stressful alarms and extremely stressful situations such as rescues, as reflected in physiological and biochemical indicators. Fire fighters are at risk for depression and posttraumatic stress disorder, although morale overall is generally much higher than in comparable occupations. Women firefighter candidates as a group perform less well on selection test simulating the demands of active firefighting, but some individual women perform very well.  相似文献   
9.
The toxicity of paracetamol has been investigated in freshly isolated hamster hepatocytes. Two phases of toxicity have been identified. In phase 1, metabolic activation of paracetamol occurs with depletion of glutathione. In phase 2, there is progressive morphological damage, leading ultimately to cell death. This occurs even in the absence of further exposure to paracetamol. The thiol reductant, dithiothreitol, added at the start of phase 2, prevents and reverses the toxicological damage that would otherwise occur. Thus, it is most likely that paracetamol causes hepatotoxicity through oxidation of SH groups in key enzymes. N-Acetylcysteine, but not methionine, has an effect similar to that of dithiothreitol. This difference is probably due to oxidation of the enzymes involved in the conversion of methionine to cysteine, whereas N-acetylcysteine can still serve as a precursor of glutathione. The glutathione can act both by adduct formation with the metabolite of paracetamol and as a thiol reductant. Species differences in sensitivity to paracetamol toxicity were shown to be due to differences in the rate of oxidation of the drug to its toxic metabolite. Most people are relatively poor activators of paracetamol, but in few subjects the reaction proceeds quite rapidly, rendering such individuals more sensitive to the hepatotoxic effects of the drug.  相似文献   
10.
Adequate ventilation is required for successful cardiopulmonary resuscitation (CPR). Operator characteristics that influence ventilation performance are not well defined. This study compared ventilation performance and operator characteristics in 74 medical personnel using a self-inflating anesthesia bag. Ventilation device, operator hand size, ventilation technique, average tidal volume, cumulative minute ventilation, and ventilation pressures were recorded during 3 minutes of ventilation. Ventilation volumes and airway pressures were not correlated with hand size or device type. Techniques that used one hand to squeeze the bag resulted in significantly lower average tidal volume than two-handed techniques, with no significant difference in peak or average airway pressure. There was no difference between emergency department and prehospital personnel in average tidal volume delivered. However, prehospital personnel ventilated at significantly higher airway pressures. Emergency department nurses delivered the greatest average tidal volume (923 cc), while emergency department physicians delivered the least (775 cc). Paramedics recorded the highest airway pressures (average, 53 cm H2O; peak, 72 cm H2O), while respiratory therapists recorded the lowest pressures (average, 34 cm H2O; peak, 54 cm H2O). Ventilation during CPR is a complex, learned skill. Large variation exists among different operators. However, appropriate tidal volumes can be delivered using safe airway pressures. Ongoing assessment and retraining of individuals performing ventilation during CPR are essential.  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