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   998篇
  免费   91篇
  国内免费   22篇
耳鼻咽喉   4篇
儿科学   51篇
妇产科学   14篇
基础医学   157篇
口腔科学   45篇
临床医学   103篇
内科学   161篇
皮肤病学   33篇
神经病学   54篇
特种医学   225篇
外科学   74篇
综合类   34篇
预防医学   45篇
眼科学   10篇
药学   52篇
肿瘤学   49篇
  2022年   6篇
  2021年   13篇
  2020年   6篇
  2019年   9篇
  2018年   10篇
  2017年   11篇
  2016年   12篇
  2015年   14篇
  2014年   14篇
  2013年   17篇
  2012年   12篇
  2011年   25篇
  2010年   27篇
  2009年   30篇
  2008年   33篇
  2007年   29篇
  2006年   25篇
  2005年   15篇
  2004年   22篇
  2003年   17篇
  2002年   18篇
  2001年   20篇
  2000年   20篇
  1999年   19篇
  1998年   45篇
  1997年   48篇
  1996年   42篇
  1995年   38篇
  1994年   25篇
  1993年   34篇
  1992年   25篇
  1991年   23篇
  1990年   17篇
  1989年   28篇
  1988年   43篇
  1987年   56篇
  1986年   32篇
  1985年   22篇
  1984年   9篇
  1983年   15篇
  1982年   15篇
  1981年   23篇
  1980年   19篇
  1979年   10篇
  1978年   10篇
  1977年   10篇
  1976年   22篇
  1975年   11篇
  1927年   4篇
  1926年   6篇
排序方式: 共有1111条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
OBJECTIVE: To evaluate the effectiveness of continuous positive airway pressure (CPAP) therapy in the treatment of hypernasality following traumatic brain injury (TBI). DESIGN: An A-B-A experimental research design. Assessments were conducted prior to commencement of the program, midway, immediately posttreatment, and 1 month after completion of the CPAP therapy program. PARTICIPANTS: Three adults with dysarthria and moderate to severe hypernasality subsequent to TBI. OUTCOME MEASURES: Perceptual evaluation using the Frenchay Dysarthria Assessment, the Assessment of Intelligibility of Dysarthric Speech, and a speech sample analysis, and instrumental evaluation using the Nasometer. RESULTS: Between assessment periods, varying degrees of improvement in hypernasality and sentence intelligibility were noted. At the 1-month post-CPAP assessment, all 3 participants demonstrated reduced nasalance values, and 2 exhibited increased sentence intelligibility. CONCLUSIONS: CPAP may be a valuable treatment of impaired velopharyngeal function in the TBI population.  相似文献   
56.
57.
Reviews of stored electrograms from ICDs revealed a 5-30% incidence of short-long-short intervals preceding the onset of recurrent ventricular tachyarrhythmias. Rate stabilization by dedicated antibradycardia pacing algorithms has, therefore, been suggested to prevent onset of pause dependent tachyarrhythmias. However, the clinical efficacy of this approach has not been studied systematically. In a prospective multicenter crossover study, patients were randomized to activation or deactivation of an implemented ventricular rate stabilization algorithm (VRS) after first implant of a dual chamber ICD. After 3 months, all patients were crossed over to the alternate programming. The rate of appropriate spontaneous VA episodes was compared between VRS On and VRS Off. Stored electrograms were reviewed for evaluation of the mode of onset of tachyarrhythmias. Overall efficacy analysis was based on 309 patients enrolled in the study. Forty percent (124/309) of the patients experienced 4,973 VA episodes. Based on an intention-to-treat analysis, VRS Off and On arrhythmia incidence was 10.2 and 6.6 normalized to 3 months, respectively (risk reduction 35%; P = 0.18) On an on-treatment basis, a reduction from 9.0 episodes to 8.1 episodes (10% risk reduction, P = 0.24) was seen. In an extended Cox model adjusting for confounding variables, the relative risk for recurrent episodes was 0.92 during VRS On compared to Off (95% CI: 0.58-1.48; P = 0.74). During VRS Off, pause dependent onset was documented in only 36 (8%) of 427 visually analyzed episodes. There was no significant reduction in the incidence of recurrent ventricular tachyarrhythmias with VRS On compared to the Off programming in this prospective study.  相似文献   
58.
BACKGROUND: Rates of patient adherence (compliance) to pharmacotherapy range from <5% to >90%. Negative determinants include multiple daily dosing (MDD), chronic duration, and asymptomatic disease. Reports suggest that once-daily (QD) dosing may improve adherence, but their findings are inconclusive. Objective: The purpose of this study was to compare the rates of adherence with QD, twice-daily (BID), and MDD antihypertensive drug regimens. METHODS: MEDLINE, Embase, and International Pharmaceutical Abstracts databases were searched to identify comparative trials of patient adherence to antihypertensive medication in solid, oral formulations. Data were combined using a random-effects meta-analytic model. RESULTS: Eight studies involving a total of 11,485 observations were included (1,830 for QD dosing, 4405 for BID dosing, 4147 for dosing >2 times daily [>BID], and 9655 for MDD), in which the primary objective was to assess adherence. The average adherence rate for QD dosing (91.4%, SD = 2.2%) was significantly higher (Z = 4.46, P < 0.001) than for MDD (83.2%, SD = 3.5%). This rate was also significantly higher (Z = 2.22, P = 0.026) than for BID dosing (92.7% [SD = 2.3%] vs 87.1% [SD = 2.9%]). The difference in adherence rates between BID dosing (90.8%, SD = 4.7%) and >BID dosing (86.3%, SD = 6.7%) was not significant (Z = 1.82, P = 0.069). CONCLUSIONS: The results of this meta-analysis demonstrate that with antihypertensive medications, QD dosing regimens are associated with higher rates of adherence than either BID or MDD regimens.  相似文献   
59.
Innovative research relating oceans and human health is advancing our understanding of disease-causing organisms in coastal ecosystems. Novel techniques are elucidating the loading, transport and fate of pathogens in coastal ecosystems, and identifying sources of contamination. This research is facilitating improved risk assessments for seafood consumers and those who use the oceans for recreation. A number of challenges still remain and define future directions of research and public policy. Sample processing and molecular detection techniques need to be advanced to allow rapid and specific identification of microbes of public health concern from complex environmental samples. Water quality standards need to be updated to more accurately reflect health risks and to provide managers with improved tools for decision-making. Greater discrimination of virulent versus harmless microbes is needed to identify environmental reservoirs of pathogens and factors leading to human infections. Investigations must include examination of microbial community dynamics that may be important from a human health perspective. Further research is needed to evaluate the ecology of non-enteric water-transmitted diseases. Sentinels should also be established and monitored, providing early warning of dangers to ecosystem health. Taken together, this effort will provide more reliable information about public health risks associated with beaches and seafood consumption, and how human activities can affect their exposure to disease-causing organisms from the oceans.  相似文献   
60.
BACKGROUND: By 2016, the proportion of Canadians older than 65 years of age will increase to 16%, and there will be an increase in the absolute number of cases of cardiovascular disease in older Canadians. The Canadian Heart Health Surveys database provides information about this population upon which health policy related to cardiovascular disease can be based. This paper presents for the first time population-based data on the risk factors for cardiovascular disease in older Canadians. METHODS: Canadians from all 10 provinces participated in surveys of cardiovascular risk factors; health insurance registries were used as sampling frames. In each province, probability samples of 2200 adults 18 to 74 years old not living in institutions, on reserves or in military camps were asked to participate in interviews and to undergo testing at clinics for major risk factors for cardiovascular disease. RESULTS: A total of 2739 men (response rate 70%) and 2617 women (response rate 66%) aged 55 to 74 years participated in the survey and also provided follow-up clinical measurements at the clinic. Overall, 52% of participants were hypertensive, 26% had isolated systolic hypertension, and 30% had a total blood cholesterol level of 6.2 mmol/L or greater. Rates of current smoking were lower in women than men (17% v. 22%). Overall, 87% of men and 78% of women who were current smokers smoked at least 10 cigarettes per day. Only slightly more than half of participants exercised at least once a week for at least 15 minutes, and almost half had a body mass index of 27 or greater. In only 4% was no major risk factor for cardiovascular disease detected. INTERPRETATION: Significant numbers of older Canadians have one or more major risk factors for cardiovascular disease. Many of these risk factors are amenable to modification.  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