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   33180篇
  免费   2327篇
  国内免费   55篇
耳鼻咽喉   303篇
儿科学   1182篇
妇产科学   962篇
基础医学   4283篇
口腔科学   430篇
临床医学   4343篇
内科学   5957篇
皮肤病学   471篇
神经病学   3537篇
特种医学   596篇
外国民族医学   4篇
外科学   2972篇
综合类   328篇
一般理论   45篇
预防医学   4616篇
眼科学   507篇
药学   2209篇
中国医学   23篇
肿瘤学   2794篇
  2024年   44篇
  2023年   293篇
  2022年   518篇
  2021年   1120篇
  2020年   680篇
  2019年   1035篇
  2018年   1158篇
  2017年   834篇
  2016年   980篇
  2015年   1007篇
  2014年   1329篇
  2013年   1870篇
  2012年   2735篇
  2011年   2955篇
  2010年   1545篇
  2009年   1296篇
  2008年   2377篇
  2007年   2378篇
  2006年   2173篇
  2005年   2043篇
  2004年   1827篇
  2003年   1575篇
  2002年   1594篇
  2001年   205篇
  2000年   170篇
  1999年   200篇
  1998年   307篇
  1997年   238篇
  1996年   168篇
  1995年   178篇
  1994年   134篇
  1993年   119篇
  1992年   69篇
  1991年   47篇
  1990年   48篇
  1989年   39篇
  1988年   39篇
  1987年   35篇
  1986年   33篇
  1985年   16篇
  1984年   19篇
  1983年   29篇
  1982年   24篇
  1981年   18篇
  1980年   11篇
  1978年   4篇
  1977年   4篇
  1973年   4篇
  1972年   3篇
  1942年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Multiple options exist for the prevention of deep vein thrombosis (DVT) in medical inpatients. We sought to determine the cost-effectiveness of low-molecular-weight heparin (LMWH) relative to unfractionated heparin (UFH) for DVT prevention in this setting. We conducted a cost-effectiveness analysis from the perspective of a third-party payer employing a decision model and literature-based estimates for inputs. In the base-case analysis, LMWH had little impact on the rate of DVT. Despite higher acquisition costs, however, LMWHs resulted in net savings. Routine use of LMWH saves approximately US$89 per patient. The lower rate of heparin-induced thrombocytopenia (HIT) with LMWH accounted for this differential. Univariate sensitivity analysis revealed the model was moderately sensitive to the odds ratio of HIT with LMWH and the cost of HIT. Multivariate sensitivity analysis confirmed the LMWH approach dominated financially. 'Worst-case' scenario modeling, where LMWH actually increased the risk for DVT, had little effect on the rate of HIT, and was substantially more costly than UFH, still demonstrated that LMWHs were economically superior. Monte-Carlo simulation indicated the 95% confidence interval around the estimate for savings with LMWH ranged from US$7 to US$373. We conclude that, despite their higher cost, LMWHs for thromboprophylaxis in medical patients result in savings.  相似文献   
22.
Infections caused by extended-spectrum beta-lactamase (ESBL)-producing pathogens, particularly Klebsiella pneumoniae, are increasing. The epidemiology of ESBL-producing K. pneumoniae, the mechanisms of resistance, and treatment strategies for infections caused by these organisms are reviewed.  相似文献   
23.
24.
25.
26.
OBJECTIVES: To determine whether the increase in the incidence of injury found for the first summer season in which rugby league (RL) was played in the UK was repeated in subsequent summer seasons. DESIGN: A retrospective and prospective cohort study design. SETTING AND PARTICIPANTS: Injuries were recorded from all players who took part in 141 games over 3 summer seasons (1997 to 1999) for 1 professional team. These were compared against rates from previously collected data for 3 earlier winter and 1 summer season. ASSESSMENT OF RISK FACTORS: For each injury it was recorded in which season it occurred; how many games or training sessions, if any, were subsequently missed; the type, site and severity of injury. MAIN OUTCOME MEASURES: Injuries were reported as rate per 1000 hours, also broken down into severity according to the number of games missed and whether subsequent training sessions were missed. RESULTS: A sustained increase in injury incidence has been found comparing summer RL over RL played in the winter. There was an increase in injury rates for all sites and types, but not all reached significance. CONCLUSIONS: Data collected over 6 seasons indicate a higher risk of sustaining an injury playing summer RL, but the cause may be related to a combination of factors. These may include the ground or weather conditions associated with summer rugby, player characteristics or changes in the game itself and future research needs to investigate these further.  相似文献   
27.
28.
29.
Studies on the effectiveness of pain management have uniformly concluded that health care providers underestimate or undertreat pain. In the emergency department (ED) in which this study was conducted, physicians receive formal didactic and bedside teaching on pain recognition and management in order to heighten the awareness of patient's need for pain control. The purpose of this study was to determine if this outpatient pain management of patients with acute, painful conditions is better than that reported in the medical literature. In this prospective study, 110 adult patients who had an acute, painful diagnosis were telephoned 48 hours after discharge from the ED and asked if they felt their pain at home was well controlled. Patient satisfaction with pain control was higher (91%) than that reported in the medical literature. Also, pain medication was provided more frequently by this study's ED (95%). Education on pain awareness and treatment is a way to improve pain management.  相似文献   
30.
1. Left ventricular (LV) hypertrophy has been implicated in the reduction of baroreflex sensitivity present in hypertension. The aim of the current study was to investigate the mean arterial pressure-heart rate reflex (MAP-HR) in a model which induced left ventricular hypertrophy but no sustained blood pressure elevation. 2. Five mongrel dogs were exposed to transient blood pressure elevation of between 20 and 30 mmHg, through hindlimb compression using a pneumatic pressure suit, for 7 h per day, 6 days per week for 6 weeks. Resting blood pressure was not altered by the 6 week hindlimb compression intervention. 3. Echocardiographically determined LV mass (mean ± s.e.m.) was 116.0 ± 7.4 g prior to hindlimb compression (baseline) and elevated to 125.4 ± 8.1 g (P= 0.003) after 6 weeks of compression. A reduction in the early (E) to late (A) transmitral diastolic flow ratio (E/A) from 1.80 ± 0.06 at baseline to 1.54 ± 0.09 (P = 0.037) after the 6 week intervention suggested that cardiac compliance was reduced. 4. The maximum gain of the MAP-HR reflex, studied using the ‘steady-state’ drug technique, when blood pressure was normal, showed a trend for reduction from 3.85 ± 0.43 beats/min per mmHg at baseline to 3.10 ± 0.45 beats/min per mmHg (P= 0.067) after 6 weeks of compression. This gain reduction became significant after β-adrenoceptor blockade with propranolol (3.13 ± 0.55 vs 2.32 ± 0.25 beats/min per mmHg; P= 0.039). Covariant analysis showed a significant inverse correlation between LV mass and maximum gain (r= 0.96; P<0.001) during the 6 week compression period. 5. The MAP-HR reflex changes in this model mimic those present in hypertension and implicate cardiac hypertrophy as one possible mediator.  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