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   319篇
  免费   19篇
  国内免费   13篇
耳鼻咽喉   1篇
儿科学   30篇
妇产科学   1篇
基础医学   33篇
口腔科学   6篇
临床医学   31篇
内科学   90篇
皮肤病学   9篇
神经病学   6篇
特种医学   70篇
外科学   10篇
综合类   9篇
预防医学   28篇
药学   8篇
肿瘤学   19篇
  2021年   1篇
  2020年   3篇
  2019年   1篇
  2018年   6篇
  2017年   3篇
  2016年   3篇
  2015年   4篇
  2014年   6篇
  2013年   4篇
  2012年   1篇
  2011年   9篇
  2010年   12篇
  2009年   14篇
  2008年   14篇
  2007年   20篇
  2006年   8篇
  2005年   15篇
  2004年   12篇
  2003年   16篇
  2002年   7篇
  2001年   9篇
  2000年   5篇
  1999年   4篇
  1998年   15篇
  1997年   12篇
  1996年   12篇
  1995年   10篇
  1994年   17篇
  1993年   13篇
  1992年   3篇
  1991年   3篇
  1990年   5篇
  1989年   12篇
  1988年   9篇
  1987年   10篇
  1986年   6篇
  1985年   7篇
  1984年   5篇
  1983年   7篇
  1982年   4篇
  1981年   6篇
  1980年   4篇
  1979年   1篇
  1978年   6篇
  1977年   3篇
  1976年   4篇
排序方式: 共有351条查询结果,搜索用时 15 毫秒
71.
A Ziv  JR Boulet  GB Slap 《Pediatrics》1998,101(6):987-994
BACKGROUND: Adolescents in the United States have been shown to underutilize primary care services and therefore may rely heavily on emergency service. Although several small studies have explored local emergency services for youth, there are no published reports of adolescent utilization of emergency services on a national scale. Furthermore, emergency services data have not been aggregated according to the age subgroups used by the current guidelines for adolescent care. OBJECTIVE: To explore the utilization of emergency departments in the United States by early (11 to 14 years), middle (15 to 17 years), and late (18 to 21 years) adolescent subgroups. DESIGN: Secondary analysis of the emergency department component of the 1994 National Hospital Ambulatory Medical Care Survey. SETTING: Nationally representative sample of 418 emergency departments in the United States. PATIENTS: Approximately 26,547 visits by patients of all ages, representing 93.4 million total visits in 1994 and 14.8 million adolescent visits. OUTCOME MEASURES: Number of visits, health insurance, reasons for visits, urgency of visits, resulting diagnoses, and hospitalization rates. RESULTS: Adolescents accounted for 15.4% of the population and 15.8% of emergency department visits in 1994. Late adolescents were overrepresented in emergency department visits relative to their population proportion (6.8% of visits, 5.3% of population), whereas early adolescents were underrepresented (4.6% of visits, 5.9% of population). Lack of health insurance was more common among 11- to 21-year-olds (26.2%) than either children (13.6%) or adults (22.7%). By ages 18 to 21 years, 40.5% of male visits and 27.6% of female visits were uninsured. Injury-related visits were more common among adolescents (28.6%) than either children (23.1%) or adults (18.2%). Injury was the leading reason for visits among all adolescent age-sex subgroups (36.6% to 42.0% of male visits and 14.1% to 27.2% of female visits) except females aged 18 to 21 years for whom digestive reasons ranked first (18.8%). Injury was the leading diagnosis for all adolescent age-sex subgroups, with peaks at early adolescence of 61.6% for males and 45.8% for females. Across all adolescent age-sex subgroups, 3.1% to 5.3% of visits resulted in hospitalization, and 41.0% to 52.5% of visits were urgent. These rates did not differ from those of children but were lower than those of adults. CONCLUSIONS: Utilization of emergency departments increases and health insurance decreases during adolescence, suggesting that adolescents with inadequate health insurance may rely heavily on emergency departments for their health care needs. Most adolescent visits to emergency departments are not urgent and might be better treated through nonemergency, primary care sites.  相似文献   
72.
We examined the properties and ultraviolet exposure parameters of tar smarts in an effort to elucidate the mechanisms involved. We showed that irradiation with 1 minimal smarting dose (MSD) of UVA immediately following tar removal lowered the MSD for 6 h, demonstrated by subsequent challenge with UVA. Following 3 MSDs this "memory" effect was demonstrable for 24 h. The smarting reaction was area dependent--smaller areas of exposure require higher doses of UVA to induce smarting. Smarting followed reciprocity over a 6-fold range of irradiances (2-12.5 mW/cm2) but higher irradiances required higher doses of UVA, perhaps due to a delay in the recognition and reporting of smarting. The smarting reaction and delayed erythema due to UVA and tar were equally blocked by sunscreen.  相似文献   
73.
Unilateral lung agenesis is a rare congenital condition of unknown etiology. A 33-year-old nullipara with right lung agenesis and scoliosis was admitted to the hospital at 30 weeks of gestation because of oligohydramnios. At 32 weeks she was treated for an upper respiratory tract infection with azithromycin. She went into premature labor at 34 weeks and was delivered by Cesarean for breech presentation. Both mother and infant did well.  相似文献   
74.
75.
76.
77.
78.
BACKGROUND: High-resolution CT (HRCT) of the lungs has become an essential component to evaluate patients with diffuse lung disease. Little is known, however, about the current practices of pulmonologists caring for patients with these complex conditions, and, in particular, whether HRCT can obviate the need for surgical lung biopsy. OBJECTIVES: To investigate the practices of pulmonologists concerning the acceptability of a HRCT diagnosis in lieu of lung biopsy in diffuse lung disease. METHODS: We asked practicing pulmonologists among membership of the American College of Chest Physicians whether HRCT results could replace lung biopsy in 16 diffuse lung diseases. Responses were examined in light of published evidence, practice guidelines, and certain practice parameters. RESULTS: Two hundred and thirty (52.6%) of 437 eligible physicians responded. Sixty-seven percent (67%) of respondents accepted HRCT diagnosis for idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP) despite their awareness of guidelines recommending histological diagnosis. Most would not accept a radiologic diagnosis for lymphangioleiomyomatosis (LAM; 37%) or eosinophilic granuloma (Langerhans' cell histiocytosis, LCH; 19%), even though CT findings are frequently characteristic. Responses were similar by type of clinical practice and recency of fellowship training. Chest physicians who referred patients for HRCT more frequently were more likely to accept HRCT diagnosis (p=0.008) and those who had higher self-ratings of proficiency in reading HRCT (p = 0.004) were more likely to believe HRCT often suggests specific diagnosis. CONCLUSIONS: Most US pulmonologists will accept an HRCT diagnosis of IPF/UIP without lung biopsy, but are reluctant to do so for most other diffuse lung conditions including LAM and LCH.  相似文献   
79.
BACKGROUND: Overuse of inhaled beta-agonists and underuse of inhaled corticosteroids by patients with asthma may have adverse consequences. This study was performed to identify factors associated with misuse of these types of asthma medication. METHODS: We examined baseline data from a longitudinal survey of adult patients with asthma. The setting was a consortium of 15 national managed care organizations serving 11 large employers. Baseline surveys were completed by 6612 health plan enrollees at least 18 years old who had had at least 2 visits with a diagnostic code for asthma in the preceding 2 years. The main outcome measures were the overuse of inhaled beta-agonists and the underuse of inhaled corticosteroids. Independent variables were patient and process of care factors. RESULTS: Among patients with moderate or severe asthma, 16% of users of inhaled beta-agonists reported overuse (>8 puffs per day on days of use), and 64% of users of inhaled corticosteroids reported underuse (use on < or =4 days/wk or < or =4 puffs per day). Overuse of inhaled beta-agonists was most strongly associated with concomitant treatment with inhaled corticosteroids or anticholinergic agents, increased asthma symptom severity, problems in obtaining asthma medication, and male sex. Underuse of inhaled corticosteroids was associated with nonwhite race, younger age (18 to 34 years), lower use of inhaled beta-agonist, lower symptom severity, and not possessing a peak flow meter. Rates of misuse of medication also varied by speciality of the patient's provider (generalist, allergist, or pulmonologist). CONCLUSIONS: Overuse of inhaled beta-agonists may be caused by symptom severity, while underusers of corticosteroids may interrupt use as symptoms abate. This study demonstrated an important opportunity to improve medication use among patients with asthma.  相似文献   
80.
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